Hydrocephalus and CSF Flashcards
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
Pathology of hydrocephalus
What is the flow of CSF
CSF produced by cerebral ventricles,
Flows downward to central canal of spinal cord,
Then moves outinto the subarachnoid space where it is resbasorbed by aracnhoid granulations into venous blood (through the dural venous sinus).
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
Causes of hydrocephalus in children
Congenital malformations
Meningitis
Haemorrhage
What are congenital causes of hydrocephalus?
- Arnold-Chiari Malformation
- Stenosis of the aqueduct of Sylvius
- Dandy–Walker syndrome.
- Encephalocele, meningocele
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?
- Congenital
- 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
- Irritability
- Encorged scalp veins
- CNVI palsy
- Perinaud’s syndrome
- Brisk reflexes
- Respiratory problems
What is perinaud’s syndrome?
Syndrome of:
- Upward gaze palsy
- Convergent nystagmus
- Eyelid retraction
What are features of hydrocephalus in adults?
Can be asymptomatic. If symptomatic:
- Increased ICP
- Headaches
- Papilloedema
- Visual distrubance
- Ataxia/Gait apraxia
- Upgaze/Abducens palsy
- Impaired consciousness
How would you investigate for hydrocephalus?
- MRI/CT - 1st line, pattern of ventricular enlargement. May also show cause of tumour.
- Consider LP if safe
How would you manage someone with hydrocephalus?
- Diuretics - Acetazolamide, Furosemide
- Surgery
What surgical options are available for managing someone with hydrocephalus?
- Obstruction removal
- CSF Diversion
- IIIrd ventriculostomy
- Shunt insertion - small tube draining excess CSF from ventricle in brain to another part of body (usually right atrium)
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?
Ventriculoperitoneal shunt
Where is CSF absorbed?
Arachnoid villi/granulations
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
- Headache
What are features of upward hernation?
Cerebellum herniates upward through tentorial opening with midbrain, causing:
- Nausea/Vomiting
- Progressive stupor
What are features of tonsillar herniation (coning)?
Herniation of cerebellar tonsils through foramen magnum, causing:
- Hypertension
- Bradycardia
- Bradypnoea
- Resp arrest
- Coma
- Bilateral arm dysaesthesia
