Hydrocephalus

Question 1

Define hydrocephalus

Answer 1

an excessive accumulation of CSF within the head caused by disturbance of formation, flow or absorption, high pressure and ventricular dilation result

Question 2

Cerebral perfusion pressure =

Answer 2

MAP – ICP

Question 3

Define communicating hydrocephalus?

Answer 3

CSF is inefficiently absorbed back into the blood stream causes include meningitis or subarachnoid haemorrhage

Question 4

Define non communicating hydrocephalus?

Answer 4

this is obstructive, CSF is blocked from flowing between one of the passages that connects the ventricles e.g. tumours and other lesions

Question 5

What are three congenital abnormalities that can cause hydrocephalus?

Answer 5

The Arnold-Chiari malformation
Congenital Stenosis or atresia of aqueduct of sylvius (connects 3rd and 4th ventricles)
Atresia of the foramina of magendie and luschka

Question 6

Explain arnold chiari malformation?

Answer 6

there is prolongation of the cerebellum and the medulla bulging through the foramen magnum which obstructs the flow of CSF in the posterior fossa, associated with spina bifida (myelomeningocele)

Question 7

Explain congenital stenosis or atresia of the aqueduct of sylvius?

Answer 7

this is what connects the 3rd and 4th ventricles so there is dilation of the 3rd and lateral ventricles

Question 8

Explain atresia of foramina of magendie and luschka?

Answer 8

Leads to dilatation o the 4th, 3rd and lateral ventricles

Question 9

List some acquired causes of hydrocephalus?

Answer 9

posterior fossa and brainstem tumours
subarachnoid haemorrhage
a 3rd ventricle colloid cyst
choroid plexus papilloma

Question 10

Describe presentation of hydrocephalus in an infant and young child?

Answer 10

The pliable skull expands to accommodate the enlarging brain
There is great enlargement of the head with prominent scapulas veins and forehead overhanging the eyes, the fontanelles remain open.

Question 11

Describe presentation of hydrocephalus in an older child and adult?

Answer 11

Enlargement of the brain is prevented by the inability of the skull to expand. The main change is dilation of the ventricles associated with the effects on the brain of increased ICP.

Question 12

Describe management of hydrocephalus?

Answer 12

ventriculoperitoneal or lumbar peritoneal shunting is necessary when progressive hydrocephalus causes symptoms. Removal of tumours is carried out when appropriate. Endoscopic 3rd ventriculostomy may be performed.

Question 13

What is normal pressure hydrocephalus also known as ?

Answer 13

hydrocephalus ex vacuo

Question 14

Describe normal pressure hydrocephalus?

Answer 14

a syndrome of enlarged lateral ventricles in elderly patients with a triad of symptoms of gait apraxia, dementia and urinary incontinence. CSF pressures are usually at the high end of normal range. Shunting may be required.

Question 15

Describe secondary hydrocephalus?

Answer 15

Ventricular system enlarges to compensate for loss of cerebral tissue in generalised cerebral atrophy
no increase in pressure