CSF..ICP..and More

Normally ICP can rise to 80-100mmHg just when coughing/straining,think of neuro patients when they cough on the tube....

CSF is produced at 500 ml/day with a total of 150 ml in the system. This means there’s continuous circulation reabsorption.


The two types of hydrocephalus are:

• obstructive – expect big lateral ventricles and normal 4th as there’s a blockage somewhere
• communicating – general big ventricles but all the piping is OK, it’s the filter/drain that’s blocked – think blood pluggin the arachnoid villi.

one of the earliest clinical signs of raised ICP is reduced venous pulsation on fundoscopy – good luck with that…

the old hyperventilation to reduce pCO2 and reduce ICP is a bit dodgy as it also does exactly what you don’t want it to do – it reduces cerebral blood flow.

mannitol has two actions

1. volume expander
2. osmotic diuretic

if osmolality is already >320 then mannitol won’t work.

steroids work for vasogenic oedema from tumours but not anything else