What is the mean CSF pressure?
- 14cm CSF.
Values above what level indicate abnormally high CSF pressure?
> 15mmHg or >20cm CSF.
Rate of CSF formation per minute?
0.35ml/min.
What forms CSF?
- Brain ISF (25%).
What drug reduces CSF production by >50%?
Acetazolamide.
CSF undergoes substantial absorption via?
Arachnoid granulations.
CSF absorption depends upon?
ICP being greater than the pressure in sagittal sinus.
Valsalva like manoeuvres have what effect on the brain?
Transient venous engorgement.
Physical functions of CSF?
- Accommodation of physiological changes in vascular volumes in the head (- displaced into spinal canal).
Chemical functions of CSF?
Spinal arachnoid webs may be idiopathic or secondary to what?
Previous inflammatory processes due to infection or intracranial haemorrhage.
Due to the spinal arachnoid web CSF in the spinal canal is unable to disperse normally, leading to what?
Focal hydraulic pressure on the spinal cord.
Give an example of a CNS water pathology where there is an abnormal accumulation of water within parenchyma of CNS.
Classification of hydrocephalus?
Practically speaking, hydrocephalus should be labelled as communicating only if?
It can safely be decompressed via lumbar puncture.
What physical signs at birth may suggest hydrocephalus?
Congenital hydrocephalus may cause what symptoms?
Common congenital causes of paediatric hydrocephalus?
Aqueductal stenosis has which mode of inheritance?
X-linked.
Common acquired causes of paediatric hydrocephalus?
What function do valves have in the management of hydrocephalus?
What percentage of valves used in the management of hydrocephalus are no longer functioning after 12 years?
80%.
Complications of shunts used in hydrocephalus?
How may the risk of infection be reduced in the use of shunts in hydrocephalus?
- Iodine +++.