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THE EAR Dr. Basil M.N. Saeed Assistant professor ENT Department College of Medicine Mosul University Embryology Auricle : a series of six tubercles which form around the margins of the first visceral cleft about 6 weeks of gestation. External Auditory Canal : Ectoderm of the first visceral cleft. Tympanic Membrane 1. An outer epithelial layer; the ectoderm of the first visceral cleft. 2. A middle fibrous layer; the mesoderm between the first visceral cleft and the tubotympanic recess. 3. An inner mucosal layer; the entoderm of the tubotympanic recess. Eustachian Tube and Tympanic Cavity The dorsal recess of the first and second entodermal pouches fuse to form the tubotympanic recess. The recess expands around the ossicles forming the Eustachian tube and tympanic cavity. ANATOMY THE EXTERNAL EAR It consists of the PINNA or AURICLE and the EXTERNAL AUDITORY MEATUS. THE AURICLE : Plate of yellow elastic cartilage, except for the lobule. The skin of the lateral surface is closely adherent to the perichondrium. The auricle is attached to the side of the head by ligaments and rudimentary auricular muscles. Parts of the auricle include: Helix, Antihelix, Tragus, Antitragus, Concha and Lobule THE EXTERNAL ACOUSTIC MEATUS It measures about 2.5 cm. It is composed of two parts: an outer or lateral third, which has a cartilaginous skeleton directed medially upwards and backwards; and an inner two thirds which has a bony skeleton and is directed medially, slightly downwards and forwards. The meatus can be partly straightened in adults by pulling the auricle upwards, outwards and backwards. The external canal ends medially at the tympanic membrane THE EXTERNAL ACOUSTIC MEATUS The skin of the cartilaginous canal is closely adherent to the underlying tissues and contains sebaceous glands, ceruminous glands and hair follicles. These structures are absent in the bony canal. The blood supply: superficial temporal and posterior auricular branches of the external carotid artery. Nerve supply: fifth, ninth, tenth cranial nerves, greater auricular and lesser occipital nerves of the cervical plexus. THE MIDDLE EAR It is an air filled cavity within the petrous part of the temporal bone. The temporal bone has four parts: tympanic, squamous, petrous and mastoid. It is called the tympanic cavity and lies between the tympanic membrane TM laterally and the cochlea (inner ear)medially. It is a six-sided box with its vertical length greater than its breadth. THE MIDDLE EAR The roof of the middle ear is formed by a thin plate of bone called the tegmen tympani which separates the the middle ear cavity and the mastoid antrum from the middle cranial fossa. The floor is formed by a thin plate of bone which separates the middle ear cavity from the bulb of the internal jugular vein. The anterior wall In its lower portion is formed by a thin plate of bone separating the cavity from the internal carotid artery. The upper part has two openings, the lower one being the auditory( eustachiuan) tube and above it lies the canal for the tensor tympani muscle. The posterior wall The aditus which is an opening leading from the middle ear to the mastoid antrum, and to mastoid air cells . The pyramid, which is a conical bony projection bellow the aditus. The stapedius tendon comes out of the pyramid and is inserted to the stapes. The fossa incudis lies just above the pyramid and it receives the attachment of the short process of the incus. The facial nerve bends downwards at the level of the fossa incudis and lies close to the posterior wall( the mastoid segment of the facial nerve). The lateral wall It is formed by the tympanic membrane which separates the external canal from the middle ear. The membrane has an outer layer of squamous epithelium continuous with the skin of the meatus, a middle fibrous tissue layer and an inner layer of mucus membrane continuous with the lining of the middle ear cavity. It is about 0.9 cm in diameter. The fibrous middle layer is found in the lower 2 thirds of the tympanic membrane and is called PARS TENSA, and deficient in the upper third and is called PARS FLACCIDA which is bounded by the anterior and posterior malleolar folds. The medial wall It is the lateral wall of the inner ear. Has the followings The oval window which is closed by the footplate of the stapes. The round window, lies below the oval window and is closed by the secondary TM. The promontory which represents the basal turn of the cochlea is situated between and in front of the 2 windows. The tympanic part of the facial nerve is enclosed in a bony canal and lies above the oval window. The horizontal or lateral semicircular canal is situated postero lateral to the facial nerve canal. The contents of the middle ear Three ossicles, MALLEUS, INCUS and STAPES. Two muscles: the STAPEDIUS and the TENSOR TYMPANI. Two nerves: the FACIAL and the CHORDA TYMPANI. The mucosal lining of the middle ear is ciliated columnar epithelium. The mastoid air cells are peumatizations of the mastoid bone , the biggest air cell being the mastoid antrum which is always present. Other cells are variable in existence. THE INNER( INTERNAL) EAR It consists of a membranous labyrinth enclosed in a bony labyrinth. BOTH ARE WITHIN THE PETROUS PART OF THE TEMPORAL BONE. The bony labyrinth consists of the VESTIBULE which is the central portion, the BONY SEMICIRCULAR CANALS which are situated posterior to the vestibule and the BONY COCHLEA which is anterior to the vestibule. The semicircular canals, consist of SUPERIOR(ANTERIOR), POSTERIOR (VERTICAL)and HORIZONTAL(LATERAL) canals. The membranous labyrinth Contains fluid known as the endolymph. It contains the vestibular and the auditory components. The vestibular element, which is connected to the vestibular part of the 8th cranial nerve, consists of three semicircular canals, the utricle and the saccule. The auditory element consists of the cochlear duct and is connected to the cochlear part of the 8th cranial nerve. PHYSIOLOGY OF HEARING The basic function of the ear is to convert the sound energy from mechanical vibrations in the air to mechanical vibrations in the inner ear fluids (cochlear duct) and then to electrical energy in the hair cells that is transmitted to the brain via the auditory nerve. The auricle collects the sound waves. They pass through the external meatus to the TM which is set in motion. The vibrations are transmitted to the ossicles, malleus , incus and the stapes. The stapes footplate is attached to the oval window, and from it vibrations are transmitted to the inner ear fluids. PHYSIOLOGY OF HEARING Two factors are important to magnify the vibrations to overcome the resistance of the inner ear fluids. The first is the ratio between the surface area of the TM to that of the oval window. The second is the lever ratio in the ossicular chain. In the inner ear, fluid displacement caused by the transmitted waves stimulates the hair cells and the nerve terminals in the ORGAN OF CORTI. These nerve impulses are transmitted to the higher centers of hearing via the cochlear( auditory) nerve. PHYSIOLOGY OF THE VESTIBULAR APPARATUS The balance is maintained by the coordination of information from three systems: Proprioception . The eyes. The vestibular system. The vestibular system consists of three semicircular canals, the utricle and the saccule. The UTRICLE and the SACCULE respond to linear acceleration. The SEMICIRCULAR CANALS respond to angular acceleration. These nerve impulses are transmitted via the vestibular nerve to the higher vestibular centers in the brain where are interpreted with other information from other systems to keep balance SYMPTOMS OF EAR DISEASE Hard of hearing or deafness, conductive or sensorineural. Discharge, this can be caused by inflammation of the external or the middle ear. Watery discharge after head injury is caused by CSF leak. Pain, which is also called Otalgia. It can be referred. Itching, which is caused by diseases of the external ear. Tinnitus is the subjective sensation of sound in the ear. Vertigo is illusion of motion usually rotational motion. PHYSICAL EXAMINATION It is usually done with the aid of head mirror and light source or headlight, and ear speculum. Otoscope(auroscope), is also used in the examination of the ear. Sometimes, microscope is used for ear examination. HEARING TESTS These tests are done with the aid of a tuning fork 512 Hz. Two main tests are done, Rinne and the Weber tests. Rinne test is done for each ear separately and compares the air and bone conductions of a single ear( the RT and LT) ears separately. Rinne test is called positive when air conduction is better than bone conduction. Rinne test is negative when bone conduction is better than air. Weber test is the test of lateralization. Central weber occurs in normal hearing or in cases of bilateral symmetrical hearing loss. Weber is lateralized: To the side of conductive hearing loss Away from the side of sensorineural hearing loss INVESTIGATINS Audiological tests:audiogram and tympanometry. Radiological investigations: X-ray of the temporal bone and mastoid, CT scan of the mastoid and temporal bones and MRI scan. Bacteriological investigations, like swab for culture and sensitivity. DISEASES OF THE EXTERNAL EAR Congenital malformations of the external ear, like MICROTIA and ATRESIA of the external auditory meatus. Microtia. Absence of the pinna or gross deformity is often associated with meatal atresia and ossicular abnormalities. Treatment: either surgical reconstruction or prosthesis. Hematoma of the auricle It is accumulation of blood beneath the perichondrium of the auricle. It generally results from trauma to the auricle like in wrestlers. Treatment : aspiration or drainage of the blood with full aseptic technique and application of a firm bandage to the ear to prevent re collection of the blood. Surgical evacuation with quilting sutures If it is not treated properly, infection of the cartilage may occur or thickening of the cartilage leading to auricular deformity PERICHONDRITIS OF THE AURICLE It is inflammation of the perichondrium and the cartilage of the auricle. It may follow hematoma, or result from extension of infection from a boil on the posterior meatal wall or be a complication of a surgical procedure or external trauma. The causative micro-organism is Pseudomonas pyocyanea. It is manifested with severe pain in the ear with fever, the auricle is swollen, dusky colour and loses normal shape. Treatment Anti- Pseudomonas antibiotics are given with incision and drainage of any collection of pus. The External Auditory Meatus Impacted wax The accumulated secretion of the ceruminous glands May form a solid mass causing deafness and discomfort in the ear. Diagnosis is simple by clinical examination with wax having a brown or yellowish colour, but sometimes it is black or grayish. Treatment is either by instrumental manipulation of the wax which must be careful and gentle, or by ear wash. Wax solvents like olive oil. Keratosis obturans It is a hard mass of wax, desquamated epithelium and cholesterol that is found in the deep part of the bony canal. It can be unilateral or bilateral. The cause is unknown, and there is an association with bronchieactasis and chronic bronchitis in young patients. The clinical picture in manifested with pain and deafness. As the mass increases in size, erosion of the deep bony canal can occur with facial nerve exposure and even paralysis in severe cases. Treatment is removal which is usually done under general anesthesia. Wax solvents are given prior to removal to soften the wax. Foreign bodies in the ear They can be in the form of objects that are deliberately inserted into the ear, usually in young children. These can be organic or non organic. Foreign bodies can be small insects that enter the canal by accident. Treatment is removal mainly by ear wash for the non organic objects. Instrumental manipulation of the foreign bodies is also done for their removal, and general anesthesia is needed in young uncooperative children. Otitis Externa It is inflammation of the skin of the external ear , it can be a localized form or more generalized inflammation. A boil or furuncle is a localized form of infection and inflammation of a hair follicle of the external cartilaginous part of the meatus. It is caused by staphylococcus aureus and clinically is characterized by severe pain and tenderness in the external canal and auricle. Treatment: Symptomatic relief of pain by using analgesics and local heat, together with anti-staphylococcal antibiotics like cloxacillin. Topical application of local antibiotic ointment or cream will help to hasten resolution. Incision of the boil is done when it is clearly pointing to the skin surface. Diffuse otitis externa This condition occurs in acute or chronic forms. The acute form of otitis externa presents as feeling of heat, pain which is often severe and is increased by jaw movements. Thin serous discharge is accompanied by easing of the pain. The discharge later becomes thicker and purulent. Conductive deafness is usually present due to accumulation of the discharge. The chronic form is manifested by discharge and constant irritation or inching. Treatment Thorough and gentle cleansing of the external meatus, keeping the ear dry. Local preparations containing broad-spectrum antibiotics and corticosteroids are prescribed like gentamycin and dexamethasone. Ear wicks, packing the ear with ear gauze soaked with antibiotic-steroid cream. As the condition improves, the antiseptic-steroid cream may be applied twice daily to the external meatus, especially for the chronic cases. Otomycosis It is mycotic ( fungal )infection of the external canal. Predisposing factors include excessive humidity like in tropical and subtropical climates and the use of antibiotic drops in the ear. Two types of fungi are responsible for otomycosis, candida albicans and aspergillus niger. Clinically the situation is characterized by irritation and itching in the ear and failure to respond to the usual management of otitis externa. On examination, a mass of fungal debris is usually seen in the ear canal . Treatment thorough cleansing of the meatus and dry mopping. Application of local antifungal preparations like clotrimazole lotion. Regular cleansing may be needed every few days till the subsidence of the condition. Eczematous otitis externa. It is characterized by intense itching causing considerable distress. Secondary infection due to scratching of the ear usually produces a diffuse reaction. Treatment is by treating the secondary bacterial infection and application of local steroids to the ear. Otitis externa hemorrhagica It is infection of the deep external canal and the tympanic membrane, caused by streptococcus combined with a virus . it is characterized with intense pain and tinnitus. On examination, blood blisters may be seen in the deep meatal wall and the tympanic membrane which are prone to spontaneous rupture. Treatment: A course of antibiotics, like penicillin is given together with analgesia for pain. Malignant Otitis Externa It is uncommon disease mainly seen in elderly diabetics. It is characterized by increasing severe pain in the ear with purulent discharge. The responsible organism is pseudomonas pyocyanea. It is characterized by granulation tissue in the floor of the meatus at the junction of the cartilaginous and the bony parts. Infection can spread to the parotid gland and the structures at the base of the skull causing wide spread osteomylitis, intracranial complications and even death. Treatment Antipseudomonal antibiotics like ticarcilin which are given at full doses. Granulation tissues and necrotic tissues are removed regularly. Treatment of the associated medical problem ( control of diabetes). Acute Suppurative Otitis Media It is an acute infection and inflammation of the middle ear cleft. usually starts as a viral infection of the middle ear resulting from URTI, followed by secondary bacterial infection. The causative microorganism are: Streptococcus pneumonia. Haemophilus influenzae . Moraxella catarrhalis. Others, like staphyloccus aureus and streptococcus pyogenes. Predisposing factors 1-Young age, acute OM is disease of young children because the Eustachian tube is shorter, wider and more horizontal. Higher incidence of URTI. 2- Diseases of the nose and nasopharynx, like upper respiratory tract infection(URTI), allergic rhinitis and adenoid hypertrophy. Pathology and pathogenesis Eustachian tube obstruction as a result of edema from the URTI. Decreased ventilation of the middle ear occurs with consequent effusion in the ear . This effusion becomes secondarily infected with bacteria. Tympanic membrane will bulge with increased intratympanic pressure and may finally rupture causing ear discharge. Resolution of the inflammatory reaction will end in healing of the ear. In severe infections,There is destruction of the bony trabeculae of the mastoid air cells with consequent mastoiditis and abscess formation. Clinical picture The first symptom is a dull ache inside the ear which may become more severe. Marked hearing loss, fever usually occurs in young children. In infant : irritability, excessive crying and ear tugging. Examination: TM very red and in severe cases there will be marked bulging of the membrane with loss of the surface markings. If there is a perforation in the TM, there will be a copious mucopurulent discharge. Once the TM ruptures the pain will decrease to a dull ache. Management Treatment of the existing URTI. Analgesia for pain. If discharge is present, swab is taken for culture and sensitivity. Empirical treatment with broad spectrum antibiotics. Amoxicillin, amoxicillin with clavulinic acid(augmentin), second generation cephalosporin. If the patient is allergic to penicillin, macrolides and sulpha drugs like co-trimoxazole can be given. When the response to treatment is unsatisfactory, it may be that the antibiotic has to be changed according to the result of culture if present. Sometimes aspiration of middle ear discharge through myringotomy is needed. If discharge and pain persist, despite the patient having been given the appropriate doses of the correct antibiotics, a mastoid reservoir of infection may be present and needs appropriate investigations. The role of surgery in the management of acute suppurative otitis media is limited to: Myringotomy, which is perforation of the tympanic membrane to aspirate pus to relieve the pain and to get a sample for C&S. It is also the first treatment of acute mastoiditis. Cortical mastoidectomy for acute mastoiditis if the medical management and myringotomy fail. It is also needed for mastoid reservoir Otitis media with effusion( chronic middle ear effusion) Serous or secretory otitis media. Non purulent middle ear fluid, sometimes has a sticky, thick character resembling the glue, Glue ears. The basic cause is long standing or chronic Eustachian tube dysfunction or obstruction. Causes of tube obstruction are : Mass lesion in the nasopharynx, which is mainly adenoid tissue in children. Edematous swelling of the mucus membrane of the nasopharynx, Allergic rhinitis or Chronic sinusitis. Nasopharyngeal tumour, suspected in unilateral serous otitis media in adults and elderly. Eustachian tube dysfunction which usually occurs in cases of cleft palate. Clinical features Hard of hearing and deafness mainly in children. In adults, there is blocked feeling in the ear. Discomfort, occasional tinnitus or mild vertigo can be features of the disease. Symptoms of the causative etiology, like snoring due to adenoids in children and features of rhinosinusitis in adults and children. On examination Retraction of the TM, with altered landmarks. There is alteration of the normal color of the TM. Fluid level and even air bubbles may be seen behind the TM. Examination of the nose and sinuses may reveal chronic sinusitis or rhinitis. In adults , the nasopharynx should be examined to rule out the presence of nasopharyngeal carcinoma. Investigations Audiogram which usually shows conductive hearing loss. Tympanometry shows flat curve(typeB). X-Ray of the postnasal space which may show enlarged adenoids in young children. Radiography of the sinuses is indicated when sinus disease is suspected. Treatment Medical treatment is indicated first with antibiotics and management of the underlying cause like chronic rhinosinsitis. Surgery is indicated if the condition persists despite the conservative measures. Surgical treatment includes myringotomy and aspiration of the middle ear fluid, usually combined with insertion of ventilation tubes(grommets). Surgery may also be needed for the causative etiology like adenoidectomy and nasal and sinus surgery. Chronic suppurative otitis media It is a chronic infection and inflammation of the middle ear and may be the mastoid air cells. It can be classified into 2 types: Tubotympanic otitis media( chronic otitis media without cholesteatoma)or(safe ear). Tympanomastoid otitis media( chronic otitis media with cholesteatoma)or ( the unsafe ear) • Tubotympanic otitis media It is also called otitis media without cholesteatoma. Tends to follow a benign course and considered to be safe. It is a complication of acute otitis media where there is persistent perforation in the TM and persisting or recurring infection of the middle ear resulting from spread of infection via the Eustachian tube or through the perforation itself. It rarely gives rise to any serious complications. The main pathological condition in this type is a perforation of the TM. A patient with such a perforation is liable to persistent or recurrent discharge secondary to URTI, or from bacteria entering the middle ear through the perforation from the external canal. The perforation is always a central one, that is, it is surrounded by part of the pars tensa throughout its circumference. The perforation may be anterior, posterior, or subtotal, but always surrounded by TM remnant. Clinical features Mucopurulent discharge which may be intermittent or persistent . Deafness which may vary in severity depending on the site and size of the perforation and the status of the ossicular chain. O/E: Suction and dry mopping. A swab from the discharge can be submitted for culture and sensitivity test. The perforation and the middle ear mucosa can be assessed. Nose and paranasal sinuses and the pharynx: adenoids or chronic rhinosinusitis. Complications are rare and are not serious. Otitis externa: secondary to chronic ear discharge. Ossicular fixation / discontinuity. Treatment Local measures which include dry mopping and local antibiotic drops instilled into the ear. Instructions are given to the patient to avoid getting water into the ear when washing or swimming, and to avoid nose blowing when he or she gets a cold to avoid movement of the infected material up the Eustachian tube to the middle ear cavity. Treatment of the focus of infection, which includes elimination of the URTI by medical treatment. Surgery has a role when the focus needs surgical treatment like adenoidectomy or sinonasal surgery. The surgical management of TM perforation is tympanoplasty. The simplest form is myrigoplasty which is repair of the perforation of the TM using fascial or cartilage graft. The operation may be more complex with ossicular reconstruction in addition to TM repair. Cortical mastoidectomy may be indicated when there is reservoir of infection in the mastoid air cells. Tympanomastoid otitis media The bone of the attic, antrum and the mastoid process is involved a well as the mucosa of the middle ear, atticoantral disease. The main pathology of this disease is the presence of cholesteatoma, so it is also called chronic otitis media with cholesteatoma. As erosion of bone may extend to adjacent vital structures, there is always a danger of serious complications (unsafe ear). Pathology and pathogenesis The most pathological finding is cholesteatoma. It consists of a sac of keratinizing squamous epithelium surrounded by granulation tissues. The surface layers of the epithelium( which is inside) keep producing keratin causing gradual expansion of the sac. The granulation tissues on the outside of the sac produce lysozymes and this gradually erodes the ossicles, the ear drum and the mastoid bone. The most accepted theory of the origin of cholesteatoma is the retraction pocket theory. When the Eustachian tube is blocked, the TM tends to retract in the thin pars flaccid in to the attic region. With gradual increase in the size of the sac, it passes to the mastoid antrum and the mastoid bone. Clinical features Ear discharge: recurrent or persistent, the discharge is purulent and may be scanty, and it is frequently foul smelling. Hard of hearing, may vary in severity. Bleeding from the ear may occur when there is granulation or polyps. On examination The perforation is usually marginal, in the attic or posterosuperior segment of the TM. It extends to the bony margin of the drum. Polyps or granulation tissues may be seen . Cholesteatoma may be seen as a grayish( typically pearly white)substance, projecting from or filling an attic or a marginal perforation. Investigations Hearing tests : tuning fork and Audiogram. Radiography : X-Ray of the temporal bone and mastoid. Now CT scan of the temporal bone is widely use to investigate mastoid disease as it shows the details of the disease and detailed anatomy of the temporal bone. Soft tissue opacity Scutum erosion Ossicles eroded Tegmen intact Erosion into HSCC Cholesteatoma with fistula Treatment Local measures which involve cleaning the ear of discharge and the assessment of the status of the TM. This is usually done with the aid of the microscope and involves removal of polyps and granulations. This procedure is called SUCTION CLEARANCE. Local antibiotic drops, according to the results of swab culture. Most cases of cholesteatoma requires surgery. The operation needed is usually modified radical mastoidectomy . Skin flap Periosteal flap Complication of otitis media These complications can follow either acute or chronic otitis media. With the advent of antibiotic therapy, these complications are now rare with the acute otitis media. Nowadays these complication are mostly associated with chronic otitis media with cholesteatoma ( unsafe ear). These complications can be classified into extracranial and intracranial complications. Extracranial complications Mastoiditis: which is inflammation of the mastoid bone with even mastoid abscess formation. Petrositis: which is inflammation of the petrous temporal bone . Labyrinthitis : which is inflammation of the inner ear with consequent vertigo and sensorineural deafness. Facial nerve paralysis: which is due to pressure effect of the cholesteatoma on the facial nerve, especially when it is dehiscent. Mastoiditis It can be acute or chronic. Infection involves the bony walls of the cells of the mastoid process. The acute form usually follows AOM and inflammatory reaction can be severe to cause break down of the trabeculae of air cells resulting in mastoid abscess. Clinical picture Increasing or recurring pain and tenderness over the area of the mastoid antrum, tip or posterior border. Fever and rising pulse rate in children. Deafness. Edema and displacement of the auricle forwards and downwards. Stenosis and Sagging of the posterosuperior canal wall. If abscess is present fluctuant swelling is present. Treatment Antibiotic treatment, C&S. Drainage of pus. Cortical mastoidectomy When medical treatment fails, increasing fever and pulse rate, sagging of the meatal wall, labyrinthine or intracranial complicstions, onset of facial paralysis, persistent OM, and ptrogressive deafness. Intracranial complications Meningitis. Extradural dural abscess. Subdual abscess. Brain abscess. Lateral sinus thrombosis. Cortical thrombophlebitis. Otitic hydrocephalus Otosclerosis It is a common disease 1:200 of general population. It usually affects the age from 18-30. Etiology Sex: it affects females more than males. There is a marked hereditary tendency. There is association between the onset of the disease with the onset of puberty and pregnancy( possible hormonal effect). Pathology First the normal bone is absorbed and replaced by a vascular spongy osteoid bone. Later the new bone becomes thicker and less vascular. The most common site is the region of the anterior margin of the oval window which is the site of the ( fissula ante fenestram) which could be the region of anastomosis of vessels between the middle ear and the inner ear, or it could be the site of vestigial cartilaginous remnant which is prone to otosclerotic changes. Symptoms and Signs Gradually increasing deafness. There may be tinnitus especially in rapidly progressing disease. Paracusis Willisii: means the patient states that he can hear better in noisy environment. Vertigo is a rare symptom of the disease. The patient usually speaks in a low, well modulated voice. The TM is usually normal, yet in 10% of cases there is a flamingo-pink blush may be seen behind the TM on the promontory which is due to hyperemia and indicates an active phase of otosclerosis Note: Otosclerosis may coexist with other middle ear problems like TM perforation. Tuning fork test: It shows negative Rinne test, and Weber is lateralized to the affected ear. Investigations: Audiogram usually shows conductive hearing loss with Cahart notch. Tympanometry typically shows low compliance impedance curve. Treatment Treatment Is usually with a hearing aid or surgery. The surgery is stapedectomy. SENSORINEURAL DEAFNESS The cause of this deafness is in the cochlea or in the auditory nerve. Sensory deafness refers to cochlear origin Neural or retrocochlear deafness refers to nerve origin. The disability of the sensorineural deafness is greater than that of conductive deafness. A patient with a sensorineural deafness hears with more difficulty in the presence of background noise. Tinnitus is present in many patients. Recruitment means intolerance of loud sounds and generally is associated with cochlear lesion. Lesion in either site will reduce the discrimination for speech, but it is more marked in neural lesions. Causes of sensorineual deafness Infection Viral deafness: Mumps sudden sensorineural deafness which is usually unilateral. The hearing loss is usually severe to profound and is usually permanent. Measles, is a less common cause than mumps, and can cause bilateral high frequency hearing loss and is usually severe and permanent. Herpes zoster oticus( Ramsay Hunt syndrome): is a reactivation of herpes zoster virus in the geniculate ganglion. It is manifested by a lower motor neuron facial palsy, herpetic vesicles on the external canal and the inside of the cheek, vertigo, and severe sensorineural hearing loss. Bacterial infections Suppurative labyrinthitis, it is usually a complication of chronic otitis media with cholesteatoma. It can be serous( non purulent) labyrinthitis which can be treated by prompt antibiotic therapy together with surgery( mastoid surgery). In purulent labyrinthitis there is suppuration within the labyrinth, and is associated with irreversible severe to profound hearing loss and vertigo. The treatment consists of proper antibiotic therapy and surgery to eradicate the source of infection and to prevent its spread. Syphilis Can cause deafness both in its congenital and acquired forms. The hearing loss is bilateral and progressive, and diagnosis is aided by serological tests. Treatment is both antibiotic treatment, and steroids. Presbyacusis It is hearing loss resulting from degenerative changes of aging that affects the cochlea, the auditory nerve or both. The hearing loss is symmetrical in both ears and progression is usually slow. The onset can start after the third decade. Characteristically old people complain of difficulty in understating speech because of the inability to hear high frequencies ((consonant sounds)). They have difficulty in hearing in the presence of background noise. Recruitment of hearing also adds to the distortion. Treatment is by hearing aids. Noise induced hearing loss Exposure to loud noise can lead to SNHL. It usually starts as temporary loss of hearing in the region 4-6 kHz, which is often accompanied by tinnitus. This is known as temporary threshold shift, and is usually reversible. If the exposure is repeated and prolonged, a permanent threshold shift may occur. The loss usually starts in the region of 4-6 kHz and typically produce the acoustic dip or notch in the audiogram. Later on the damage progress and the lower as well as the higher frequencies are affected. The hearing loss is roughly symmetrical in both ears, except in certain circumstances in which one ear is receiving the injurious noise more than the other as in shooting. In occupational cases, the workers should be instructed to have ear protection like the use of earmuffs, together with routine audiometry. In blast injury, there is usually perforation of the TM with consequent conductive HL. frequently inner ear injury with consequent SNHL which may be severe and permanent and is mostly marked in the higher frequencies. Surgical trauma Injury to the inner ear resulting in SNHL is a risk in every ear surgery. Ototoxicity Drugs can cause sensrineural hearing loss Aminoglycosides and Chemotherapeutic agents. Loop diuretics (ethacrinic acid and frusemisde). Beta blockers and Antiepileptics. Quinine and salicylates. Topical ear drops containing ototoxic antibiotiocs like neomycin, gentamycin, polymyxin and framycetin. No convincing evidence that these topical medications can cause sensorineural hearing loss. Sudden idiopathic hearing loss Sudden HL that the patient is aware of the onset. It is associated with tinnitus. Any pattern of hearing loss can be found on audiometry. Patients with greater loss at high frequency have a poorer prognosis than those of low- frequency loss. In most cases there is quick recovery from deafness within hours, days or weeks. If there is no recovery within 3 weeks it is unlikely to occur spontaneously. The exact etiology is unknown, presumed vascular causes and immune process are implicated. Causes like acoustic neuroma, viral causes, perilymphatic fistula should be excluded. The treatment consist of hospital admission, infusion of low molecular weight dextran and steroid treatment if there is no contraindications. To have a reasonable chance of success this should begin within one week of the original episode of sudden hearing loss. Intratympanic steroids. Hearing aids They are electroacoustic devices used to amplify sounds. The basic component of a hearing aid are: a receiver( a microphone), an amplifier, a sound transmitter, and a power source. Most current aids amplify sounds in the frequency range 2504000 Hz. They can be of several types: Postaural HA, also called behind the ear, which are the most common in use. In the ear HA, these aids sits in the concha, or canal. Body worn aids. Spectacle aids. Osseointegrated HA,also called bone anchored HA, which transmit sounds directly into the bones of the skull. Cochlear Implants A cochlear implant is a device used to stimulate residual neural tissue in patients with a profound hearing loss. Their major benefit are as aids to lip reading and in the recognition of some environmental sounds. It consists of 2 parts: an external part, and an implanted part. The external part consists of a power source, microphone sound receiver and a microprocessor which filters, analyses, and codes the sound and then passes it to an external transmitter. The implanted part consists of a receiver with a stimulating and ground electrodes. The connection between the two is through the skin of the scalp, more often by transcutaneous induction method. Rehabilitation is of paramount importance for the success of CI. Tinnitus It is the sensation of sound not brought about by simultaneously externally applied mechanoacoustic or electrical signals. This definition excludes vascular sounds. Almost every ear disease and cause of deafness can be associated with tinnitus. Tinnitus can be the major annoyance and the presenting symptom. In some patients it may lead to depression and occasionally to suicide. The first essential in the treatment is to make an accurate diagnosis. The diagnosis can be easy and its treatment can solve the problem, like wax removal, treatment of otitis media or externa, and Eustachian tube obstruction If the cause is not obvious on examination, audiological tests are done to find the cause. When the tinnitus is associated with sensorineual hearing loss, the choice treatment is between hearing aid or tinnitus masker or a combination of the two. Medical treatment for tinnitus is not always rewarding, labyrinthine sedatives like betahistin hydrochloride and cinnarizine are used in the treatment. Even antidepressants may be used in cases of depression due to tinnitus Vertigo( Dizziness, giddiness) It is illusion of movement of the patient’s body or the patient’s environment. It can be the sensation of linear motion as in tending to stagger to one side. Physiology of vestibular system Normal balance is maintained by input from the visual, vestibular and proprioceptive system in muscles and joints. These are integrated and modulated in the brain stem, cerebellum and higher cortical centres. Central (Non-otological) CVS, CNS. Peripheral (vestibular, otological) Infective: Labyrinthitis, and vestibular neuronitis. Neoplastic: acoustic neuroma. Metabolic: Meniere’s disease. Toxins: vestibulotoxic drugs. Trauma: head injury. Miscellaneous: benign paroxysmal positional vertigo. Vestibular neuronitis This condition is characterized by a severe vertigo of sudden onset without deafness or signs of neurological involvement. Aetiology The condition is thought to result from a selective inflammation of the vestibular nerve, presumably of viral origin following a vague URTI. Clinical picture Preceded a week or 10 days earlier by an URTI. Vertigo which can last several days before a gradual recovery begins ,,Nausea and vomiting. Absence of aural symptoms. Examination; Spontaneous nystagmus of the vestibular type. Investigations Caloric test: canal paresis on the affected side. Treatment Reassurance and explanation while waiting for recovery to occur by compensation. Antivertigo drugs: prochlorperazine (stemetil), cinnarzine (stugeron) and betahistine (betaserc). Prognosis Vestibular neuronitis has no complications and recovery is usual in a few weeks. Benign Paroxysmal Positional Vertigo Recurring paroxysmal short lived attacks of vertigo provoked by certain critical positions of the head. Aetiology: Idiopathic, Head injury, Viral infection, Aging process. Pathology The disease is thought to be due to displacement of otoliths (calcium carbonate particles) from the utricle and saccule to the cupula of the posterior semicircular canal. Clinical picture Brief attacks of vertigo when the patient puts his head in the critical position. Examination Dix-Hallpike test: The patient sits on a coach and the head is turned 45 towards the examiner and taken backwards into the provokating position 30 below the horizontal. The patient is instructed to keep the eyes open and focused on examiner’s eyes or forehead. Treatment Medical: Antivertigo drugs: prochlorperazine (stemetil), cinnarzine (stugeron) and betahistine (betaserc). Repositioning maneuver: Epley maneuver Meniere’s Disease This disease is characterized by paroxysmal attacks of vertigo associated with deafness and tinnitus. French physician Prosper Meniere, 1861. Pathology There is dilatation of the endolymphatic compartment of the inner ear. The aetiology of this endolymphatic hydrops is unclear, but it's presence infers an abnormality of endolymph formation or absorption. Clinical picture Usually unilateral, other labyrinth is eventually affected. Vertigo: is of sudden onset and the attack lasts for a few hours. Hearing loss: sensorineural. Tinnitus: referred to the affected ear, precedes or accompanies the vertigo. Aural fullness Otoscopy: normal. Investigations Audiological (pure tone audiometry): sensorineural hearing loss. Vestibular (caloric test): canal paresis in the affected ear. Treatment The acute attack. Bed rest. Antihistamine labyrinthine sedatives: prochlorperazine (stemetil) and cinnarzine (stugeron). Anxiolytics: I.V.diazepam. The long term management. Vasodilator drugs: betahistine hydrochloride (serc) which increases the cochlear blood flow. Reduction of labyrinthine hydrops: fluid and salt limitation with diuretics. II. Surgical Endolymphatic sac decompression or shunt. Vestibular nerve section.