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VII.- THE FACIAL NERVE ANATOMY: (A) The Nuclear and Intranuclear Pathway (L.M.N.): The motor nucleus of the facial nerve is located in the ventral part of the tegmentum of the pons near the midline. Fibres originating from this nucleus pass backwards in the pons forming a loop around the sixth nerve nucleus, then emerge from the lateral surface of the pons. The facial nerve, nervus intermedius and 8th nerve pass together from the pons to the internal acoustic meatus. The facial nerve passes through the facial canal in the petrous portion of the temporal bone. It emerges to the face through the stylomastoid for amen. At the angle of the facial canal, the nerve expands to form the geniculate ganglion which gives the nervus intermedius that ends in the nucleus of the tractus solitarius and the greater and lesser superficial petrosal nerves. During its course within the facial canal, the facial nerve gives the nerve to stapedius muscle and the chorda tympani. The latter emerges from the skull through the anterior canaliculus for the chorda tympani to join the lingual nerve which is a branch of the mandibular division of the fifth nerve. After emerging from the stylomastoid foramen the facial nerve gives branches to: the stylohyoid muscle, the posterior belly of the digastric and the occipital belly of the occipitofrontalis. It then divides within the parotid gland into 2 main branches; 1. Temporofacial: supplying the frontalis, orbicularis oculi and zygomatic muscles. 2. Cervicofacial: to the orbicularis oris, buccinator and platysma. Cerebral cortex The corticobulbar projections to the motor nucleus of the facial nerve. The shaded areas in the nuclei control muscles of the lower twothirds of the face. The nonshaded areas control the muscles of the upper one-third of the face. The muscles of the lower two-thirds are under only contralateral control of the cerebral cortex, whereas the muscles of the upper onethird are under bilateral control of the cerebral cortex. Motor Nucleus of the Facial NerVe 54 Cortico-bulbar fibres (U.M.N.) to the facial nucleus (B) The Supranuclear Pathway (U.M.N.): 1 . Corticospinal fibres : for voluntary facial movements, originate in the lower part of the motor cortex, descend in the corona radiata, genu of the internal capsule, cerebral peduncle, to the pons, where they decussate to supply the whole facial nucleus of the opposite side. The superior part of each facial nucleus (innervating the upper half of the face) receives additional supranuclear fibres from the ipsilateral pyramidal tract. 2 . Mimic fibres : for emotional and associative movements of the face, arise from the extrapyramidal system and reach the facial nuclei in the pons. Functions of the Facial Nerve : 1. Motor to the following muscles: (i) Occipitofrontalis. (ii) Orbicularis oculi. (iii) Orbicularis oris. (iv) Buccinator. (v) Stylohyoid. (vi) Stapedius. (vii) Platysma. (viii) Posterior belly of the digastric. 2 . Secretory to the submaxillary and sublingual salivary glands (by the chorda tympani) and to the lacrimal glands (by the superficial petrosal nerve). 3 . Sensations of the external auditory meatus and pre- auricular area. 4 . Proprioceptive sensations from the facial muscles. 5 . Taste sensation from the anterior 2 thirds of the tongue (by the chorda tympani). Facial Paralysis may be due to : 1 . A supranuclear lesion affecting the pyramidal fibres. 2 . A supranuclear lesion affecting the mimic fibres concerned in emotional movements of the face. 3 . Lower motor neurone lesions (Nuclear and infranuclear). 4 . Disorders of the facial muscles. Causes of Bilateral Facial Pals> (Facial Diplegia): 1. Congenital absence of facial nuclei. 2 . Polyneuritis : e.g. alcoholic, diphtheritic, leprotic, diabetic and acute infective polyneuritis. 3 . Pontine lesions e.g. basilar artery thrombosis, brain - stem encephalitis,pontine tumour,...etc. 4 . Bilateral otitis media. 5 . Syphilitic basal meningitis and carcinomatous meningitis. 6 . Uveoparotid syndrome of sarcoidosis. 7 . Double Bell's palsy. BELL'S PALSY Definition : A lower motor neurone facial palsy of acute onset due to non-suppurative inflammation of the seventh nerve within the stylomastoid foramen. Aetiology: (i) Age : any age from infancy to old age, commonest in young adults. (ii) Sex: Males are affected more than females. (iii) Exposure to cold or air draft. (iv) May follow acute infection of the nasopharynx. (v) Few cases are due to the virus of herpes zoster. (vi) Rheumatic interstitial neuritis of the facial nerve. (vii) Perineuritis or periostitis with oedema compressing the nerve. (viii) Ischaemic paralysis secondary to oedema. Clinical picture: * Usually unilateral, very rarely bilateral. 55 * Onset is sudden, with pain within the ear, in the mastoid region, or around the angle of the jaw. * Paralysis affects both upper and lower facial muscles where voluntary, emotional and associated movements are paralysed. * Drooping of the eyebrow with inability to raise it. * Obliteration of the wrinkles of the forehead. * Wider palpebral fissure on the affected side. * Inability to close the eye with upward rolling of the eyeball on trying to do so (Negro's sign or Bell's phenomenon). * Eversion of the lower lid with tearing. * Obliteration of the nasolabial furrow. * Deviation of the angle of the mouth to the sound side. * Inability to retract the angle of the mouth and to whistle. * The cheek puffs out in respiration and on blowing. * Accumulation of food between the teeth and the cheek. * Involvement of the chorda tympani may occur and produces loss of taste on the anterior 2 thirds of the tongue. * Involvement of the nerve to stapedius may occur resulting in hyperacusis * Reaction of degeneration may occur. * EMG of the facial muscles & facial nerve conduction studies help in diagnosis & follow up. Differential Diagnosis: Bell's palsy should be distinguished from : 1. Facial palsy due to pontine lesions :5,6,7th nerve palsies + long tracts. 2 . Lesions in the posterior fossa: 8th nerve is usually involved. 3 . Facial palsy secondary to otitis media: Evidence of otitis media with ear discharge. 4 . Multiple sclerosis (M.S.) 5 . Syphilis. 6 . Facioplegic migraine: recurrent facial palsy + migrainous headache. Prognosis: 1. Complete recovery occurs in a good percentage of cases within few weeks. 2 . Contracture may develop in the paralysed muscles. 3 . Clonic facial spasm may occur due to partial recovery. 4 . The crocodile tears syndrome: Unilateral lacrimation on eating due to regenerating facial nerve fibres to the lacrimal gland. 5 . Recurrent facial palsy is rare. Treatment: (A) Medical: 1. Hot fomentation, short wave therapy and massage. 2 . Galvanic stimulation of the paralysed muscles. 3 . Corticosteroids, or A.C.T.H. are helpful if given early. 4 . Other drugs e.g. salicylates, Bl, B12 and B complex. 5 . Adhesive strapping above and below the mouth on the paralysed side to prevent deviation of the mouth to the sound side. (B) Surgical: 1. Decompression of the facial canal and incision of the nerve sheath. 2 . AutografL 3 . Plastic surgery to correct facial asymmetry. 56 Differential Diagnosis Between Upper and Lower Motor Neurone Facial Palsy Panriysfe of 0w Face Bilateral Facial Paralysis—Bell's Phenomenon Facial nerve nucleus Petrous bone Fifth nerve gangli Maxillary division Lacrimal gland The facial nerve. Geniculate gangl of facial nerve Lingual Branches to facial muscles nerve and platysma Cervical branch of facial nerve -THE AUDITORY (VESTIBULOCOCHLEAR) NERVE Anatomy : It consists of 2 divisions: (A) The cochlear (concerned in hearing), & (B ) The vestibular nerve (concerned in equilibrium and postural functions) (A) THE COCHLEAR NERVE : Its fibres originate from the cochlea, pass in the 8th nerve within the internal acoustic meatus across the posterior fossa crossing the cerebellopontine angle lateral to the facial nerve, from which it is separated by the nervus intermedius. They enter t he lateral aspect of the lower border of the pons to end in the cochlear nucleus, which gives fibres that cross to the opposite side by 2 alternative pathways; (/) Fibres from the dorsal part of the nucleus cross beneath the floor of the fourth ventricle forming the striae acousticae. (ii) Fibres from the ventral part of the nucleus enter the olive of the ipsilateral side, which gives new fibres that cross in the ventral part of the pons as ti\Q fibres of the trapezium. Both dorsal and ventral fibres ascend in the lateral lemniscus to the inferior colliculus and the medial geniculate body, from which new fibres pass to the cortical auditory centre in the posterior part of the superior temporal gyrus. Lesions of the Cochlear Nerve result in : 1. Tinnitus. 2 . Deafness. (B) THE VESTIBULAR NERVE : Its fibres arise from the Labyrinth (semicircular canals, utricle and saccule). It joins the cochlear nerve in the internal meatus crossing the cerebellopontine angle to ente r the pons. Its fibres end in a number of nuclei in the brain-stem. Some fibres go to the eye muscles, others run to the cerebellum, thalamus and to the cortical centres in the posterior parts of the temporal lobes. Lesions of the Vestibular Nerve result in : 1. Vertigo. 2 . Spontaneous Nystagmus. 3 . Ipsilateral incoordination of limbs. Causes of Tinnitus: 1 2 4 5 . Wax in the external acoustic meatus . . Catarrh of the Eustachian tube. 3 . Acute otitis media. . Forcible contraction of the orbicularis oculi. . Drugs e.g. quinine, salicylates, amyl nitrite and streptomycin (tinnitus precedes the deafness caused by the latter drug). 6 . Acute labyrinthitis. 7 . Arteriosclerosis. 8 . Anaemia. 9 . Aortic incontinence. 10 . Otosclerosis 11 . Carotid - cavernous sinus aneurysm, congenital I.C. aneurysm, arterial angioma may be heard by the patient as rhythmical bruit. 12 . Acoustic neuroma. 13 . Syphilitic meningitis involving the 8th nerve. 14 . Vascular lesions of the pons may cause tinnitus and deafness. 15 . Irritative lesions of the auditory cortex e.g. temporal lobe tumours produce auditory hallucinations. 16 . Endogenous depression. Treatment of Tinnitus: (i) Treat the cause. (ii) Sedatives e.g. phenobarbitone. (MI ) Antidepressants. (iv) Destruction of the cochlea or division of the 8th nerve in severe cases with intolerable tinnitus. Causes of Nerve Deafness : 1 . Lesions of the internal ear e.g. trauma, chronic otitis interna, acute labyrinthitis, meningococcal meningitis, mumps, congenital syphilis, cogenital deaf mutism, Otosclerosis and atheroma. 2 . Toxic e.g. streptomycin, neomycin, aspirin, quinine, tobacco, & alcohol. 3 . Traumatic e.g. fractures of the skull involving the petrous temporal bone, & chronic exposure to loud noise. 57 4 . Acoustic neuroma. 5 . Intratemporal epidermoid. 6 . Paget's disease (osteitis deformans). 7 . Meningovascular syphilis. 8 . Other causes: e.g. polyneuritis cranialis and avitaminosis. 9 . Vascular lesions of the pons. 10 . Multiple sclerosis (M.S.) 11. Tumours of the midbrain or pineal body. 12 . Bilateral temporal lobe lesions. 13 . Birth injury, anoxia and kernicterus. VERTIGO Definition : It is the consciousness of disordered orientation of the body in space, i.e. a sense of rotation of the patient or of his surroundings. Causes of Vertigo: 1. Psychogenic Vertigo (Giddiness) e.g. in hysteria and anxiety neurosis. 2 . Vertigo due to Cortical Disturbance: e.g. aura of a temporal lobe epilepsy, basilar artery migraine and intracranial tumour. 3 . Ocular Vertigo : e.g. giddiness at heights and in patients with squint(external ophthalmoplegia). 4 . Cerebellar Vertigo : e.g. in lesions of the flocculonodular lobe, intracerebellar haemorrhage and at the onset of posterior inferior cerebellar artery thrombosis. 5 . Brain-stem lesions e.g. vascular or neoplastic lesions, M.S., syringobulbia, streptomycin therapy and transient brain-stem ischaemia evoked by head movement in patients with vertebral artery atheroma and cervical spondylosis (Vertebro-basilar insufficiency). 6 . Vestibular Neuronitis may cause paroxysmal vertigo not associated with tinnitus or deafness. 7 . Epidemic Vertigo: may be due to a mild brain-stem encephalitis. 8 . Auditory nerve lesions e.g. acoustic neuroma and basal meningitis. 9 . Aural Vertigo : e.g. (i) Wax in the external meatus. (ii) Blockage of the Eustachian tube. (iii) Otitis media (acute and chronic). (iv) Otosclerosis. (v) Ischaemia due to atheroma, anaemia and incraesed IC T. (vi) Herpes zoster of the geniculate ganglion. (vii) Acute virus labyrinthitis. (viii) Motion Sickness. (ix) Meniere's syndrome. (x) Drugs e.g. quinine and salicylates. (xi) Head injury. (xii) Benign positional vertigo. MENIERE'S SYNDROME Aetiology: is unknown. * Age: middle age * Sex: males more than females(3:2) * Septic foci in the teeth ; tonsils or nasal sinuses . * Association with migraine. * Allergy. Clinically: 1. Progressive deafness and tinnitus . 2. Recurrent attacks of vertigo 3 . Nausea, vomiting , prostraion and diplopia. 4 . Unsteadiness and staggering 5 . Rotary nystagmus . Treatment: (A) Medical (i) Rest during the attack . (ii) Chlorpromazine , 50 mg.i.m. (iii) Phenobarbitone. (iv) Antihistaminics. (v) Vasodilators. (vi) Eradication of any septic foci, (vii) Salt-free diet with restricted fluid intake, (viii) Diuretics. 58 Vestibuiar nuclei \ Dorsal cochlear nerve \ Utricle Ampulla of semicircular canal The acoustic nerve and its connections Temporal lobe of cerebral cortex Dorsal cochlear nucleus Inferior cerebellar peduncle Ventral cochlear nucleus Cochlear nerve entering at level of upper medulla Superior olivary nucleus Trapezoid body The auditory system. The important point to observe is that this system is represented bilaterally in the cerebral cortex Auricular br. of vagus Tympanic branch Spinal part of accessory nerve Glossopharyngeal nerve Pharyrigeal nerve Recurrent laryngeal nerve Sup. laryngeal nerve The Glossopharyngeal, Vagus & Accessory Nerves Taste | General Sensation Sensovy Innervation of the Tongue (B) Surgical: (i) Dividing the vestibular nerve. (iii) Endolymphatic subarachnoid shunt. (ii) Ultrasonic irradiation, (iv) Removal of the utricle. IX. - THE GLOSSOPHARYNGEAL NERVE Anatomy: 1 . Sensory fibres : end in the nucleus of the tractus solitarius and the dorsal nucleus of the vagus. They carry sensations from the posterior third of the tongue, the tonsils and the pharynx. 2 . Taste fibres : end in the dorsal nucleus of the nerve in the medulla which gives fibres to the thalamus and then to the lowermost part of the sensory cortex. They convey taste from the posterior third of the tongue. 3 . Secetory fibres to the parotid gland. 4 . Motor fibres : arise in the inferior salivary nucleus and in the nucleus ambiguus. They supply the stylopharyngeus muscle. The 9th nerve crosses the posterior fossa, emerges through the jugular foramen to descend in the neck between the internal carotid artery and the internal jugular vein, then between the internal and external carotid arteries. Glossopharyngeal Neuralgia: It resembles trigeminal neuralgia, but pain starts in the tonsillar fossa, back of throat and larynx and may radiate to the ipsilateral ear. It is precipitated by swallowing or by protruding the tongue . Its cause is unknown. Treatment: (1) Carbamazepine (Tegretol) 200 mg. t.d.s. (2) Surgical division of the affected nerve in the posterior fossa. TASTE SENSATION Four tastes are known : (i) Sweet (ii) Salt (iii) Bitter, and (iv) Acid. Pathways: " *. 1 . Taste fibres from the anterior 2 thirds of the tongue pass in the lingual nerve —> Chorda tympani -> facial nerve —> geniculate ganglion —» nervus intermedius -> pons. 2 . Taste fibres from the posterior third of the tongue, the pharynx and the lower border of the soft palate are carried by the 9th nerve (glossopharyngeal). 3 . On reaching the pons, taste fibres enter the tractus solitarius —> nucleus of the tractus solitarius -> New fibres that cross the midline -> gustatory lemniscus -> ascends to the thalamus -> cortical centre for taste in the lowermost part of the sensory cortex. Ageusia : Loss of taste. Causes of Ageusia: (i) Lesions interrupting the pathways of taste fibres, (ii ) Post-traumatic ageusia: after head injury, (iii) Bilateral thalamotomy for treatment of parkinsonism. N.B.: Gustatory hallucinations may occur with olfactory hallucinations in irritative lesions of the uncus. X. - THE VAGUS NERVE Anatomy : It consists of sensory and motor fibres. 1 . Sensory fibres : (i) Somatic sensory fibres : end in relation with the spinal tract of the 5th nerve and its nucleus. They supply common sensibility to a part of the external ear. (ii) Visceral sensory (afferent) fibres : end in the nucleus of the tractus solitarius and 59 the dorsal nucleus of the vagus. They convey visceral sensations from the pharynx, larynx; trachea, oesophagus and thoracic and abdominal viscera. 2. Motor fibres : arise from 2 nuclei in the medulla: (i) The nucleus ambiguus : gives motor fibres to the striated muscles of the palate, pharynx, and larynx, (ii) The dorsal nucleus of the vagus : gives fibres to the parasympathetic ganglia of the vagal plexuses, innervating the thoracic and abdominal viscera. The vagus nerve leaves the skull through the jugular foramen to enter the neck, where it lies behind the carotid arteries and the internal jugular vein. It enters the thorax behind the large veins. The two vagi enter the abdomen via the oesophageal opening of the diaphragm to supply the abdominal viscera. The main branches of the vagus nerve : 1. A meningeal branch : innervates the dura mater of the posterior fossa. 2 . An auricular branch : supplies common sensibility to the back of the auricle and external acoustic meatus. 3 . A pharyngeal branch : supplies motor fibres through the pharyngeal plexus for the muscles of the pharynx and soft palate except the stylopharyngeus and the tensor veli palatini. 4 . Superior laryngeal nerve : gives two branches: (/) The internal laryngeal branch : is the sensory nerve of the larynx. (ii) The external laryngeal branch : innervates the inferior constrictor of the pharynx and the cricothyroid muscles. 5 . Cardiac branches. 6 . Recurrent laryngeal nerves (Rt & Lt): innervate all the muscles of the larynx (except the cricothyroid muscles) and also innervate the cricopharyngeus muscles which form the lower sphincter of the pharynx. Lesions of the Glossopharyngeal and Vagus Nerves : 1 . Unilateral pure motor paralysis : Poliomyelitis, diphtheria and botulism. 2 . Unilateral motor paralysis and sensory loss: Syringobulbia, vascular lesions in the medulla, posterior fossa tumours, trauma, tumours or enlarged glands at the jugular foramen . 3 . Bilateral C/.MJV. paralysis : * Double stroke (pseudobulbar palsy). * Motor neurone disease. 4 . Bilateral L.M.N. paralysis : * Poliomyelitis. * Progressive bulbar palsy . * Diphtheria and botulism 5 . Fatiguable motor paralysis : Myasthenia gravis . 6 . Palatal nystagmus : (Constant rhythmic vertical oscillation of the palate) e.g. due to a vascular lesion involving the central tegmental tract. CLINICALLY: (A) Lesions of the Glossopharyngeal Nerve (9th): result in : (/ ) Loss of taste and anaesthesia over the posterior third of the tongue. (ii) Sensory loss of the upper part of the pharynx with loss of the pharyngeal reflex (gag reflex). (B) Lesions of the Vagus Nerve (10th): result in : (/) Paralysis of the soft palate -> nasal speech and nasal regurgitation. (11) Paralysis of the pharynx —> dysphagia . (MI ) Paralysis of the larynx -* hoarseness of voice (total unilateral paralysis of one vocal cord) or aphonia (bilateral total paralysis of the vocal cords, both being immobile in mid-abduction), (iv) Loss of palatal and pharyngeal reflexes (gag reflex). 60 (C) Lesions of the Recurrent Laryngeal Nerve : (i) Unilateral: e.g. Mediastinum syndrome, enlarged cervical glands, cancer thyroid and operations on the neck . * This will result in unilateral abductor paralysis of one vocal cord,which remains in the midline. (ii) Bilateral: e.g. Enlarged cervical glands, goitre and trauma. This will produce bilateral abductor paralysis of the vocal cords, where both cords lie adducted together and are immobile on inspiration leading to respiratory obstruction. NB.: In unilateral palatal paralysis, the palate and uvula move up towards the normal side on phonation. Also in unilateral pharyngeal paralysis, the pharyngeal muscles move towards the normal side on phonation (curtain movement). XL -THE ACCESSORY NERVE Anatomy: * It is a purely motor nerve. * It consists of two portions : 1, The cranial portion arises from the nucleus ambiguus of the medulla, arises from the 2, The spinal portion anterior horn cells of the upper five cervical segments of the spinal cord. It ascends to enter the skull through the foramen magnum, joins the cranial portion to leave the skull through the jugular foramen, where the cranial portion joins the vagus to supply the pharynx and larynx. The spinal portion descends in the neck between the internal carotid artery and the internal jugular vein, to supply the sternomastoid and trapezius muscles. Lesions : may be . (a) Nuclear : e.g. poliomyelitis, motor neurone disease, polyneuritis, syringobulbia and tumours. (b) Infranuclear : e.g. tumours, syphilis, otitis media, cervical lymphadenitis, operations in the neck, polyneuritis, myasthenia gravis, myotonia atrophica and polymyositis. Clinically: 1 . A unilateral lesion : causes ipsilateral paresis or paralysis of the sternomastoid and upper part of the trapezius. 2 . A bilateral lesion : produces paralysis of both sternomastoids and both trapezii. Paralysis of the Eleventh Cranial Nerve (Spinal Accessory) 61 XIL - THE HYPOGLOSSAL NERVE Anatomy: * It is the motor nerve of the tongue. * It arises from the hypoglossal nucleus of the medulla. * Its fibres emerge from the ventral aspect of the medulla between the olive and pyramid. * It passes across the posterior fossa to leave the skull through the hypoglossal canal. * It descends in the neck, reaching the tongue by passing between the mylohyoid and hypoglossus muscles. * It gives a descending branch that joins the descending cervical nerve to form the ansa hypoglossis which innervates most of the infrahyoid muscles. * It gives another branch to supply the thyrohyoid muscles. Lesions : may be * U.M.N.L.: Unilateral or Bilateral. * L.M.N.L.: Unilateral or Bilateral. 1. Unilateral upper motor neurone lesions : e.g. Hemiplegia due to cerebrovascular accidents or deep - seated tumours. 2 . Bilateral U.MM.L. e.g. * Double stroke producing pseudobulbar palsy. * Motor neurone disease. 3 . Unilateral L.MM.L. e.g. * Syringobulbia. * Syphilitic meningitis. * Poliomyelitis. * Otitis media. * Brain-stem angiomas or tumours. * Periostitis of the hypoglossal canal. * Vertebral artery thrombosis or aneurysm. * Trauma, tumours, or enlarged glands high in the neck. 4 . Bilateral L.M.N.L. : e.g. * Motor neurone disease * Syringobulbia. * Retropharyngeal abscess. * Subluxation of the odontoid process. * Foramen magnum anomalies such as Arnold - Chiari malformation and basilar impression of the skull. Paralysis of the Tongue 62 Clinically: 1 . Unilateral U.MNJL. : causes deviation of the tongue to the opposite side of the lesion (hemiplegic side) on protrusion. 2 . Bilateral U.M.N.L. : causes a small, tight, spastic tongue lying in the floor of the mouth, with inability to protrude the tongue and dysarthria + Exaggerated jaw jerk. 3. Unilateral L.M.N.L. : causes paralysis of the corresponding half of the tongue, wasting with or without fasciculation and deviation of the tongue to the paralysed side on protrusion. 4 . Bilateral L.M.N.L. rleads to bilateral paralysis, wasting and fasciculation, with inability to protrude the tongue and dysarthria. 5 . Both UM.N.L. and L.M.N.L. may co - exist as in motor neurone disease, where pseudo and true (progressive) bulbar palsy coexist. Features 1 . Paralysis : Bilateral U.M.N.L. Spastic, tight, immobile 2 . Wasting : tongue. Small, tight tongue but no actual wasting 3 . Fasciculation : 4 . Jaw Jerk 5 .R.D.: Absent Exaggerated. Absent Features 1. Paralysis: 2 . Wasting : 3. Fasciculation: 4 . Jaw Jerk 5. R.D.: Bilateral U.M.N.L. Spastic, tight, immobile tongue. Small, tight tongue but no actual wasting Absent Exaggerated. Absent Bilateral L.M.N.L. Flaccid immobile tongue Wasted tongue with exaggerated longitudinal folds. Present Normal Present Bilateral L.M.N.L. Flaccid immobile tongue Wasted tongue with exaggerated longitudinal folds. Present Normal Present 63 CHAPTER 3 THE PYRAMIDAL SYSTEM ( CORTICOSPINAL TRACT ) Anatomy: The corticospinal (pyramidal) fibres are the axons of the Betz cells, large ordinary pyramidal cells and simple giant cells ofBrodmann's areas 4 and 6. They descend from the motor cortex, pass through the corona radiata to enter the internal capsule where they occupy the posterior one third of the anterior limb, the genu, and the anterior two - thirds of posterior limb. (The body is represented here as follows; head fibres in genu of internal capsule followed by upper limb fibres, trunk fibres and lastly lower limb fibres from before backwards). The pyramidal fibres reach the midbrain where they occupy the middle 3 fifths of the crus cerebri. They enter the pons where they become broken into scattered bundles by the transverse pontine fibres and the nuclei pontis. They reunite at the ponto - medullary junction to form the pyramids on the anterior aspect of the medulla. At the lower end of the medulla, each pyramidal tract divides into 3 parts : 1. The crossed pyramidal (corticospinal) tract: consists of the larger part that crosses in the " motor decussation" to descend in the lateral column of the spinal cord on the opposite side. 2 . The direct pyramidal (corticospinal) tract : consists of the smaller part that descends in the anterior column of the spinal cord on the same side. Its fibres gradually cross as they descend, ending at the mid - thoracic region. 3 . Uncrossed fibres : also remain in the lateral column, supplying the muscles of the trunk and respiration. All pyramidal fibres enter the grey matter of the spinal cord to end on the anterior born cells, either directly or through internuncial fibres. N.B.: The motor nuclei of the cranial nerves are all supplied by fibres from both pyramidal tracts and thus controlled by both cerebral hemispheres except the inferior part of the facial nuclei that innervates the lower half of the face, and the hypo glossal nuclei and rarely the mandibular nerve. These are only controlled by the opposite motor cortex. Function: The pyramidal tracts carry the nervous impuless which initiate voluntary movements from the motor cortex to the lower motor neurones in the brain-stem and spinal cord. Lesions: (A) Unilateral lesions at any level above the fifth cervical segment of the spinal cord produce Hemiplegia. (B) Bilateral lesions: 1. In the cerebral hemispheres : produce Pseudobulbar Palsy & Mental Symptoms. 2. In the brain-stem : produce Pseudobulbar Palsy. 3 .In the spinal cord: (a) In the cervical region : produce Quadriplegia (b) In the thoracic region: produce Paraplegia N .B.: The lower motor neurones (L.M.N.) consist of: (i) The motor nuclei of the cranial nerves in the brain-stem and the anterior horn cells of the spinal cord. (ii) The axons of these cells pass into the cranial nerves and the ventral roots of the spinal nerves. From the latter they pass to the peripheral nerves. Each LM.N innervates a bundle of 150 or more muscle fibres. 64 Motor Cortex Internal Capsule Midbrain Pons Medulla Lateral Corticospinal (crossed pyramidal) tract Ventral Corticospinal (direct pyramidal) tract Spinal Cord The Pyramidal System Lesion HEMIPL EGIA Rotation of the head toward the lesion Conjugate ocular deviation toward the lesion 1 U.M.N. facial palsy 12 th nerve palsy ( Aphasia only occurs with left sided lesions ) deviation of lower jaw toward hemiplegic side Hemiplegic posture Abdominal reflexes i or lost Weakness or paralysis of one side of the body (skilled movements are most affected ) Hemianaesthesia Cremasteric reflex I or lost Spasticily of clasp knife Type Hyperreflexia ± ankle clonus Ciicumdu ction gait Extensor plantar response (Babinski 's sign) U.M.N.L. Features L.M.N.L. 1. Paralysis or Unilateral lesions above the pyrami- Paralysis or paresis of the muscles paresis 2. Wasting 3. Muscle tone 4. Reflexes 5. Babinski's dal decussation produce paralysis on the opposite side, while those below the decussation prodyce paralysis on the same side of the lesion Absent (disuse atrophy may occur after prolonged paralysis) Hypertonia (spasticity) Hyperreflexia (exaggerated deep tendon jerks). Present (extensor plantar response) sign 6. Fasciculation Absent. 7. Trophic Absent changes 8. Reaction of Degeneration 9. E.M.G. supplied by the affected L.M.N. Present Hypotonia (Flaccidity) Hyporeflexia or areflexia Absent May be present Often present e.g. coldness, cyanosis and brittle nails in the paralysed limb (due to disuse and vasomotor paralysis) Present Absent „ No evidence of L.M.N.L. Evidence of L.M.N.L. HEMIPLEGIA DEFINITION: Hemiplegia : means paralysis of one side of the body due to a unilateral corticospinal (pyramidal) lesion at any level between the motor cortex and the fifth cervical segment. Crossed hemiplegia rmeans cranial nerve palsies on one side with hemiplegia on the contralateral side of the body. It results from brain-stem lesions. CAUSES OF HEMIPLEGIA : (A) Functional or Hysterical hemiplegia. (B) Organic: 1 . Congenital: e.g. Cerebral palsy. 2. Traumatic: (a) Immediate post-traumatic hemiplegia may occur due to: i. Epidural or intracerebral haemorrhage. ii. Cerebral contusion or laceration. (b) Delayed post-traumatic hemiplegia may occur due to : i. Chronic subdural haematoma. ii. Post-traumatic cerebral atrophy, iii. Post-traumatic cicatrisation. 65 3 . Inflammatory : e.g. Meningitis, Encephalitis, Syphilis, or Brain abscess. 4 . Neoplastic: e.g. Brain tumours, whether primary such as meningiomas and gliomas, or metastatic. 5 . Degenerative or Demyelinating :e.g. (a) Multiple sclerosis (M.S.). (b) Disseminated encephalomyelitis (D.E.M.). 6. Vascular lesions : are the commonest cause of hemiplegia. They include the following.: (a) Cerebral Thrombosis: secondary to: i. Disease of the vessel wall such as : * Cerebral arteriosclerosis. * Syphilitic endarteritis. * Periarteritis nodosa. ii. Disease of the blood such as : * Polycythemia vera. '* Profound anaemia. Hi. Circulatory disorder such as : * Systemic hypotension and slow circulation. * Myocardial infarction. Thrombotic hemiplegia usually occurs during sleep. (b) Cerebral Embolism :The embolus may come from : Hem/pteg/a and Hem/pares/s i. The heart & great vessels e.g. in : * Atheroma of the carotid, vertebral, innominate, subclavian arteries or the aorta. * Rheumatic heart disease, mitral stenosis and A.F. * Bacterial endocarditis (detached vegetations). * Congenital heart disease. * Myocardial infarction. ii. The Lung : e.g. in : * Bronchogenic carcinoma (metastatic emboli). * Suppurative lung syndrome e.g. lung abscess. iii. Peripheral vessels e.g: * Pelvic thrombophlebitis. * Femoral thrombophlebitis. iv. Other Emboli : e.g. Fat embolism, air embolism, parasitic emboli and malignant emboli. (c) Cerebral Haemorrhage: i. Combination of hypertension and cerebral arteriosclerosis. //. Ruptured intracranial aneurysm or angioma. iii. Haemorrhagic blood disease e.g. purpura. iv. Strain of whooping cough. v. Head injury. vi. Arsenical poisoning. (d) Hypertensive encephalopathy: Transient protective spasm of the cerebral arteries occurs in malignant hypertension and may lead to hemiplegia (temporary or permanent) due to ischaemia or thrombosis occurring on top of spasm. (e) Lateral sinus thrombosis : secondary to otitis media. 66 CLINICAL PICTURE: Onset: may be: (i) Sudden : e.g. in embolism and haemorrhage. (ii) Rapid : e.g. in thrombosis, haemorrhage, meningitis, encephalitis and hysteria. (iii) Gradual: e^ LahraiatiL(mur£7htaia and hysteria. Course rmaybe: (i) Regressive : e.g. in vascular lesions (thrombotic and embolic) and in infective lesions. (ii) Progressive : e.g. in neoplastic and degenerative lesions, (iii) Remittent : e.g. in M.S. Symptoms and Signs: I. - Motor Power :A pyramidal lesion results in : (A) Negative Signs : paralytic manifestations are due to loss of the corticospinal control. (B) Positive Signs: appearance of new phenomena e.g. muscular hypertonia and extensor plantar response. These are release phenomena due to the liberation of intact parts of the nervous system from the control of the pyramidal system. (A)Negative Signs: 1. Conjugate ocular deviation towards the side of the lesion due to transitory paralysis of centre. 2 . Rotation of the head towards the side of the lesion (transitory). 3 . Upper motor neurone facial palsy on the side of hemiplegia with paralysis of voluntary movements of the lower part of the face, while emotional movements as smiling and crying and associated movements as involuntary retraction of the angle of the mouth on voluntary closure of the eyes, are spared. 4 . Deviation of the tongue towards the hemiplegic side on protrusion. 5 . Deviation of the lower jaw towards the hemiplegic side on opening the mouth, due to paralysis of the mandibular nerve on that side. 6 . Weakness of the palatal movements on the side opposite the lesion,with deviation of the uvula towards the lesion. 7 . Paralysis or paresis of the upper and lower limbs on the side opposite the lesion. The finer and more skilled movements are more affected than the grosser and less skilled. Therefore, buttoning, sewing and playing the piano become clumsy. The extensors of the upper limb are more affected than flexors and the reverse occurs in the lower limb. 8 . Respiratory Movements : more expansion of the paralysed side of the chest occurs during quiet breathing, but the opposite occurs during forced breathing . 9 . Circumduction Gait: Swinging the paralysed leg outwards at the hip,with extension at the knee and plantar flexion of the foot and toes. (B) Positive Signs: 1 . Muscular Hypertonia (Clasp Knife Spasticity ) : Acute lesions e.g. vascular or infective are followed immediately by flaccidity of the paralysed limbs due to neural shock. After2 or 3 weeks, gradual return of tone and ultimately hypertonia occurs. In the upper limb : the adductors and internal rotators of the shoulder, flexors of the elbow, wrist and fingers and the pronators of the forearm are more spastic than their antagonists. In the lower limb :the adductors of the hip, extensors of the hip and knee, plantar flexors of the foot and toes are more spastic than their antagonists. Contractures may develop in the spastic muscles. 2 . Hemiplegic Posture : Is determined by the hypertonic (spastic)muscles. So the arm is adducted and 67 internally rotated, the elbow, wrist, and fingers are flexed and the forearm is pronated, while the lower limb is extended at the hip and knee, with plantar flexion and inversion of the foot 3. Reflexes: (a) Deep reflexes : are exaggerated after recovery from the shock stage and clonus may be present. (b) Superficial abdominal and cremasteric reflexes are diminished or lost on the hemiplegic side. (c) Extensor plantar response (Babinski sign) on the hemiplegic side. II - Sensations : Hemianaesthesia on the hemiplegic side may occur due to affection of the sensory fibres. HI - Speech: Aphasia or dysphasia may occur in left-sided lesions, in right-handed people. LOCALIZATION OF LESIONS OF THE PYRAMIDAL TRACT IN HEMIPLEGIA (A) Cortical Lesions (Cortical Hemiplegia): 1 . Monoplegia rather than hemiplegia. 2 . Cortical sensory loss in the paralysed limb occurs if the sensory cortex is involved . 3 . Jacksonian convulsions on the affected side of the body, which may become bilateral with loss of consciousness. 4 . Aphasia may occur in left-sided lesions. 5 . Coma may occur at athe onset. 6 . Homonymous hemianopia may occur in parieto- occipital lesions. (B) Subcortical Lesions (Subcortical Hemiplegia): 1. Hemiplegia with predominent weakness in one limb 2.Cortical hemi-anaesthesia on the hemiplegic side, due to affection of thalamo-cortical sensory fibres. 3.Crossed homonymous hemianopia, due to involvement of the optic radiation. (C) Capsular Lesions (Capsular Hemiplegia): 1.Complete hemiplegia. 2. Hemianaesthesia on the hemiplegic side. 3. Homonymous hemianopia may occur. 4. No coma, convulsions or aphasia. (D) Midbrain Lesions: 1. Weber's syndrome: * Ipsilateral third nerve paralysis (ophthalmoplegia). * Contralateral hemiplegia. 2. Benedikt's syndrome: * Ipsilateral third nerve paralysis. * Contralateral hemiplegia, hemianaesthesia and involuntary choreiform movements. (E) Pontine Lesions: 1. Millard-Gubler's syndrome: * Ipsilateral L. M. N. 6th and 7th nerve palsies. * Contralateral hemiplegia. * Ipsilateral paralysis of the jaw muscles may occur (5th nerve palsy). 2. Foville's syndrome: * Paralysis of conjugate ocular deviation to the side of the lesion. * Contralateral hemiplegia. * Ipsilateral L.M.N. facial palsy may be present * Ipsilateral paralysis of the jaw muscles may occur. N.B.: Homer's syndrome; fifth nerve palsy (motor & touch); trigemino-thalamic tract, spinothalamic tract, medial lemniscus & pyramidal tract affection; hyperyrexia and pinpoint puplis may occur in pontine lesions. 68 (F) Medullary Lesions (Medullary Hemiplegia): 1. Central medullary lesion : causes bilateral hemiplegia due to affection of the pyrami dal decussation. 2. Lateral medullary lesion: * Ipsilateral paralysis of the tongue, soft palate and vocal cord. * Ipsilateral horner's syndrome. * Ipsilateral trigeminal analgesia and thermo-anaesthesia. * Ipsilateral cerebellar ataxia. * Contralateral hemianaesthesia and hemiplegia. (G) Spinal Hemiplegia: is due to hemisection of the spinal cord (traumatic or extramedullary compression). It presents with the Brown-Sequard syndrome : l.At the level of the lesion: (a) L. M. N. paralysis due to damage of the anterior horn cells at the level of the lesion. (b) Loss of all sensations due to damage of the posterior horn at the site of the legion. 2. Below the level of the lesion: (a) Motor paralysis (Hemiplegia) on the same side of the lesion (pyramidal tract affection). (b) Deep sensory loss on the same side of the lesion (posterior column affection). (c) Loss of pain and temperature sensations on the opposite side (damage of the crossed spinothalamic tract). (d) Touch is relatively preserved on both sides. PSEUDOBULBAR PALSY Definition : Bilateral supranuclear paralysis of the bulbar muscles, usually associated with emotional incontinence and/ or spastic quadriparesis due to interruption of the corticospinal and corticobulbar tracts. Causes: 1. Heredofamilial: e.g. Juvenile motor neurone disease. 2. Inflammatory lesions e.g. D.E.M. & G.PJ. (General paralysis of the insane). 3. Vascular lesions e.g. (i) Double stroke (bilateral hemiplegia). (ii) Vertebro-basilar insufficiency, (iii) Cerebral arteriosclerosis, (iv) Syphilitic cerebrovascular disease. 4. Demyelinating lesions: e.g. M.S. 5. Degenerative lesions e.g. M.N.D. (motor neurone disease). 6. Neoplastic lesions: e.g.: Brain-stem gliomas. 7. Idiopathic: e.g. Cortico-striato-spinal atrophy (pseudosclerosis). Clinically: 1. Onset: is sudden in vascular lesions and gradual in neoplastic and degenerative lesions. 2. Bulbar Manifestations (due to supranuclear lesion of the 9th, 10th and 12th cranial nerves). (i) Dysarthria, slurred, spastic or nasal type of speech, (ii) Dysphagia: difficulty in swallowing, (iii) Hoarseness of voice, or aphonia, (iv) Nasal regurgitation of fluids. No wasting or fasciculation in the muscles of the palate and tongue. 69 3. Emotional lability or incontinence: Bouts of uncontrolable laughing and crying of sudden onset and sudden cessation with no logic stimulus and discrepancy between the emotional experience and expression. 4. Exaggerated jaw jerk. 5. Quadriparesis or quadriplegia may be present. N.B.: Progressive bulbar palsy occurs in lower motor neurone lesions of the 9th, 10th and 12th cranial nerves. Differentiation Between Pseudobulbar and Progressive Bulbar Palsies Emotional lability 70 CHAPTER 4 CEREBROVASCULAR DISORDERS BLOOD SUPPLY OF THE BRAIN Arterial Supply of the Brain: The brain receives its arterial blood from 2 systems: the carotid and vertebro-basilar (2 internal carotids and 2 vertebrals) (A) The internal carotid artery is a branch of the common carotid. It enters the skull through the carotid canal to the cavernous sinus. It consists of 4 segments: cervical, intrapetrosal, intracavernous & supraclinoid, the last 2 segments are called carotid siphon. It gives the following main branches: (i) the ophthalmic artery. (ii) the posterior communicating artery. (iii) the anterior choroidal artery. (iv) the anterior cerebral artery and (v) the middle cerebral artery. The anterior cerebral artery : supplies the medial surface of the anterior 3/5 of the cerebrum. The middle cerebral artery : supplies the lateral surface of the anterior 3/5 of the cerebrum. (B) The two vertebral arteries (right and left) are branches of the subclavian arteries. They enter the skull through the foramen magnum. They unite at the lower border of the pons to form the basilar artery, which bifurcates at the upper border of the pons into the 2 posterior cerebral arteries (Rt. & Lt.) Each Vertebral artery gives: (i) a posterior spinal artery. (iii) a posterior inferior cerebellar artery. (ii) an anterior spinal artery. (iv) a posterior meningeal artery. The Basilar artery gives: (i) the anterior inferior cerebellar artery. (ii) the labyrinthine arteries. (iii) Paramedian and circumferential pontine branches. (iv) the superior cerebellar artery & (v) the 2 posterior cerebral arteries. The vertebrobasilar system supplies the posterior 2/5 of the cerebrum, the brain - stem, the cerebellum and the spinal cord. (C) The Circle of Willis: is located on the base of the brain (inferior surface). This circle is formed by the anastomosing branches of the internal carotid arteries and the basilar artery. These are the anterior and posterior communicating arteries, the anterior, middle and posterior cerebral arteries. Each of the main cerebral arteries: anterior, middle and posterior, gives two types of branches: (a) the central or ganglionic branches. (b) the cortical or circumferential branches. The Central or Ganglionic arteries: Supply the diencephalon, basal ganglia and internal capsule Blood Supply of the internal capsule: (i) The striate branches of the middle cerebral artery -> the superior half of the anterior and posterior limbs of the internal capsule, (ii) The medial striate artery (recurrent artery ofHeubner: a branch of A.C.A.) -»the inferior half of the anterior limb of the internal capsule. (in) The internal carotid -> one or more branches to the genu. 71 (iv) The posterior communicating artery -> the anteiror 1/3 of the ventral half of the posterior limb of the internal capsule. (v) The anterior choroidal artery -» the posterior 2/3 of the ventral half of the posterior limb of the internal capsule and its retrolenticular part. Venous Drainage of the Brain: Fine branches -> a pial plexus -> cerebral veins (superficial and deep) -> The sinuses of the dura mater —»The internal jugular vein. A - Venous Sinuses: The superior sagittal (longitudinal) sinus : lies along the attached border of the falx cerebri. The inferior sagittal (longitudinal) sinus : lies along the free border of the falx. The sinus rectus (straight sinus) : lies along the line of attachment of the falx and tentorium. It is formed by the union of: * the inferior sagittal sinus & * the great cerebral vein of Galen. The 2 transverse sinuses: Each passses laterally and forwards —»internal jugular vein. The confluence of sinuses: is the point of union of the superior sagittal, straight and transverse sinuses, together with the unpaired occipital sinus. The cavernous sinus: is located on the side of the sphenoid bone, lateral to the sella and consists of a network of vessels enclosing the internal carotid, the 3rd, 4th, 6th and the ophthalmic division of 5th cranial nerves. It receives: * the basilar venous plexus. * the 2 ophthalmic veins via the orbital fissure. * the sphenoparietal sinus. It empties into: * the superior petrosal sinus -> transverse sinus & * the inferior petrosal sinus -»jugular vein. The circular sinus: is a venous ring around the hypophysis formed by: the 2 cavernous sinuses and their connecting channels. N.B.: The venous sinuses communicate with the extracranial veins by emissary veins which perforate the skull. B. The Cerebral Veins: They are divided into: 1. The Superficial Cerebral Veins: drain the cortex and subcortical medullary substance, into the superior sagittal sinus and basal sinuses (cavernous, petrosal & transverse). 2. The Deep Cerebral Veins: drain the deep medullary substance, basal ganglia and dorsal parts of the diencephalon, into the internal & great cerebral veins. The 2 groups are interconnected by both intracerebral and extracerebral anastomosis. N.,B.: The venous sinuses & cerebral veins are devoid of valves. CEREBROVASCULAR ACCIDENTS Cerebrovascular accidents fall into two groups : 1. Spontaneous intracranial haemorrhage: includes: (i) Primary intracerebral hemorrhage (20% of cases) (ii) Subarachnoid hemorrhage (8 % of cases) 2. Cerebral infarction or ischaemia : is caused by : (i) Cerebral embolism (20% of cases) e.g. in A.F., myocardial infarction & bacterial endocarditis. 72, Median surface Middle cerebral artery 1. OrbitofrontaJ artery 2. Prerolandic artery 3. Rolandic artery 4. Anterior parietal artery 5. Posterior parietal artery 6. Angular artery 7. Posterior temporal artery 8. Anterior temporal artery 9. Orbital artery 10. Frontopolar artery 11. CallosomarginaJ artery \2. Posterior internal frontal artery 13. PericaUosal artery- Scheme of the artenaJ supply of the cerebraJ cortex. (Redrawn and reproduced, with permjssion, from B Intracranial Tumors. 2nd ed. Thomas. 1948 ) Anterior limb Posterior limb Blood Supply of the Internal Capsules: Anterior cerebral arteries Anterior communicating artery Middle cerebral arteries Circle of Willis Internal carotid arteries Posterior communicating arteries Posterior cerebral arteries Basilar artery Vertebral arteries The blood supply to the brain and the cirde of Willis. (ii) Cerebral thrombosis (50% of cases) (iii) Cerebral arteriosclerosis and hypertension (iv) Other causes include: * Anaemia. * Hypoxia e.g. cardiac arrest, CO poisoning, & pulmonary emboli. * Vasospasm e.g. migraine & following subarachnoid hemorrhage * Micro-emboli (platelets, cholesterol, or fibrin). * Hypotensive states causing cerebral ischaemia. * Reversal of cephalic blood flow (subclavian steal syndrome). * Pregnancy leading to increased coagulability of blood. * Dehydration leading to haemoconcentration. * Arteritis e.g. collagen vascular disease. * Dissecting aortic aneurysm involving the carotid artery. * Ligation of carotid artery for intracranial aneurysm. Emmissary veins Inferior sagittal sinus Cavernous sinus Great cerebral vein Frontal vein .Rectus sinus Transverse Ophthalmic veins Pterygoid plexus Anterior facial vein Internal jugular vein sinus Superior petrosal sinus Inferior petrosal sinus Occipital vein Deep cervical vein Superior sagittal sinus The dural venous sinuses 73 CEREBRAL HAEMORRHAGE Aetiology: It may be arterial, capillary, or venous. 1. Arterial intracerebral haemorrhage is caused by: (i) Arteriosclerosis: hypertrophy and degeneration of the media with atheroma of the intima, as well as miliary aneurysms (micro-aneurysms). (ii) Hypertension: Usually in primary hypertension. (Hi) Other causes include: developmental vascular anomalies/leukaemia, polyarteritis nodosa and septic embolus in bacterial endocarditis. 2. Capillary orpetechial haemorrhages may occur in: (i) Acute encephalitis. (ii) Septicaemia. (iii) Severe anaemia (iv) Leukaemia. (v) Thrombocytopenic purpura. (vi) Anaphylaxis. (vii) Haemorrhage into a brain tumour e.g. glioma. 3. Intracranial venous haemorrhage is met with in: (i) Whooping cough. (ii) Pyaemia. Pathology: * It may affect any part of the brain e.g. the internal capsule, pons, ventricles, or cerebellum. * The resultant blood clot may remain encapsulated, or open into one lateral ventricle or into the subarachnoid space. * Compression and oedema of the brain tissue surrounding the clot. * Absorption of the clot with gliosis and phagocytosis of the destroyed brain tissue may occur. Clinical Picture: Age : It is common in late middle age. Sex : It affects males more than females. Onset: Sudden, abrupt, or apoplectic. Premonitory Symptoms include: (i) Headache (ii) Vomiting (iii) Dizziness. (iv) Vertigo (v) Syncope. (vi) Confusion. (vii) Epistaxis. (viii) Transient monoparesis and/or dysphasia. Precipitating Factors: include mental excitement and physical effort Presenting Symptoms include: 1. Sudden severe headache and vomiting. 2. Loss of consciousness, with or without convulsions. 3. Focal signs depending on the site and size of haemorrhage: I. Capsular Haemorrhage: 1. Coma. 2. Rotation of the head and deviation of the eyes towards the side of the lesion. 3. Contralateral flaccid hemiplegiaf with flattening of the nasolabial fold, puffing of the cheek during expiration, hypotpnia, hyporeflexia or areflexia, lost abdominals and extensor plantar response. Spasticity develops after 2-3 weeks. 4. Contralateral hemianalgesia: Anaesthesia to pin prick. 5. Pulse: Full, bounding, slow pulse. 6. Temperature: Slight pyrexia. 7. Respiration: Deep stertorous respiration or Cheyne-Stokes respiration. 8. B.P.: usually raised. 9. Eyes: * Pupils: unequal. * Corneal reflex: is lost on the hemiplegic side or bilaterally. 74 * Fundus: Arteriosclerotic retinal vessels with or without slight papilledema. * Divergent squint may be present 10. Sphincters: Retention or incontinence of urine and faeces. nPontine Haemorrhage: l.Coma. 2. Unilateral pontine haemorrhage results in ipsilateral facial palsy with contralateral hemiplegia. 3. Bilateral pontine haemorrhage produces quadriplegia with bilateral facial palsy and bilateral extensor plantar response. 4. Decerebrate rigidity. 5. Pinpoint pupils due to bilateral damage of the ocular sympathetic fibers. 6. Poikilothermia: hyper or hypothermia due to loss of the hypothalamic contol over the body temperature. HI- Ventricular Haemorrhage: 1. Deep coma 3. Rigid extension of the upper limbs. 2. Bilateral pyramidal lesion. 4. Hyperpyrexia. IV- Cerebellar Haemorrhage: 1. Onset is sudden with occipital headache, vomiting and vertigo. 2. Paralysis of conjugate gaze towards the lesion, 6th nerve palsy or skew deviation may be present. 3. Ataxia: usually trunkal. 4. Coma may occur due to brain - stem compression. Investigations: 1. CT scan of the brain localizes the hemorrhage 2. Angiography or ventriculography may be indicated to localize the site of the clot 3. C.S.F.: Lumbar puncture carries the risk of tentorial or cerebellar herniation so it is only done if necessary for diagnosis. CSF shows increased proteins, raised pressure ± blood or RBCs. 4. Heart is enlarged from chronic hypertension. 5. Urine; albuminuria and glycosuria. Differential Diagnosis: Intracerebral haemorrhage has to be distinguished from: 1. Cerebral thrombosis or atheroma. 2. Cerebral embolism. 3. Primary subarachnoid haemorrhage. 4. Intracranial tumour. 5. GPI and meningovascular syphilis. Prognosis: * Death occurs in most cases within few hours to few days. * Causes of death include: medullary anaemia, increased ICT, destruction of brain tissue, and intercurrent infection e.g. pneumonia which may occur during coma. * Bad prognosis is expected in: (i) Bilateral paralysis of limbs. (ii) Bloody C S F. (iii) Deep coma continuing more than 48 hours. * Few patients recover from coma with permanent disability e.g. impaired intelligence, speech and memory, irritability, emotional instability, hemiplegia, hemianaesthesia, hemianopia, thalamic pain, and/or extrapyramidal involuntary movements such as chorea, athetosis or Parkinsonian tremors. Treatment: (A) Conservative: 1. The patient should be moved as little as possible. 2. Nursing care. 3. Steroids to reduce cerebral oedema. 75 4. Avoid hypotensive drugs, as they may aggravate the condition. (B) Surgical evacuation of the clot is indicated in young patients after localization by CT scanning, angiography or ventriculography. SUBARACHNOID HAEMORRHAGE (S.A.H.) Aetiology: 1. Ruptured intracranial aneurysm is the commonest cause. (85%) 2. Ruptured intracranial angiomatous malformations. (10%) 3. Other causes include: (i) Head injury. (ii) Acute encephalitis or encephalopathy with capillary damage and haemorrhage. (iii) Haemorrhagic diseases. (iv) As a complication of anticoagulant therapy. (v) Intracranial tumours e.g. angioblastic meningioma, glioma, metastatic melanoma and other metastases. (vi) Cheese syndrome (acute hypertensive reaction) : in patients ingesting cheese while receiving one of the amine-oxidase inhibitor drugs, (vii) Cerebral atheromatosis with hypertension, (viii) Angioma of the spinal cord. Clinical Picture : 1. Age : 2nd and 3rd decades in angioma, 4th and 5th decades in aneurysm. 2. Sex : both sexes, but females more than males. 3. Increased ICT: (i) Severe headache. (ii) Vomiting. (iii) Slight papilloedema. (iv) Convulsions. (v) Deep coma with irregular breathing and slow pulse may occur or the patient may be only confused. (vi) Retinal haemorrhages, subhyaloid or vitreous haemorrhages may occur, (vii) Hyporeflexia or areflexia, lost abdominals and extensor plantar responses, (viii) Hyperpyrexia, transient arterial hypertension, albuminuria and glycosuria may occur due to hypothalamic damage. 4. Meningeal Irritation (Meningism): (i) Neck rigidity. (ii) Positive Kernig's sign. (iii) Opisthotonos may occur. (iv) Low backache and pain in the back of the neck. 5. Focal Symptoms : (due to compression by a blood clot, cerebral haemorrhage, or in farction). (i) Visual field defect. (ii) III, IV & VI cranial nerve palsies, (iii) Frontal lobe haemorrhage produces mental symptoms, hemiparesis, and motor aphasia in left-sided lesions. (iv) Convulsions and monoplegia (middle-cerebral), (v) Crossed homonymous hemianopia (posterior cerebral), (vi) Quadriplegia or crossed hemiplegia (basilar artery), (vii) Spinal subarachnoid haemorrhage; gives low back pain and pain in lower limbs, sphincteric disturbances, stiffness of the spine, Kernig's sign, flaccid weakness of the L.Ls. with anaesthesia and areflexia. 6. Cranial signs: e.g. cranial bruit, angioma of the face and pulsating exophthalmos. 76 Differential Diagnosis of Cerebrovascular Disorders Features Intracerebral Heamorrhage Cerebral Thrombosis Cerebral Embolism Subarachnoid Haemorrhage Age Common between 40 & 50 years Common over 50 years Any age, but common below 40 2 nd & 3rd decades in angioma 4th & 5 th decades in aneurysm. Onset Dramatic & apoplectic. Rapid, over minutes to Generally during activity. hours. Unrelated to activity Sudden within seconds or minutes. May be ushered by convulsions. Unrelated to activity Sudden onset of severe headache. Unrelated to activity. Prodromal Severe headache, vomitsymptoms ing, epistaxis & syncopy may accur Course Dizziness, aphasia, hemi- Usually no prodrome paresis & hemiparaesthesias, with improvement between attacks. Rapid hemiplegia & other Rapid improvement at phenomena e.g. convulse times ions over minutes to one hour Conscious- Rapid progression to ness deepening coma. Relatively preserved Recurrent stiff neck, headaches, Low back pain, ophthalmoplegia, convulsions & syncope Rapid improvement may accur Variable,worst in initial few days after onset Relatively preserved Relatively brief disturbance of consciousness. Differential Diagnosis (Cent.) Investigations: 1. CT Scan of the Brain discloses the S.A.H. in most cases. 2. Lumbar Puncture & CSF Examination are helpful provided no papilledema or lateralizing neurologic signs.CSF shows the following: (i) Red cells are present in the first week. (ii) Xanthochromia (yellow coloration of the supernatant fluid) for 2-3 weeks, (iii) Raised protein content. (iv) Mononuclear pleocytosis. (v) Paretic colloidal gold curve may be present. 3. Plain X - ray skull : may show calcified angioma, calcification in the wall of an aneurysm, abnormal vascularity, and erosion of bone. 4. Angiography: should be done except in very old people, severe shock, severe atheroma, or hypertension which make surgery impossible. Bilateral carotid angiography should be done, as multiple aneurysms may be present. Angiography is negative in about 25% of cases. Prognosis: (i) 40 to 50% of patients die within 8 weeks.Two thirds of them die within 24 hours from the first attack.The remaining one-third die from a second more serious attack usually in the second week after the first attack, (ii) 10% of the surviving patients die within 6 months, and another 10% die subsequently due to recurrent bleeding, (iii) Out of the long-term survivers (30%): 10% are symptom-free, 10% are disabled by hemiplegia, epilepsy, headache or psychoneurosis, and the remainder (10%) have minimal residual symptoms. Treatment: (A) Medical Treatment: is indicated in the acute phase, in multiple aneurysms or huge angioma and when aneurysm is surgically inaccessible. 1. Complete bed rest for 4 weeks at least. 2.Sedation and relief of headache e.g. by pethidine or morphine. 3. Prophylactic antibiotics to guard against respiratory and urinary infection. 4.Avoid straining and physical exertion 5. Dehydrating measures, e.g. Mannitol 20%, 1 gm/ kg wL i.v. over 15-20 min. & Dexamethasone, 4 - 8 mg i.v. 6 hourly. 6.Lumbar puncture. 7. Open bowels. 8. Treatment of coma as usual. (B) Surgical Treatment: The optimal time for operation is one week after the haemorrhage. 1. Carotid ligation is beneficial in posterior communicating artery aneurysms, but it may be complicated by hemiplegia. 2. Direct attack on middle cerebral artery aneurysms e.g. by excision of the aneurysmal sac or application of a surgical clip to its neck. CEREBRAL EMBOLISM Aetiology: Refer to vascular causes of hemiplegia CEREBRAL THROMBOSIS Aetiology: Refer to vascular causes of hemiplegia Management of Cerebral Ischaemia: (Cerebral Thrombosis and Embolism) (A) General Management includes: 1. Changing the position of the patient in bed every two hours. 2. Care of the skin: using alcohol and talc powder to guard against bed- sores. 77 3. Care of the bladder e.g. catheterization in cases of retention of urine. 4. Care of Respiration: (i) Suction of secretions (ii) Bronchoscopy. (iii) Tracheotomy is sometimes necessary. 5. Treatment of heart failure if present e.g. by digitalis and diuretics. 6. The patient's nutrition and electrolyte balance: Tube feeding or i.v. fluid therapy may be needed. 7. Paraldehyde 15-30ml. may be given in case of insomnia (B) Physiotherapy: 1. Keep the patient's limbs in the optimal position using sandbags. 2. Massage to improve the circulation in the paralysed muscles. 3. Short-wave or infra-red therapy. 4. Passive movements. 5. Active exercises. 6. Mobilization and rehabilitation. (C) Specific Therapy: 1. Anticoagulants: are most helpful for transient cerebral ischaemia (Transient is chaemic attacks). Completed stroke could not be helped by anticoagulant therapy. Indications. (i) Carotid T.I.As. (transient ischemic attacks) (ii) Vertebral-basilar T.I.As. (iii) Cerebral embolism, (iv) Deep thrombophlebitis with or without pulmonary embolism. Contra-indications: (i) Elderly patients (over 60). (ii) Severe hypertension. (iii) Blood diseases, (iv) Drugs potentiating oral anticoagulants e.g. salicylates, aspirin, butazolidin, dilantin, sulfisoxazole, tetracyclines, chloramphenicol, neomycin, quinidine, and chloral hydrate. (v) Uraemia, liver failure and shock. Anticoagulants include: (a) Heparin: S.C. : 7000 - 9000 U., 6-hourly. orl.V.: 5000-8000 U.,4-hourly. OR 10,000 U. every 6 hours, or I.V. infusion at a rate of 1000 - 1500 U /hr. * Lee-White clotting time or activated clotting time should be determined before initiating therapy (Normally 6-15 minutes ) and once every 24 hours. A good therapeutic effect is achieved when C.T. becomes 1.5-2 times the pretreatment value. * The Antidote for heparin is protamine sulfate 1% which is given in physiologic saline I.V. (1 mg. for each 100 U. heparin). (b) Oral Anticoagulants: Preparations Dosage 1st. day (i) Dicumarol 200 - 400 mg. 30 (ii) Warfarin - 50 mg. 200 (iii) Dindevan mg. 2nd. day Daily maintenance 100- 200 mg. 10- 15 mg. 100 mg. 100 mg. 7.5 mg. 50 mg. * A good therapeutic effect is achieved when the prothrombin time is 2 - 2.5 times the control. 78 * Barbiturates, doriden, meprobamate and griseofulvin reduce the anticoagulant effect of these drugs. * The Antidote for oral anticoagulants: is Vitamin K slowly I.V. + Transfusions of fresh citrated blood. * Usually we start with heparin and dindevan together for 48 - 72 hours, after which heparin is withdrawn and the patient is kept on a maintenance dose of dindevan, judged by prothrombin time values. * Many neurologists prefer to use heparin alone for 1 - 2 weeks, shifting to oral anticoagulants after 2-3 days of overlapping therapy. 2. Antiplatelet Therapy e.g. by Acetylsalicylic Acid (Aspirin ) &/ or Dipyridamole (Persantin ) may be used in TIAs after, a short course of conventional anticoagulation. 3. Vasodilators: e.g. papaverine HC1, nicotinic acid, hydergine, ... etc. are frequently prescribed but their value is doubtful. Moreover, they may cause "internal steal" due to dilatation of the relatively healthy cerebral vessels, diverting the blood away from the ischaemic area. 4. Correction of B.P. changes e.g. by hypotensive drugs in hypertension and by vasopressors in hypotension. 5. Other drugs : e.g. (i) Lipolytic agents e.g. clofibrate for atherosclerosis, (ii) Muscle relaxants for spasticity. (iii) Corticosteroids for cerebral oedema, (iv) Chlorpromazine for excitement, (v) Antidepressants for depression. 6. Treatment of the cause in cerebral embolism: e.g. A.F., or bacterial endocarditis. 7. Surgery: * It is hazardous in acute strokes as haemorrhage in the infarcted area is liable to occur. * It is also of no value in complete occlusion of the carotid or vertebral arteries. * Surgical correction is indicated in stenosis of the proximal carotid artery or of the vertebral artery that narrow the lumen more than 50% as shown by angiography. Thromboendarterectomy and a bypass graft are the well-known operative measures. HYPERTENSIVE ENCEPHALOPATHY Definition: An acute transient disturbance of cerebral function due to arterial hyperten sion of any cause, manifested clinically by convulsions and focal symptoms e.g. hemiplegia, aphasia, or blindness. Aetiology: Arterial hypertension e.g. in acute and chronic glomerulonephritis, eclampsia and malignant hypertension. This results in vasoconstriction of the cerebral arterioles, which causes the characteristic symptoms. Clinical Picture: 1. Onset: is subacute 2. Progressive headache. 3. Vomiting. 4. Convulsions. 5. Mental confusion or coma. 6. Aphasia. 7. Hemiparesis. 8. Blurring of vision or blindness. 9. Arterial hypertension. 10. Puffness of the face. 11. Bilateral papilloedema with or without hypertensive retinopathy may be present. 12. Neck rigidity, tachycardia and fever may be present. 13. EEC: shows diffuse slow activity with loss of the alpha rhythm and absence of the "following" response to photic stimulation. 79 14. CSF pressure: is increased. Differential Diagnosis: It must be distinguished from: 1. Uraemia 2. Brain tumour. 3. Meningitis. 4. Cerebrovascular strokes e.g. haemorrhage or thrombosis. Prognosis : is on the whole good and recovery is the rule, but severe and frequent convulsions are a bad sign. Treatment: 1. Hypotensive drugs e.g. Nifedipine (Adalat) sublingual or sodium nitroprus side(Nipride) i.v. infusion. 2. Dehydrating measures for brain oedema e.g. Dexamethasone (Decadron) i.v. & / or diuretics as i.v. frusemide (Lasix) or Mannitol 20% 1 gm/kg. body wt. i.v. over 15 20 min. 3. Barbiturates or paraldehyde i.m. for convulsions. 4. Treatment of the cause e.g. treatment of nephritis. SYNDROMES OF THE CEREBRAL ARTERIES INTERNAL CAROTID ARTERY OCCLUSIVE SYNDROMES: (A) Carotid Insufficiency : results in recurrent transitory attacks of: 1. Unilateral frontal headache. 2. Transient blindness in the ipsilateral eye. 3. Contralateral paraesthesiae or hemiparesis. 4. Convulsions 5. Confusion. 6. Aphasia or dysphasia. (B) Carotid Occlusion: 1. Ipsilateral blindness or blurring of vision (Ophthalmic artery occlusion) 2. Contralateral hemiplegia. 3. Contralateral hemi-anaesthesia (usually cortical). 4. Crossed homonymous hemianopia (temporal hemianopia in the opposite visual field). 5. Aphasia (sensory & motor) in left-sided lesions. 6. Carotid pulse may be diminished or lost and audible bruit may be present over a stenotic carotid artery. 7. Carotid angiography is diagnostic. N.B.: Coma may occur at the onset. MIDDLE CEREBRAL ARTERY OCCLUSIVE SYNDROMES : (A) Main Artery Occlusion : 1. 2. 3. 4. Coma at the onset. Contralateral hemiplegia most marked in the face, tongue & U.L. Contralateral hemianesthesia (cortical sensory loss). Crossed homonymous hemianopia (due to infarction of the optic pathways in the temporal lobe). 5. Global aphasia in left-sided lesion (dominant hemisphere). (B) Ganglionic Branches Occlusion (Lenticulooptic & Lenticulostriate): produces Capsular hemiplegia: 1. 2. 3. 4. 80 Complete hemiplegia on the opposite side. Hemianaesthesia (usually subcortical in type). Hemianopia may be present. Usually no coma, convulsions or aphasia. (C) Cortical Branches Occlusion : 1. Frontal branch occlusion : (i) Facio-ftrachial monoplegia. (ii) Motor aphasia in left-sided lesion. 2. Parietal branches occlusion : (i) Hemianesthesia. (ii) Receptive aphasia (Visual agnosia) and apraxia in left-sided lesions. 3. Temporal branches occlusion : (i) Receptive aphasia (Auditory agnosia) in left-sided lesion, (ii) Crossed homonymous hemianopia. ANTERIOR CEREBRAL ARTERY OCCLUSIVE SYNDROMES : (A) Main Trunk Occlusion : 1. Contralateral hemiplegia, L.L. is more affected than U.L. (due to infarction of the leg area in the motor cortex). 2. Contralateral cortical anesthesia in the L.L. (due to infarction of the leg area in the sensory cortex). 3. Mental confusion, in left-sided lesion. 4. Motor aphasia, in left-sided lesion. 5. Clouding of consciousness, in left-sided lesion. 6. Apraxia on the left side. 7. Forced grasping & groping reflexes on the paralysed side. (B) Heubner's Artery Occlusion : 1. Contralateral facio-brachial monoplegia, proximal more than distal, with sensory loss of the spinothalamic type. 2. Mental deterioration in left-sided lesion. 3. Motor aphasia in left-sided lesion (due to infarction of the subcortical white matter beneath Broca's area). (C) Paracentral Artery Occlusion : 1. Contralateral spastic monoplegia (L.L.) with or without cortical sensory loss (due to infarction of the leg area on the paracentral lobule). 2. Urinary incontinence. (D)Occlusion of Both Anterior Cerebral Arteries : e.g. by anterior communicating artery aneurysm 1. Dementia & apathy. 2. Long tract signs. 3. Bilaeral grasp reflexes may be present. ANTERIOR CHOROIDAL ARTERY OCCLUSIVE SYNDROME : 1. Hemiplegia. 2. Hemianesthesia. 3. Hemianopia. N.B.: This syndrome must be differentiated from middle cerebral artery ocelusive syn drome by the absence of coma & the better prognosis. POSTERIOR CEREBRAL ARTERY OCCLUSIVE SYNDROMES : (A) Main Trunk Occlusion : 1. Contralateral homonymous hemianopia with escape of the macular region. 2. Visual agnosia in left-sided lesion. 3. Thalamic syndrome. 4. Temporal lobe seizures may occur. (B) Thalamo-geniculate artery occlusion (Thalamic syndrome): 1. Temporary flaccid hemiparesis or hemiplegia. 2. Impairment of superficial & loss of deep sensation. 81 3. Thalamic pain or thalamic hyperpathia (spontaneous, agonizing burning pain). 4. Reflex dystrophy of the shoulder girdle & arm. 5. Choreo-athetoid movements, ataxia or tremor. All these manifestations occur on the opposite side of the lesion. (C) Thalamoperforationg artery thrombosis : results in choreo-athetoid movements of the opposite arm & leg (due to infarction of the termination of the dentato-rubro-thalamic pathway & subthalamic structures). (D) Cortical Branches Occlusion : 1. Occipital branches occlusion (Calcarine branches thrombosis) : Contralateral ho monymous hemianopia with macular sparing. 2. Parietal branches occlusion : Visual agnosia in left-sided lesion. VERTEBROBASILAR ARTERY OCCLUSIVE SYNDROMES : (A) Vertebrobasilar Insufficiency: 1. Syncope or drop attacks (transient loss of postural tone). 2. Ophthalmoplegia & diplopia. 3. Vertigo, nausea, vomiting & deafness (internal auditory artery occlusion). 4. Ataxia. 5. Nystagmus. 6. Bilateral pyramidal signs with bulbar palsy. 7. Bilateral dysesthesiae. 8. Migraine-like attacks or visual hallucinations may occur. (B) Basilar Artery Occlusion : 1. Deep coma. 2. Small pupil fixed to light 3. Unilateral or bilateral 3rd , 4th & 6th nerve palsies. 4. Pseudobulbar palsy &quadriplegia with decerebrate rigidity. 5. Rapidly fatal (death usually occurs in 2 to 5 days). (C) Paramedian Branches Occlusion (Crossed hemiplegias): 1. In the midbrain : (i) Weber's syndrome : (infarction of tthe oculomotor nucleus & cerebral peduncle). * Ipsilateral 3rd nerve palsy (ophthalmoplegia). * Contralateral hemiplegia. (ii) Benedikt's syndrome : (infarction of the oculomotor nucleus, cerebral peduncle, medial lemniscus & red nucleus) * Ipsilateral ophthalmoplegia. * Contralateral hemiplegia, hemianesthesia, & choreiform movements. 2. In the pons : (i) Millard-Gubler's syndrome : * Ipsilateral 6th & 7th nerve palsies. * Contralateral hemiplegia. (ii) Foville's syndrome: * Ipsilateral L.M.N facial palsy. * Paralysis of the conjugate gaze to the side of the lesion. * Contralateral hemiplegia. 3. In the medulla oblongata : (Infarction of the 12th nerve nucleus, the pyramid & the medial lemniscus). * Paralysis & atrophy of the homolateral half of the tongue. * Contralateral hemiplegia & hemianesthesia. (D) Cortical Branches Occlusion: 1. Posterior cerebral occlusive syndromes: were discussed before. 2. Cerebellar Arteries Occlusion: (i) Superior Cerebellar Artery Occlusive Syndrome: 82 (a) Ipsilateral: * Choreiform movements (due to damage to the brachium conjunctivum). * Homer's syndrome. * Deafness may occur. * Facial palsy may occur. (b) Contralateral: analgesia & thermo-anesthesia (due to damage of the trigeminothalamic & spinothalamic tracts). (ii) Anterior Inferior Cerebellar Artery Occlusion: (a) Ipsilateral: * Cerebellar ataxia. * Horner's syndrome (due to damage of the descending sympathetic fibres). * Deafness (8th). * Facial palsy (7th). * Loss of touch sensibility in the face (main sensory nucleus of 5th nerve nerve). (b) Contralateral: analgesia & thermo-anesthesia. (iii) Posterior Inferior Cerebellar Artery Occlusion: (Wallenberg's syndrome or Lateral Medullary syndrome) (a) Onset: with severe vertigo, hiccup, vomiting, dysphagia & pain or paraesthesiae over the face. (b) Ipsilateral: * Cerebellar ataxia. * Nystagmus (due to damage of the vestibular nuclei). * Horner's syndrome. * Dissociated sensory loss over the face (due to damage of the spinal tract & nucleus of the 5th nerve). * Dysarthria & dysphagia due to weakness of the homolateral palatal muscles (damage of the nucleus ambiguus of the vagus). (c) Contralateral : analgesia & thermo-anesthesia (due to damage of the spinal lemniscus). 3. Spinal Artery Occlusion : (i) Thrombosis of the anterior spinal artery may occur due to atherosclerosis & produces massive infarction of the spinal cord with a complete flaccid paraplegia, retention of urine and sensory loss to pain and temperature below the level of the lesion with preservation of touch and proprioceptive sensations (posterior column). Complete quadriplegia with respiratory paralysis and death occur in upper cervical lesions, (ii) Embolism or occlusion of radicals of the anterior spinal artery produces incomplete infarction with paraparesis. (iii) Intermittent claudication (ischaemia) of the spinal cord or of the cauda equina may follow exertion and relieved by rest. Radiography and myelography may show bony stenosis of the spinal canal or a central disc protrusion in these cases. Laminectomy and decompression improve the condition. 83 CHAPTER 5 HYDROCEPHALUS ANATOMY : THE VENTRICLES AND CSF CIRCULATION There are 4 ventricles in the brain - 2 lateral ventricles, - the third ventricle & - the fourth ventricle. The 2 lateral ventricles are the cavities of the two cerebral hemispheres. Each consists of: a body , anterior horn (frontal), posterior horn (occipital) and inferior horn (temporal). * The lateral ventricle communicates with the 3rd ventricle through the foramen of Monro (interventricular foramen). * The choroid plexus of the lateral ventricle : is a vascular process of pia mater projecting into the ventricular cavity . It receives its blood from 2 arteries: (i) the anterior choroidal artery (from internal carotid artery) (ii) the posterior choroidal artery (from posterior cerebral artery) The Third ventricle is a narrow vertical cleft between the two lateral ventricles, bounded on both sides by the 2 thalami. * It communicates with the 2 lateral ventricles through the foramina of Monro and with the fourth ventricle through the cerebral aquenduct. (aqueduct of Sylvius). The Fourth ventricle: is the cavity of the brain-stem, bounded ventrally by the pons and medulla, dorsally by the cerebellum, and laterally by the superior, middle & inferior cerebellar peduncles, the cuneate tubercles and the claves. * It is a continuation of the cerebral aqueduct to the central canal of the medulla. * It communicates with the 3rd ventricle through the aqueduct of Sylvius and with the subarachnoid space through the foramina of Luschka and Magendie (lateral and medial apertures). N.B.: The normal ventricular capacity ranges from 7 to 30 cc. CSF Formation: * CSF is mostly formed by the choroid plexuses of the ventricles particularly that of the lateral ventricles (95%). * Diffusion through ependymal and pial vessels is a probable source of the CSF. CSF Circulation: The CSF formed in the lateral ventricles —> Foramina of Monro —> 3rd ventricle —» aqueduct of Sylvius -> 4th ventricle —> foramina of Luschka and Magendie —> subarachnoid spaces, diffuses over the brain and spinal cord —> arachnoid villi —» venous sinuses —> Jugular veins. CSF Absorption : CSF is absorbed by the arachnoid villi to the dural venous sinuses and also by the pial veins. Function of CSF: (i) Protection of the brain and spinal cord by absorbing the shock. (ii) Convey nutritive materials to the CNS. (iii) Excretion of metabolites. (iv) Compensation for changes in intracranial volume. 84 N.B.: Queckenstedt's test: Compressing the jugular veins during lumbar puncture -> prompt rise in CSF pressure with prompt return to normal level on release of compression. * Complete or partial spinal block -> absence of pressure rise or a slow rise and a slow fall on compression of both jugular veins. * Thrombosis of the lateral sinus —> absence of pressure rise on compression of the ipsilateral jugular vein. N.B.: Froin's Syndrome : Xanthochromia ± cyto-albundnous dissociation + subarachnoid DiOCK. Superior sagittal sinus Arachnoid villi . The normal direction of cerebrospinal fluid flow (indicated by the arrows) as seen schematically from an anterior view. Dura mater Arachnoid mater Sutaarachnoid space Pia mater (adherent to the brain and spinal cord) Lateral ventricle •Third ventricle Cerebral aquaduct Fourth ventricle Foramen of Luschka Foramen of Luschka Foramen of Magendie flow (indicatec HYDROCEPHALUS Definition : increased volume of C S F within the skull. Varieties: 1. Compensatory hydrocephalus: increased volume of CSF with normal pressure. 2. Hypertensive hydrocephalus: both CSF volume and pressure are increased. It includes: (a) Obstructive hydrocephalus (non-communicating): due to obstructed CSF circulation. (a) Communicating hydrocephalus : due to increased formation and impaired absorption of CSF, or obstruction in the subarachnoid space e.g. by adhesions of meninges fol lowing meningitis. Causes: 1. Compensatory hydrocephalus: may occur in : (i) Cogenital cerebral hypoplasia. (ii) Acquired cerebral atrophy : e.g. M.S., G.P.I., senile or presenile dementias, in some epileptics and post-traumatic after severe head injury. 2. Hypertensive hydrocephalus: (a) Obstructive hydrocephalus: is due to obstruction of the CSF flow from the ventricles to the subarachnoid space e.g. i. Obstruction within the third ventricle e.g. by a neoplasm. 85 ii. Obstruction of the cerebral aqueduct (aqueduct of Sylvius) e.g. * Congenital aqueduct stenosis or atresia. * Gliosis or obstruction by tumours of the 3rd ventricle, midbrain or pineal body. iii. Obstruction of the fourth ventricle or its foramina by a posterior fossa tumour, or by adhesions following meningitis, (b) Communicating hydrocephalus : is due to: i. Increased CSF formation : e.g. in : * Meningism : lowering the osmotic tension of the blood. * Papiloma of the choroid plexus. * Meningitis causing congestion of the choroid plexus. * Vitamin A deficiency and hypervitaminosis A. ii. Obstruction of the cranial subarachnoid space : e.g. by a tumour,adhesions following meningitis, trauma or subarachnoid haemorrhage, or congenital, anomalies such as the Arnold-Chiary malformation or basilar impression. iii. Impaired absorption of the CSF due to : * Compression of venous sinuses by a brain tumour. * Raised intrathoracic pressure impeding venous return. * Superior sagittal sinus thrombosis secondary to lateral sinus thrombosis complicating otitis media or mastoiditis (Otitic hydrocephalus). * Meningitis causing obliteration of the arachnoid villi. Pathology: (i) Distension of the ventricles. (ii) Thinning of the cerebral hemispheres. (iii) Meningeal adhesions in post-meningitic cases. (iv) Thinning of the skull bones, separation of the sutures in young patients, erosion of the chinoid processes and excavation of the sella turcica (v) Atrophy of the optic nerves and olfactory tract is frequent. Clinical Picture: (A) Infantile Hydrocephalus: 1 . Enlarged head, with separated sutures, enlarged anterior fontanelle, and congested veins. 2 . A fluid thrill on percussion and an audible murmur on auscultation may be found. 3 * Forward and downward protrusion of eyes (rising sun sign) 4 . Absent or slight symptoms of increaed ICT. e.g. headache,vomiting & papilloedema. 5 . Convulsions, optic atrophy, and bilateral anosmia are common. 6 . Progressive deterioration of visual acuity up to blindness. 7 . Other cranial nerve palsies may occur. Squint and nystagmus may be present. 8. Weakness, spasticity, hyperreflexia, extensor plantar responses and incoordination are common in the lower limbs than in the U.Ls. 9 . Mental deficiency in severe cases. 10. Obesity in mild cases due to hypothalamo-hypophyseal compression. Wasting occurs in severe cases. 11. Cerebrospinal rhinorrhoea is rare. (B) Hydrocephalus after Infancy : Obstructive hydrocephalus: 1. Symptoms of increased ICT are marked e.g. headache, vomiting and papilloedema. 2. Head retraction, opisthotonos and impaired consciousness may occur. 3. Giddiness is common. 86 4. Mental deterioration, hallucinations, delusions and mood changes. 5. Convulsions are less frequent than in the infantile type. 6. Enlargement of the head is less marked, with slight separation of sutures in cases starting before the age of 18, leading to a "cracked-pot sound" on percussion. 7. Cranial nerve palsies e.g. 6th & 7th nerve palsies. 8. Slight exophthalmos. 9. Clumsiness and slight incoordination of limbs. 10. Hyperreflexia or hyporeflexia and extensor plantar responses with no sensory loss. 11. Obesity and genital atrophy may occur due to hypopituitarism. 12. CSF pressure is raised in communicating hydrocephalus, but normal or diminished in the obstructive type. 13. X-ray skull : Enlargement of the cranium, silver-beaten or finger-print appearance, separated sutures, deepening and expansion of the sella turcica with erosion of the clinoid processes may be present. 14. Ventriculography: shows marked dilatation of the ventricular system. Myodil ventriculography and isotope ventriculography may be helpful. Low pressure hydrocephalus (Hakim-Adams): 1. Age of onset: in middle and late life in most cases. 2. Confusion. 3.Ataxia. 4. Dementia. 5. Air ventriculography shows marked ventricular dilatation, but no subarahnoid air and the patient deteriorates much after this procedure. 6. Improved by a shunt operation. Differential Diagnosis: Infantile hydrocephalus must be distinguished from : 1. Rickets : bony bosses and other signs of rickets. 2. Megalencephaly : by air ventriculography. Benign Intracranial Hypertension (Toxic hydrocephalus): Raised CSF pressure in the absence of a space-occupying lesion and without ventricular enlargement. (a) Women, in the 4th decade, obese, with pregnancy or miscarriage, with a history of infection or head injury. (b) Otitic hydrocephalus is due to transverse or sagittal sinus thrombosis secondary to otitis media or mastoiditis. Clinically : Papilloedma, headache, vomiting, diplopia, visual failure and central scotomas. v Prognosis: * Untreated infantile hydrocephalus is fatal in most cases. * Survivors may show mental subnormality, blindness, or epilepsy. * In after infancy hydrocephalus, the prognosis depends on the cause. Treatment: (A) Infantile hydrocephalus: 1. Drainage of the CSF into the ureter and peritoneal cavity. 2. Drainage of the CSF into the jugular vein by a Spitz-Holter and Pudenz-Heyer valves. 3. Suboccipital decompression for Arnold-Chiary malformation. (B) Hydrocephalus after infancy : Treatment is that of the cause e.g. 1. Removal of a brain tumour. 2. Torkilsen's operation of ventriculocisternostomy for aqueduct stenosis. 3. Corticosteroids, diuretics, and repeated lumbar puncture for benign intracranial hypertension and otitic hydrocephalus. 4. Cranial decompression for visual failure. 87 CHAPTER 6 BRAIN TUMOURS CEREBRAL LOCALIZATION The two cerebral hemispheres are separated by the longitudinal cerebral fissure and connected together at the depth of this fissure by the corpus callosum. The surfaces of cerbral hemispheres present many fissures (sulci) and convolutions (gyri). Each cerebral hemisphere is divided into four main lobes: frontal, parietal, occipital and temporal lobes, as well as two important parts known as insula and rhinencephalon (limbic system or limbic lobe). * The lateral cerebral fissure (Sylvian fissure) separates the frontal from the temporal lobe. * The central sulcus (Fissure of Rolando) separates the frontal from the parietal lobe. * The Parieto-occipital fissure separates the parietal from the occipital lobe. * The precentral sulcus separates the precentral gyrus (area 4 ) from the rest of the fron tal lobe. * The superior & inferior frontal sulci divide the rest of the frontal lobe into superior, middle and inferior frontal gyri. * The post-central sulcus separates the post-central gyrus (areas 3, 1 & 2) from the rest of the parietal lobe. * The intraparietal sulcus divides the rest of the parietal lobe into the superior & inferior parietal lobules. The supramarginal gyrus is a part of the inferior parietal lobule that surrounds the upper end of the posterior ramus of the lateral fissure, while the angular gyrus is that part which surrounds the end of the superior temporal sulcus. The precuneus is the posterior part of the medial surface of the parietal lobe adjacent to the parieto-occipital fissure. * The lateral occipital sulcus divides the lateral surface of the occipital lobe into a superior and inferior gyrus. * The calcarine fissure divides the medial surface of the occipital lobe into the cuneus and the lingual gyrus. * The superior and middle temporal sulci divide the temporal lobe into superior, middle and inferior temporal gyri. * The inferior temporal sulcus separates the inferior temporal gyrus laterally from the fusiform (occipito-temporal) gyrus medially. * The transverse temporal gyrus (Heschl's gyrus) occupies the posterior part of the superior surface of the temporal lobe and is resposible for hearing. * The parahippocampal gyrus and uncus are responsible for olfaction. * The island ofReil (insula) occupies the depth of the Sylvian fissure. * Stimulation of the insula -> epigastric sensations & motor gastric response (belching or borborygmi). * The opercula of the insula are portions of the lips of the Sylvian fissure. They include the orbital, frontal, parietal and temporal opercula. * Rhinencephalon (Imbic system or visceral brain) includes the portions concerned with olfaction The center of each cerebral hemisphere is made of 3 types of myelinated nerves: 1. Commissural (transverse ) fibres: which connect the 2 hemispheres, e,g. the corpus callosum. 88 * The anterior commissure connects the 2 olfactory bulbs and the 2 piriform areas. * The hippocampal commissure connects the 2 hippocampi. 2. Projection fibres: include the corticopetal (afferent) and corticofugal (efferent) fibres. (a) The corticopetal fibres include: i. the optic radiation (the geniculocalcarine tract). ii. the auditory radiation. iii. thalamic radiation. (b) The corticofugal fibres include: i. The corticospinal and corticobulbar tracts. ii. The corticopontine tracts, iii. Corticothalamic fibres. iv . Corticorubral tract. 3. Association fibres: join the different parts of the same hemisphere. They include short and long association finers e.g. the uncinate fasciculus, cingulum, arcuate fasciculus, superior and inferior longitudinal fasciculi, occipitofrontal fasciculus and fornix. Brodmann's Classification of the Cortex: This was very helpful in functional localizations e.g. Area4 (The primary motor cortex): occupies the precentral gyrus and the anterior wall of the central sulcus. * It controls voluntary movements of the opposite half of the body via the corticospinal and corticobulbar tracts originating from the Betz - cells. * The body is represented in area 4 inverted upside down. * Stimulation (irritative lesions) of area 4 —» contralateral jacksonian seizure. * Destruction of area 4 —» contralateral flaccid hemiparesis or hemiplegia (more marked distally). Area 6 (The premotor area) is located anterior to area 4 and constitutes a part of the extrapyramidal system. * Stimulation of area 6 -> stereotyped movements with turning of the head and torsion of the body (if area 4 is ablated beforehand). * Destruction of area 6 —» forced grasping in monkeys. * Combined destruction of area 4 & 6 —»contralateral spastic hemiplegia. Area 8 (frontal eye movement and pupillary change area) is located in the posterior part of the middle frontal gyrus. * Stimulation (irritative lesion) of area 8 -> conjugate deviation of the head and eyes to the opposite side. * Destruction of area 8 —> paralysis of the conjugate gaze to the opposite side with deviation of the eyes to the side of the lesion. Areas 9 ,10 ,11 and 12 (frontal association areas): are responsible for mentality, intelle ctual functions and emotions. Prefrontal lobotomy (as a treatment of intractable pain, anxiety, depression, ...etc)-> reduced intellectual functions with decreased vocabulary functions and emotional changes. Areas 3 , 1 & 2 (The primary sensory cortex or somesthetic area): occupy the postcentral gyrus and receive general sensations from the opposite side of the body through the thalamic radiations. * Irritative lesions of areas3 , 1 and 2 -» paresthesias of numbness, tingling and electric shock sensations on the contralateral side of the body (sensory jacksonian seizure) * Destruction of areas 3 , 1 and 2-> contralateral hemihypoesthesia of the cortical type (loss of tactile localization and two point discrimination). N.B. The cortical taste area lies in the area for facial sensations. Areas 5 & 7 (Sensory association areas): are responsible for stereognosis. Area 17 ( The primary visual cortex): is located in the occipital lobe. * Irritative lesions of area 17 —»Unformed visual hallucinations e.g. flashes of light. * Destructive lesions —»contralateral homonymous hemianopia with macular sparing. Areas 18 & 19 (Secondary & tertiary visual association areas): area 18 is responsible for 89 visual recognition, area 19 is responsible for visual recall and revisualization of objects. * Destructive lesions of areas 18 & 19 on the dominant hemisphere produce visual agnosia. N.B : (1) Parietal or temporal lobe lesions may cause visual field defects by interruption of the optic pathways. (2) Temporal lobe lesions may cause visual hallucinations of formed objects or subjects. Area 52 (The primary auditory area) : is located in the Heschl's gyrus (the transverse temporal gyrus). It receives the auditory radiation from the medial geniculate body which carries auditory impulses from the cochlea of the ear. * Irritative lesions of area 52 -> auditory hallucinations e.g. buzzing and roaring. * Destructive lesions of area 52 -> mild deafness. Areas 41 & 42 (The cortical secondary & tertiary auditory areas or associative auditory cortex) surround area 52. * Destructive lesions of area 41 & 42 in the dominant hemisphere ' -> auditory agnosia. Areas 20 , 21, 22 & 38 , (Temporal association areas) Area 37 : is the language formulation area. * Destructive lesions of area 37 —> nominal aphasia. The olfactory area : lies in the uncus and parahippocampal gyrus of the temporal lobe. * Irritative lesions -»olfactory hallucinations (uncinatefits). * Destructive lesions —> anosmia. Area 44 (Broca's area or Motor speech centre ) : is located in the posterior part of the inferior frontal gyrus of the dominant hemisphere (left hemisphere in rig ht - handed people). * Destructive lesions of area 44 —> Motor aphasia. Area 39 (angular gyrus): is the higher association area of symbol langauge. * Destructive lesions of area 39 in the left hemisphere —> Sensory aphasia e.g. word blindness. Area 40 is the supramarginal gyrus. Brodmann's areas on the lateral surface of the cerebral hemisphere 8 (FB): Promoter pyramidal circuit) Area 4 (FA): Principal Area motor area area (part of extra- Areas 18-19 (OB-OA): Visual association areas Area 41 (TC): Primary auditory cortex The lateral aspect of the cerebrum. The cortical areas are shown according to Brodmann (numbers) and von Econoi (letters), with functional localizations. 90 Optic nerve Anterior Op*ic chiasm perforated substance Optic .tract Infundibulum Mammillary body Oculomotor Trochlear nerve nerve Crus Rons cerebn Abducens nerve Trigemmal nerve Glossopharyngea! nerve Facial nerve Hypoglossal nerve Vestibulocochlear Pyramidal decussation nerve Vagus nerve Spinal accessory nerve Ventral root C| Drawing of the anterior aspect of the medulla, pons and midbrain HI Ventricle -Stria medullaris Habenula Pulvinar Brochium Superior colliculus Lateral geniculate body Inferior colliculus Cerebellor peduncles Colliculu Superior Middle s Superior Inferior Inferior Trochlear n Vestibular area Medial eminence Lateral aperture Stria medullaris (EZ vent) Facial colliculus Tuberculu m Cuneatus Post intermediate sulcus Gracilis Fasciculu s Cuneatus Gracilis Post, median sulcus Drawing of the posterior aspect of the brain stem with the cerebellum removed BRAIN TUMOURS Definition : Space-occupying lesions within the skull, whether neoplastic or chronic inflammatory in origin. Neoplasms Affecting the Central Nervous System PATHOLOGLCAL VARIETIES : 1 - Gliomas : 40 - 50 % of all intracranial neoplasms. They include: 1. Medulloblastoma: (a) Common in children, rare in adults. (b) Arises in the cerebellum (in the roof of the 4 th ventricle). (c) Rapidly growing malignant tumour. (d) Subarachnoid metastases. (e) Average survival period is 6 to 12 months. (/*) Radiotherapy retards its growth. 2. Glioblastoma (Spongioblastoma) Multiforme: (a) Middle life. (b) Arises in the cerebral hemispheres. (c)Highly vascular with haemorrhage and necrosis. (d) Extremely malignant (e)Average survival period is 12 months after operation. 3. Astrocytoma: (0)Any age. (b) Arises in the cerebral, or in the cerebellar hemispheres. (d) Cystic transformation is frequent. (c) Slowly growing and relatively benign. 4. Oligodendroglioma: Rare (6)Arises in the cerebral hemispheres. (a)Young adults. (e) Calcification may occur. (c)Slowly growing and relatively benign. (d) Malignant anaplasia may occur. 5. Ependymoma : Rare (a) Arises in the roof of the 4 th ventricle, walls of other ventricles, or from the central canal of the spinal cord. (6)Rosette formation. 6. Ganglioglioma, Ganglioneuromas, and Neuroblastomas are rare. 91 II - Meningiomas : 10% (a) Attached to the dura, but arising from the arachnoid cells of the arachnoid villi. (b) The cells are arranged in columns or whorls. (c) Meningioma may contain small calcified concretions (psammoma bodies). (d) Meningioma is usually single, large and lobulated tumour but rarely it may form a flat plaque. (e) It invades the overlying bone in 20 % of cases, with bone absorption and new bone formation (hyperostosis). (f) It does not invade the brain bur compresses it. (g)Meningiomas are usually found along the venous sinuses, e.g. parasagittal meningiomas, meningiomas of the convexities, sphenoidal ridge meningioma, olfactory groove meningiomas, suprasellar meningiomas, tentorial meningioma and intraventricular meningiomas. (h) Multiple meningiomas are occasionally seen with multiple neurofibromatosis. (i) Meningiomas are common is females than in males and are rare before middle life. (/) X - ray base of the skull may show enlargement of the formen spinosum, which transmits the middle meningeal artery. HI - Acoustic Neuroma : 5 - 10 % (a) Usually unilateral, rarely bilateral as a part of multiple neurofibromatosis (von Recklinghausens disase). (b) The commonest site of neuroma is the 8 th nerve, but may occur upon the optic, trigeminal, the dorsal roots of spinal nerves and upon peripheral nerves. (c) It consists of elongated cells like spindle fibroblasts, with palisading and parallelism of nuclei. IV - Tumours of the Blood Vessels: 1. Angiomatous Malformations : are congential abnormalities of vascular development. Two types: (a) Telangiectases or capillary angiomas : consist of dilated capillaries. (b) Arteriovenous Malformations: consist of dilated tortuous cortical vessels usually in the field of the middle cerebral artery. Clinically: increased vascularity of the scalp, pulsating arteries, hypertrophy of carotids, bruits over one or both carotids and over the angioma. 2. Cavernous Haemangiomas : are congenital abnormalities, usually supra - tentorial, forming a lobulated mass of blood - filled spaces. 3. Haemangioblastomas: (a) They are vascular channels and spaces with a tendency to form cysts containing xanthochromic fluid. (b) The tumour may appear as a small nodule in the wall of a large cyst. (c) Usually subtentorial (cerebellar ) and single, rarely multiple tumours occur in the cerebellum with or without a tumour in the medulla or spinal cord. (d) A cerebellar haemangioblastoma may be associated with a haemangioblastoma of the retina (Von Hippel's disease). (e) It may be associated with a haemangioblastoma of the spinal cord, polycystic pancreas and kidneys , hypernephromas of the kidneys or the suprarenal glands (Lindaus disease). (f) Polycythaemia. (g) Positive family history in 20 % of cases. 4. Sturge - Weber Syndrome: (a) A capillary - venous malformation, commonly in the parieto - occipital region, with a 11 wavy " pattern of subcortical calcification that outlines the gyri. (b) A " port - wine" stain on the affected side of the face. (c) Buphthalmos (ox eye ). (d) A contralateral hemiparesis and epilepsy. 92 V - Craniopharyngiomas : (tumours of the craniopharyngeal or Rathke's pouch, adamantinomas, or hypophysial epidermoids) (a) Usually suprasellar, occasionally intrasellar. (b) Cystic degeneration, calcification and bony changes are frequent. VI- Pituitary Tumours : 5% 1. Chromophobe adenoma: is the commonest and produces " hypopitidtarism"'. 2. Acidophil adenoma: produces " hyperpituitarism" i.e. acromegaly in adults and gigantism if occurs before puberty. 3. Basophil adenoma : is of microscopic size and produces Gushing's syndrome. 4Adenocarcinoma of the pituitary is rare. 5. Intrasellar metastases are rare e.g. from cancer breast. VII - Cholesteatoma (Cerebrospinal epidermoid): (a) Rare; affects adults, males more than females. (b) Sites; in the subarachnoid cisterns at the base of the brain e.g. in the cerebellopontine angle, ventral aspect of the cerebellum, 4 th ventricle, or in the temporal bone. VIII- Tumours of the Pineal Gland (Pinealomas): are rare. They were considered atypical teratomas. IX - Colloid Cysts of the Third Ventricle : arise from the choroid plexus and cause hydrocephalus. X - Papilloma of the choroid plexus : is commoner in the 4 th ventricle than in the lateral or 3 rd ventricles. It may cause recurrent subarachnoid haemorrhage or communicating hydrocephalus. XI - Glomus Jugulare Tumours: may invade the middle ear or the posterior fossa. Clinically : (a) Unilateral deafness . (b) Multiple cranial nerve palsies, (c) Radiological evidence of erosion of the base of the skull. XII - Metastatic Tumours : 15 - 20 % (a) Carcinomas of the lung, breast, stomach, prostate, thyroid and kidney are the common sources of brain metastases. (b) Usually met with in middle and late life. (c) Secondary cerebral carcinomas are commoner than secondary sarcomas. (d) Usually muliple, rounded, well defined, pinkish and rapidly growing. (e) 4 th ventricular metastases present with morning headache, morning vomiting and postural vertigo. (f) Carcinomatosis of the meninges result in : * multiple cranial nerve palsies. * neck stiffness. * headache. * confusion and * rarely subdural haematoma. (g) Secondary melanotic sarcoma: may cause subarachnoid haemorrhage. XIII - Tumours of Infective Origin: 1. Tuberculomas : commonly subtentorial (cerebellar) than supratentorial. A tuberculoma consists of a yelow caseous centre surrounded by a pinkish-grey outer zone . Calcification is frequent. Commoner in young age. Remissions and relapses are common. A primary T.B. lesion elsewhere favours the diagnosis. 2. Gumma of the brain: is very rare and may start as a patch of gummatous meningitis. Positive W.R. 3. Parasitic Cysts: may act as a space-occupying lesion e.g. hydatid cysts and cysticercus cellulosae. Eosinophilia, and mononuclear pleocytosis in the CSF may be present. 4. Brain Abscess: secondary to otitis media, pyaemia, or trauma. 93 CLINICAL PICTURE OF BRAIN TUMOURS (A) GENERAL SYMPTOMS OF INCREASED ICT: The classical triad of symptoms includes: headache, papilloedema, and vomiting. This is present in only 60% of cases. 1. Headache: * Paroxysmal at first, later continuous. * Throbbing or bursting in character. * More during the night and in the early morning. * Increased by exertion, excitement, coughing, sneezing, vomiting, stooping and straining at defaecation. * It may be affected by the posture of the head. * It is of a little localizing value, but usually subtentorial tumours give suboccipital headache radiating down the back of the neck and may be increased by flexion of the neck. * Head ratraction may be present. 2. Papilloedema: * Constant and severe in cerebellar, 4th ventricular, and temporal lobe tumours, absent in 50% of cases of pontine and subcortical tumours, late in prefrontal tumours. * Enlargement of the blind spot with concentric constriction of the field of vision. * Progressive deterioration of the visual acuity. * Post- papilloedemic optic atrophy and blindness may occur. * Ipsilateral primary optic atrophy and contralateral papilloedema may occur in olfactory groove meningioma (Foster Kennedy syndrome) 3. Vomiting: * It occurs at night and in the early morning . * It accompanies headache and may partially relieve it. * It is not preceded by nausea except in children and not related to meals . * Sometimes projectile in character. 4. Convulsions: * Major fits occur in about 30 % of cases. * Most common in cases of astrocytoma (68%), meningioma (60%) and glioblastoma (51%) 5.Vertigo : A feeling of unsteadiness with a tendency to fall on stooping may occur. 6. Pulse : Acute rise of ICT causes bradycardia. Gradual increase in ICT causes tachycardia. 7. B.P.: A rapid rise of ICT causes a rise in B.P. Chronic rise of ICT produces subnormal B.P. 8. Respiratory Rate : Arapid rise of ICT with loss of consciousness produces slow and deep respiration , or Cheyne - Stokes respiration A gradual rise of ICT unaffects the respiratory rate. 9. Hypopituitarism : may occur due to downward pressure of the floor of the dilated 3rd ventricle. Clinically : adiposity, genital atrophy, loss of body hair, hypoadrenalism and hypothyroidism. 10. Somnolence: is met with in severe hydrocephalus due to hypothalamic affection. 11. Glycosuria: may occur. 12. Mental Symptoms: * Acute rise of ICT produces coma. * Subacute rise of ICT produces mental confusion with disorientation in time and space. * Chronic rise of ICT may cause progressive dementia, or confusion, disorientation and hallucinations. * Rarely, excitement or depression may occur. * Impaired memory with inability to concentrate and irritability are met with in mild cases. 94 * Mental symptoms are common in frontal lobe or corpus callosal tumours, or a result of increased ICT e.g. in cerebellar tumours. 13. False Localizing Signs: (a) Cranial nerve palsies : e.g. 6th nerve palsy and 3rd nerve palsy due to stretching of the nerves and tentorial herniation. (b) Bilateral extensor plantar responses. (c) Bilateral grasp reflexes due to pressure by the dilated ventricles in hydrocephalus. (d) Hypopituitarism due to downward pressure of the floor of the 3rd ventricle. (e) Extensor plantar response on the same side as a hemispherical tumour due to compression of the opposite cerebral peduncle against the tentorium. (f) Cerebellar symptoms in frontal lobe tumours. (g) Midbrain symptoms e.g. fixed dilated pupils, resulting from a vermal cerebellar tumour. (B) FOCAL SYMPTOMS: 1. Frontal Lobe Tumours : 1. Prefrontal Tumours : (i.e. tumours anterior to the precentral gyrus). (i) Headache is early, but papilloedema and vomiting are late or absent. (ii) Mental symptoms may precede signs of increased ICT. They include : progressive dementia with intellectual deterioration, stupidity, carelessness, urinary and faecal incontinence, sometimes jocular, irritable, or depressed, (iii) Generalized convulsions in about 50 % of cases with aura associated with speech (if the tumour is near the base) or turning of the head and eyes to the opposite side with toni-clonic movements of the contralateral limbs (in tumours near the superior aspect of the lobe). (iv) Catalonia (immobility in one attitude), or waxy flexibility, (v) Motor (expressive) aphasia : due to involvement of the Broca's area, (vi) Grasp reflex in the opposite hand and / or foot, (vii) Tonic perseveration (failure of relaxation after voluntary muscular contraction) is a rare sign of frontal lobe lesions . (viii) Contralateral hemiparesis most marked in the face and tongue, due to compression of the pyramidal fibres, (ix) Ipsilateral anosmia due to pressure upon the olfactory nerve, ipsilateral primary optic atrophy due to compression of the optic nerve, and contralateral papilloedema due to rise of ICT are met with in olfactory groove meningioma and known as Foster Kennedy syndrome. (x) Cerebellar symptoms may occur as a false localizing sign . 2. Precentral Tumours: (i.e. tumours of the motor cortex) (a) Pyramidal excitation: produces contralateral focal convulsions: i. Typical Jacksonianfits : clonic movements of a focal onset e.g. in the thumb, march course according to the order of representation of the body in the motor cortex, loss of consciousness if the opposite side is involved. They are often followed by temporary hepiparesis (Todd's paralysis). ii. Partial Jacksonian attacks: limited to a small part of one side of the body and may be continuous (epilepsia partialis continud). iii. Serial Jacksonian epilepsy: frequent attacks up to several hundreds per day. iv. Jacksonian status epilepticus with no recovery of consciousness between successive attacks. (b) Pyramidal destruction : produces contralateral monoplegia. Parasagittal meningioma compressing the paracental lobules produces paraparesis, retention of urine and impairment of position sense in the toes if the sensory area is affected. 95 Signs Associated with Localized Lesions Location of Lesion Prefrontal area Frontal eye fields Precentral gyrus Superficial parietal lobe Angular gyrus Broca's area Superior temporal gyrus Midbrain Associated Signs Loss of judgment, failure of memory, inappropriate behavior, apathy, poor attention span, easily distractible, release phenomena Failure to sustain gaze to opposite side, saccadic eye movements, impersistence, seizures with forced deviation of the eyes to the opposite side Partial motor seizures, jacksonian seizures, generalized seizures, hemiparesis Partial sensory seizures, loss of cortical sensation including two-point discrimination, tactile localization, stereognosis and graphism Agraphia, acalculia, finger agnosia, allochiria (right-left confusion) (Gerstmann's syndrome) Motor dysphasia Receptive dysphasia Early hydrocephalus; loss of upward gaze; pupillary abnormalities; third nerve involvement-ptosis, external strabismus, diplopia; ipsilateral cerebellar signs; contralateral hemiparesis; parkinsonism; akinetic mutism Cerebellar Ipsilateral cerebellar ataxia with hypotonia, dysmetria, intention tremor, nyshemisphere tagmus to side of lesion Pons Sixth nerve involvement-diplopia, internal strabismus; seventh nerve involvement- ipsilateral facial paralysis; contralateral hemiparesis; contralateral hemisensory loss; ipsilateral cerebellar ataxia; locked-in syndrome Medial surface of Apraxia of gait, urinary incontinence frontal lobe Corpus callosum Left-hand apraxia and agraphia, generalized tonic-clonic seizures Thalamus Contralateral "thalamic pain," contralateral hemisensory loss Temporal lobe Partial complex seizures, contralateral homonymous upper quadrant-anopsia Paracentral lobule Progressive spastic paraparesis, urgency of micturition, incontinence Deep parietal lobe Autotopagnosia, anosognosia, contralateral homonymous lower quadrantanopsia Third ventricle Paroxysmal headache, hydrocephalus Fourth ventricle Hydrocephalus, progressive cerebellar ataxia, progressive spastic hemiparesis or quadriparesis Cerebellopontine Hearing loss, tinnitus, cerebellar ataxia, facial pain, facial weakness, dysphaangle gia, dysarthria Olfactory groove Ipsilateral anosmia, ipsilateral optic atrophy, contralateral papilledema (Foster-Kennedy syndrome) Optic chiasm Incongruous bitemporal field defects, bitemporal hemianopsia, optic atrophy Orbital surface frontal Partial complex seizures, paroxysmal atrial tachycardia lobe Optic nerve Visual failure of one eye, optic atrophy Uncus Partial complex seizures with olfactory hallucinations (uncinate fits) Basal ganglia Contralateral choreoathetosis, contralateral dystonia Internal capsule Contralateral hemiplegia, hemisensory loss, and homonymous hemianopsia Pineal gland Loss of upward gaze (Parinaud's syndrome), early hydrocephalus, lid retraction, pupillary abnormalities Occipital lobe Partial seizures with elementary visual phenomena, homonymous hemianopsia with macular sparing Hypothalamus/ Precocious puberty (children), impotence, amenorrhea, galactorrhea, hypopituitary thyroidism, hypopituitarism, diabetes insipidus, cachexia, diencephalic autonomic seizures 96 II - Temporal Lobe Tumours : 1. Tumours of the uncus (the cortical centre for taste and smell, licking, mastication and swallowing movements) may cause uncinatefits: (a) Aura of gustatory and olfactory hallucinations, usually unpleasant. (b) Involuntary licking, smacking the lips, or tasting movements. (c) Dreamy state with a lapse of consciousness, but the patient does not fall. (d) Amnesia for the attack afterwards, or deja vu phenomenon, or illusions e.g. micropsia, macropsia, derealization, depersonalization (jamais vu), or fear and depression. 2. Destruction of the uncus produces partial impairment of taste and smell on the ipsilateral side. 3. Generalized convulsions may occur. 4. Bilateral partial impairment of hearing in tumours of the posterior part of the temporal lobe (cortical hearing centre). 5. Tinnitus or auditory hallucinations. 6. Aphasia in left-sided temporal lobe tumours. Word deafness (inability to understand spoken words) may occur. Jargon aphasia (voluble speech of meaningless phrases or abnormal words) in severe cases. Apraxia may occur. 7. Visual field defects in about 50% of cases. A crossed upper quadrantic hemianopia is characteristic, due to compression of the lower fibres of the optic radiation. 8. Neighbour hood symptoms: e.g. (a) Weakness of conjugate deviation of the eyes to the opposite side. (b) Pyramidal signs on the opposite side e.g. facial weakness. (c) Partial ptosis and myosis due to affection of the ocular sympathetic. (d) 3rd nerve palsy may occur. (e) Diminished corneal reflex on the affected side (5th nerve compression). HI - Parietal Lobe Tumours : 1. An irritative lesion of the postcentral gyrus (the principal sensory area) causes sensory Jacksonianflts (paraesthesiae of tingling or electric shocks and rarely of pain) on the opposite side of the body. Sensory Jackspnian fits may be followed by motor Jacksonian fits if the precentral gyrus is involved. 2. A destructive lesion of the postcentral gyrus leads to sensory loss of the cortical type (loss of postural sensibility, tactile discrimination, and astereognosis). 3. Hypotonia and wasting of the affected parts and both static and kinetic ataxia (sensory ataxia in the finger-nose test) and pseudoathetosis may occur. 4. Thalamic over-reaction may occur in deeply seated parietal tumours. 5. Crossed homonymous lower quadrantic hemianopia due to compression of the upper fibres of the optic radiation. 6. Alexia (inability to read) and agraphia (inability to write), with or without finger agnosia and acalculia (inability to calculate) in lesions of the left angular gyrus. 7. Autotopagnosia (unawareness of the opposite half of the body) with neglect of objects in the opposite half of extrapersonal space, in lesions of the right angular gyrus. 8. Ideational apraxia in lesions of the left supramarginal gyrus. IV - Occipital Lobe Tumours : 1. Symptoms and signs of increased ICT are early e.g. headache 2. Convulsions in about 50% of cases with visual aura of flashes of light. 3.Visual field defects e.g. a crossed horaonymous hemianopia or a crossed homonymous quadrantic defect, or a crescentic loss in the periphery of the opposite half fields. 4. Visual object agnosia and agnosia for colours in lesions of the left lateral occipital region. 5. Neighbour hood symptoms e.g. 97 (a) Alexia and agraphia due to compression of the left angular gyrus. (b) Auditory hallucinations with word-deafness due to compression of the posterior part of the temporal lobe. (c) Impairment of taste and smell due to compression of the uncus. (d) Cortical sensory impairment on the opposite side. (e) Slight motor weakness on the opposite side. (0 Nystagmus, hypotonia and inco-ordination due to cerebellar compression. V - Tumours of the Corpus Callosum : 1. Mental symptoms are frequent e.g. apathy, drowsiness and memory defect with progressive dementia. 2. Convulsions (major or focal fits) are common. 3. Double hemiplegia due to damage of both pyramidal tracts. 4. Grasp reflex unilateral or bilateral, due to extension of the tumour into the frontal lobes. 5. Apraxia may occur e.g. left-sided apraxia due to interruption of fibres connecting the left supramarginal gyrus with the right pyramidal tract. 6. Choreiform movements and tremors may occur due to compression of the corpus striatum. 7. Signs of increased ICT are late. 8. CSF protein content is raised. VI - Tumours of the Basal Ganglia : 1. Progressive spastic hemiplegia on the opposite side. 2. Sensory loss and sensory ataxia on the opposite side. 3. Homonymous hemianopia (affection of the optic radiation) 4. Somnolence. S.Weakness of conjugate deviation upwards and inequality of puplis due to pressure upon the upper part of the midbrain. 6. Signs of increased ICT develop rapidly when the 3rd ventricle is invaded. Vn - Tumours of the Third Ventricle : may be: (a) Intraventricular e.g. a colloid cyst, or (b) Extraventricular e.g. tumours of the corpus callosum (above), of the basal ganglia (laterally), or of the interpeduncular space (below). Clinically : 1. Hydrocephalus : acute, subacute, chronic, or intermittent. 2. Paroxysmal headache which may be positional. 3. Papilloedema. 4. Progresive dementia, or coma may occur. 5. Pyramidal signs unilateral or bilateral (compression of internal capsule). 6. Amnesia. 7. Somnolence, polyuria, hyperglycemia, glycosuria, obesity, sexual regression and irregular pyrexia may occur due to downward pressure upon the tuber cinereum and pituitary gland. VQI - Tumours of the Midbrain : 1. Internal hydrocephalus is early due to obstruction of the cerebral aqueduct causing severe headache, vomiting and papilloedema. 2. Weakness of conjugate ocular deviation upwards with or without retraction of the upper eye lid in upper midbrain tumours. 3. Weakness of conjugate ocular deviation downwards with or without ptosis and weakness of convergence in lower midbrain tumours. 98 4. Bilateral paralysis of the lateral conjugate gaze may occur in tumours just above the pons. 5. Dilated unequal pupils with reflex iridoplegia 6. Nuclear ophthalmoplegia may occur. 7. Bilateral pyramidal signs with weakness, spasticity and hyperreflexia. Decerebrate rigidity may occur. 8. Tonic fits with opisthotonos, extension of the 4 limbs and loss of consciousness may occur. 9. Tremor, nystagmus and ataxia may occur due to damage of the cerebellar connections. 10. Choreiform movements may occur. 11. Sensory loss due to affection of the long ascending sensory tracts. 12. Deafness, unilateral or bilateral due to compression of the lateral lemniscus. IX - Pineal Body Tumours : 1. Signs of a midbrain lesion with early hydrocephalus as described above. 2. Macrogenitosomia praecox (of unknown cause). 3. Hypopituitarism and obesity may occur. X - Tumours in the Region of the Optic Chiasma include : 1. Pituitary tumours. 3. Suprasellar meningiomas, & Pituitary Tumours: 2. Craniopharyngioma. 4. Gliomas of the optic chiasma. (A) Endocrine Disturbances: 1. Chromophil (Acidophil) Adenoma : causes hyperpituitarism with over production of growth hormone leading to gigantism (if it arises before puberty) or acromegaly (if arises in adult life), hyperglycaemia and glycosuria, thyrotoxicosis, hypertrichosis, impotence in males and amenorrhoea in females and enlarged breasts with lactation (excessive prolactin) 2. Chromophobe Adenoma : causes hypopituitarism leading to oligomenorrhoea or amenorrhoea in females and impotence in males, soft skin with loss of hair e.g. axillary and pubic hair, obesity, low metabolic rate, increased sugar tolerance, hypothyroidism, hypoadrenalism, and hypogonadism. 3. Basophil Adenoma : may produce Cushing's syndrome with painful, plethoric adiposity, cutaneous striae and purpuric patches, hirsutism, amenorrhoea, hyperglycaemia, hypertension, polycythaemia & osteoporosis. (B) Pressure Symptoms: 1. They may be absent in basophil and acidophil adenomas. 2. Headache, at first due to expansion of the sella (bursting and bitemporal) and later due to increased ICT. Vomiting is absent or late. 3. Visual field defects : (a) Bitemporal hemianopia usually asymmetrical, starting in the upper temporal quadrant on one side. (b) It may begin as a scotoma in the temporal half of the field. (c) Complete blindness of one eye with temporal hemianopia in the other. (d) Homonymous hemianopia occurs if one optic tract is compressed. 4. Primary optic atrophy, usually more marked on one side, but papilloedema is rare. 5. Ocular palsies due to compression of the 3rd or 6th cranial nerves and trigeminal pain, sometimes with analgesia referred to the ophthalmic division of the 5th nerve. 6. Pyramidal signs, unilateral or bilateral due to compression of the cerebral peduncles or of one hemisphere. 7. Uncinateflts due to compression of the uncus. 8. Mental changes due to compression of the frontal lobe. 99 (C) Radiographic Findings: Expansion of the sella and thinning of its walls. Craniopharyngioma : 1. Endocrine Disturbances : due to compression of the pituitary and / or the tuber cinereum resulting in adiposity or emaciation, polyuria, dwarfism, sexual infantilism, or premature physical senility, or diabetes insipidus later in life. 2. Pressure Symptoms : (i) Symptoms of increased ICT : Enlarged skull with separation of the sutures in children, headache, vomiting and papilloedema. (ii) Field defects due to compression of the optic nerves, chiasma, or tracts, (iii) Compression of frontal lobes, temporal lobes and cerebral peduncles may occur. 3. Radiographic Findings : e.g. general signs of increased ICT, erosion of the clinoid processes, flattening of the sella and calcification (suprasellar or intrasellar). Suprasellar Meningioma: 1. It occurs in adult life. 2. Headache is slight. 3. No endocrine symptoms. 4. Visual field defects e.g. hemianopia, or a central, or temporal paracentral scotoma. 5. Primary optic atrophy . 6. Uncinate fits due pressure upon the uncus. 7. Generalized convulsions. 8. Hemiparesis. 9. X-ray skull may show erosion of the optic canal or clinoid processes, with flattening of the sella and sometimes calcification. Glioma of the Optic Chiasma : is rare. 1. It occurs in childhood. 2. Multiple neurofibromatosis may co-exist with it. 3. Primary optic atrophy with visual deterioration. 4. Visual field defects are bizarre. 5. Exophthalmos may occur. 6. No endocrine disturbances. 7. X-ray may show enlargement of the optic foramen and rarely enlargement of the sella turcica forwards. XI.- Cerebellar Tumours: (A)Midline Cerebellar Tumours : e.g. Medulloblastoma. 1. 2. 3. 4. 5. It affects children. Early symptoms of increased ICT including headache, vomiting and papilloedema. Enlarged skull with separated sutures. Trunkal ataxia with little or no ataxia of the limbs. Giddiness and unsteadiness with a broad-based gait and tendency to fall backwards or forwards. 6. Muscular hypotonia. 7. No nystagmus. 8. Midbrain compression with tonic fits (extension of the limbs, opisthotonos, and loss of consciousness), and the pupils may be dilated and slightly reacting . 9. Sixth and 7th nerve palsies may occur. 10. Weakness of the limbs, extensor plantar responses and sluggish reflexes (due to increased ICT) may occur. (B) Tumours of the Cerebellar Hemispheres : e.g. Astrocytoma and cystic haemangioblastoma. 1. Early signs of increased ICT with suboccipital headache. 2. Nystagmus most marked on looking to the side of the lesion . 3. Ataxia of the limbs on the side of the lesion with clumsiness of the hand, positive finger-nose and heel-knee tests and adiadochokinesis. 100