Hydrocephalus Flashcards
Where is CSF produced
choroid plexus (pia mater)
What is the distribution of CSF between intracranial and spine in adults?
50% intracranial
50% spinal
What is the volume of CSF in adults?
150mls
At what rate does the choroid plexus produce CSF?
450mls/day (3-4x turnover)
How much of a sample of CSF can you take?
up to 20 ml
What is the function of CSF?
Buoyancy (stops brain from crushing itself)
Protection
Reservoir for maintaining ICP
Excretion of metabolic waste
Exit route for pineal secretions to the pituitary gland
Where is the choroid plexus located?
Choroid plexus found in each of the four ventricles:
lateral ventricles
third ventricle
fourth ventricle
Where is CSF absorbed?
arachnoid granulations in the superior saggital sinus
In which compartment does CSF flow?
subarachnoid space
What are the two types of flow of CSF?
Bulk flow (inside of brain to outside) and pulsatile flow (and in time with heartbeat)
Where is CSF produced in infants?
via minor pathway. Major pathway in adults is via choroid plexus
At what age does the major pathway for production and absorption of CSF take over?
2 years
How is Hydrocephalus classified?
communicating and non-communicating/obstructive
ateiological
In which cause of hydrocephalus can you safely perform LP?
communicating (not obstructive!!)
How to distinguish between raised ICP and hydrocephalus?
only by imaging! Hydrocephalus will present with similar symptoms and signs as raised ICP
Which imaging is used for raised ICP/hydrocephalus?
CT or MRI
Why can you perform a LP in communicating but not obstructive hydrocephalus?
continuous gradient of pressure in communicating (same pressure in spinal cord and brain) whilst in obstructive there is a gradient of pressure- high in head and low in spinal cord, therefore removing fluid could increase gradient and brain structures could be forced downwards
Which structure is at risk if you perform LP in patient with obstructive hydrocephalus?
basilar artery, causing brainstem stroke
Name one aetiological cause of hydrocephalus
chiari malformation or spina bifida aqueductal stenosis (x-linked) Dandy walker complex Congenital arachnoid cysts Atresia of foramen of munro
Name two acquired causes of hydrocephalus
haemorrhage
traumatic head injury
infection
tumour
What are the symptoms of hydrocephalus
exactly the same symptoms as for raised ICP headache nausea and vomiting blurred vision drowsiness or reduced GCS developmental delay
What is Parinaud’s syndrome?
inability to move the eyes up and down= setting sun sign. Sign of hydrocephalus
What is the management of hydrocephalus?
Eliminate obstruction (ventric tumour)
Divert CSF flow elsewhere (shunt)
Reduce production of CSF (choroid plexectomy)
How can you divert CSF flow?
external ventricular drain, very quick and easy procedure
