Hydrocephalus Flashcards
What is CSF
clear fluid found in ventricles and subarachnoid space
How much CSF will ventricles normally contain?
25 ml in each
What cells produce CSF?
- modified ependymal cells
- which form the choroid plexus
- can also arise from interstitial fluid
What are the constituents of CSF?
- very similar biochemistry to blood
- far fewer proteins or WBC
- increased Mg
- decreased Ca
Where is the choroid plexus located?
- lateral ventricles
- not in third or fourth
What drug can reduce CSF production?
- acetazolamide (carbonic anhydrase inhibitor)
- remifentanil
- noradrenaline
What can increase CSF production?
- volatile anaesthesic agenst
- NO
- hypercapnoea (CO2 retention)
What is the function of CSF?
- provides buoyancy to lighten weight of brain
- protects from acc/dec injuries
- removes waste from brain
- forms pressure buffer to reduce brains impact on ICP
Where does CSF drain after the fourth ventricle?
- cisterns then through arachnoid granulations into dural venous sinuses
- carried in venous blood and recycled
How does flow of CSF depend on pressure?
- raised ICP means increased flow of CSF
- raised venous pressure can get back flow from venous sinsuses
What is Hydrocephalus?
increase in CSF in the head which results in increased ICP
When is hydrocephalus most common?
- birth (often treated before birth)
- patients with Spina Bifida
What can hydrocephalus result in if untreated?
neurological deficits and cognitive disorders
What are the causes of hydrocephalus?
- Communicating blockage
- Non-communicating blockage
- Congenital
- Acquired
What is the difference between communicating and non-communicating blockages?
Communicating - blockage to CSF resorption in arachnoid granulations/overproduction
Non-communicating - blockage within pathway