What is hydrocephalus?
Excessive accumulation of CSF within the head caused by disturbance of formation, flow or absorption. The result is ventriular dilatation and high prssure within the skull
What are congenital causes of hydrocephalus?
- Arnold-Chiari Malformation
- Stenosis of the aqueduct of Sylvius
- Dandy–Walker syndrome.
What is arnold-Chiari Malformation?
Cerebellar tonsils descend into the cervical canal, blocking drainage of the ventricular drainage system. Associated spina bifida is common. Syringomyelia may develop
What can cause stenosis of the sylvian aqueduct?
- Acquired neonatal meningitis/haemorrhage
What is dandy-walker syndrome?
Cerebellar hypoplasia and obstruction of the IVth ventricle outflow foramina
What are features of hydrocephalus in children?
- Enlarged head
- Bulging fontanelles
- Encorged scalp veins
- CNVI palsy
- Perinaud's syndrome
- Brisk reflexes
- Respiratory problems
What is perinaud's syndrome?
- Upward gaze palsy
- Convergent nystagmus
- Eyelid retraction
What are features of hydrocephalus in adults?
Can be asymptomatic. If symptomatic:
- Increased ICP
- Visual distrubance
- Ataxia/Gait apraxia
- Upgaze/Abducens palsy
- Impaired consciousness
What can cause hydrocephalus in adults?
- Posterior fossea/brainstem tumours - outflow obstruction
- SAH - obstruction
- Head injury - obstruction
- Meningitis - obstruction
- IIIrd ventricle colloid cyst
- Choroid plexus papilloma
How would you investigate for hydrocephalus?
- Consider LP if safe
How would you manage someone with hydrocephalus?
- Diuretics - Acetazolamide, Furosemide
What surgical options are available for managing someone with hydrocephalus?
- Obstruction removal
- CSF Diversion
- IIIrd ventriculostomy
- Shunt insertion
What is a third ventriculostomy?
A surgical procedure for treatment of hydrocephalus in which an opening is created in the floor of the third ventricle using an endoscope placed within the ventricular system through a burr hole. This allows the cerebrospinal fluid to flow directly to the basal cisterns, bypassing the obstruction. Specifically, the opening is created in the translucent tuber cinereum on the third ventricular floor.
What is the most common type of shunt that is inserted for treating hydrocephalus?
What are complications to shunt insertion?
- Over-drainage - low-pressure headaches, SDH
- Abdominal hernias
What is normal pressure hydrocephalus?
Syndrome caused by expansion of the lateral cerebral ventricles and distortion of the fibers in the corona radiata. Its typical symptoms are urinary incontinence, dementia, and gait disturbance. CSF pressure is usually normal. Ventricles are chronically dilated.
The name is a misnomer - low-grade hydrocephalus with intermittently raised ICP
What are the classic features seen in normal pressure hydrocephalus?
- Gait disturbance - apraxia
- Urinary incontinence
How would you manage someone with normal pressure hydrocephalus?
What are indications for LP?
- Suspicion of meningitis
- Suspicion of SAH
- Suspcicion of CNS disease - guillian barre, carcinomatous meningitis
- Therapeutic relief
What are contraindications to LP?
- Bleeding diathesis
- Signs of raised ICP
- Infection around puncture site
- Vertebral deformities
Where is CSF produced from?
Choroid Plexus - 80%
Ependymal lining of the ventricles - 20%
Where is CSF absorbed?
What are features of uncal herniation?
Innermost part of temporal lobe herniating, casuing:
- CNIII palsy
- Contralateral hemiparesis - compression of contralateral cerebral crus
- Decerebrate posturing
What are features of central herniation syndrome?
Diencephalon and parts of temporal lobe of both hemispheres herniate through tentorium cerebelli, causing:
- Medium sized, fixed pupils
- Decorticate posturing
- Upward gaze palsy
- Early coma
What are features of Cingulate/Subfalcine herniation?
Innermost part of frontal lobe herniates under part of falx cerebri, causing:
- Contralateral leg paralysis
What are features of upward hernation?
Cerebellum herniates upward through tentorial opening with midbrain, causing:
- Progressive stupor
What are features of tonsillar herniation (coning)?
Herniation of cerebellar tonsils through foramen magnum, causing:
- Resp arrest
- Bilateral arm dysaesthesia