Download AJLAN`S LEC Common Congenital CNS Problems2011

COMMON CONGENITAL
NEUROSURGICAL DISEASES
Essam Elgamal
428 surgery team
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Outline
 Approach to Congenital Neurosurgical Diseases
 Development of the Nervous System
 Congenital Malformations
 Neural Tube Defect
 Congenital Hydrocephalus
 Arnold Chiari Malformation
 Dandy-Walker Cyst
 Arachnoid Cyst
 Craniosynostosis
 Neurocutaneous Syndromes
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What can go wrong with the brain?
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 Abnormal development
 Neural Tube Defects
 Neuromigrational Disorders
 Pernatal Events
 Cerebral palsy
 Abnormal functioning
 Seizures & Epilepsy
 Hydrocephalus
 Abnormal programming
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Neurofibromatosis
Tuberous Sclerosis
Sturge-Weber Syndrome
Mitochondrial Disorders
Development of the Nervous System
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Gross Development
 Ectoderm
 Will form nervous system and outer skin
 Endoderm
 Will form skeletal system and voluntary muscle
 Mesoderm
 Will form gut and digestive organs
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Developmental Sequence
 Neural plate invaginates as
neural folds push up
 Neural folds eventually form
neural groove
 Cells of neural fold eventuall
meet
 Form the neural tube
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Developmental Sequence
 Neural tube runs anterior – posterior along embryo
 Surrounding ectoderm eventually encloses neural
tube
 When neural tube closes off brain and spinal cord are
formed
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Human Embryo
 Primitive brain consists of
3 cavities that will form
ventricles
 Brain’s gross features are
then formed through a
series of bends
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Human Embryo
 Developing embryo
 Goes through a series of
folds or “flexures”
 Gives rise to the compact
structure of the brain
Brain
Diencephalon
Midbrain
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Congenital Malformations
Neural Tube Defects (the most
common defect)
(Dysraphism)
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Pathophysiology
 Spina bifida occulta (closed)
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5-10% of population 1/1000 in US, 2/1000 in ksa
not clinically significant
tuft of hair, dimple sinus or port wine stain
high incidence of underlying defect
no treatment required just to cover it, U/S or MR
Pathophysiology
 The openings at each end are termed the rostral and
caudal neuropores, and close at around the 24th and 27th
days respectively
 If the neural folds do not fuse at the rostral end,
anencephaly results
 If the neural folds do not fuse at the caudal end,
myeloschisis (cleft spinal cord) results (the most severe
form of spina bifida) treated as an emergency case, just
few hour after delivery
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anencephaly
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If it doesn’t get
closed =
myeloschisis
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•Failure of vertebral
arch bony growth and
fusion.
•Neurologic symptoms
are usually absent,
although problems may
occur during growth
owing to "tethering" of
the spinal cord.
•Skin anomalies
frequently overlie the
defect, including a hairy
patch, hemangioma, or
dermal sinus
Same as B +Spinal
cord and its nerves
enter the defect
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Meninges with
CSF bulge
through the
defect coverd by
skin
Neural tissue is
directly exposed
 Multiple factors implicated:
not well understood
 Folate deficiency (most common cause)
(there is no benefit to give folic acid after 24th-27th day)
 Radiation & chemicals
 Drugs
 Malnutrition
 Genetic determinants (mutations in folate-responsive
or folate-dependent pathways)
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Diagnosis
 Maternal Alpha Fetoprotein
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AFP leaks into amniotic fluid, and then into maternal blood in case of open spina bifida
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Blood level taken 13-16 weeks gestation is used as a screening test;
 Amniocentesis
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at around 18 weeks, allows detection of over 99 percent of fetuses with neural tube defects
 Ultrasound
 MRI
U.S is the first way to detect neural tube defect
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M.R.I is the confirmatory method to detect neural
tube defect
Associated anomalies
 Assess for presence & severity of
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Chiari Malformation
Hydrocephalus
Associated brain malformations
Extremity deformities: contractures
Congenital kyphosis and/or scoliosis
Other abnormalities (renal, bowel, bladder, cardiac)
Chiari II Malformation
•Cerebellar tonsil Herniation plus
Medulla distortion and dysplasia
• Seen in >50% of children with
lumbar myelomeningocoeles
•Hydrocephalus results from
aqueduct stenosis or an obstruction
of outflow of CSF from 4th ventricle
secondary to herniation
•Symptoms of raised ICP,
oropharyngeal dysfunction, cranial
nerve palsies, cardiorespiratory
failure
•Dx by MRI
•Rx by Posterior fossa
decompression & VP shunt
Chiari I Malformation
•Cerebellar herniation through
foramen magnum
•Incidental finding: headache; neck
pain; oropharyngeal dysfunction
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•Diagnosed in adulthood
Further Assessment
 Latex Allergy (gloves) (all children with spina bifida are considered to
have allergy to latex till prove otherwise )
 Seizures
 Nutrition: obesity or malnutrition
 VP shunt dysfunction
 Psychosocial development
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Clinical manifestations
 Sacral and Low Lumbar (L4, L5)
most common site
 Ambulate into adulthood
 Ankle/Foot orthoses (device to support limb function)
 Mid-lumbar (L3, L4)
 Difficulties with ambulation into adulthood
 As above plus crutches/walker
 Wheelchair for distances
 High lumbar & Thoracic (L2 & above)
 May be trained to ambulate in early childhood
 Hip-knee-ankle orthoses
 Walker or crutches but most wheelchair-bound
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Encephalocele
 Encephalocele = A sac with a part of brain but this part
doesn’t work
 Usually occipital
 may contain occipital lobe, or cerebellum
 often associated with hydrocephalus
 Immediate treatment if ruptured to prevent infection
 outcome depends upon contents
 Meningeocele in skull = A sac in the skull with no brain
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Congenital Hydrocephalus
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 Enlargement of brain ventricles (internal
hydrocephalus) and/or subarachnoid spaces
(external hydrocephalus), associated with
increased ICP.
 The incidence 0.9 and 1.8/1000 live births.
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RATIONALE
 CSF secretion is an active process.
 70% by ventricular choroid plexuses,
 30% by extrachoroid sources
 capillary ultrafiltrate,
 ependyma,
 metabolic water production
 rate of production is 0.35 ml/min or 500 ml/day.
 350ml/day reabsorbed
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QuickTime™ and a
Microsoft Video 1 decompressor
are needed to see this picture.
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 CSF is passively absorbed by:
 arachnoid villi into venous dural sinuses
 other pathways of absorption:
 spine venous plexuses.
 perivascular and the perineural sheaths.
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 PATHOPHYSIOLOGY
1. CSF overproduction:
hypervitaminosis A,
choroid plexus tumors.
2. Obstruction to CSF flow.
ventricular dilatation generates mechanical damages
to the parenchyma.
3- decreased absorption by adhesion (N:B: adhesion
occur in case of trauma, infection,& hemorrhage )
4- DVT in dural veinous sinusis
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Clinical manifestations depends on
age
 Infants & young children:
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1. Increasing head circumference.
2. Irritability, lethargy, poor feeding, and vomiting.
3. Bulging anterior fontanelle.
4. Widened cranial sutures.
5. McEwen's cracked pot sign with cranial percussion.
(palpable separation of cranial suture, percussion of the skull evokes a
'jagged' sound)
6. Scalp vein dilation (increased collateral venous
drainage).
7. Sunset sign (forced downward deviation of the eyes,
a neurologic sign almost unique with hydrocephalus).
8. Epidsodic bradycardia and apnea & HTN . Occur
later in life
Treatment
 Endoscopic third ventriculostomy
 CSF diversion:
 V-P shunt
 V-A shunt
 V-Plural shunt
 V-sinus shunt
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QuickTime™ and a
decompressor
are needed to see this picture.
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Chiari malformation
type II chiari malformation associated with lumbar
myelomeningocoeles and may be ended up with
hydrocephalus
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Dandy-Walker cyst
 Cyst in cerebellar area  no cerebellum =
cerebellar agenisis
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Arachnoid cyst
 Incidentally Dx, conservative Rx
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Craniosynostosiss
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Neurocutaneous
Syndromes
Tuberous Sclerosis
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Neurocutaneous
Syndromes
Neurofibromatosis Type 1
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Café au lait spot
Neufibromas
Lisch nodule
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Optic glioma
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Thank you abo-7med
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