CSF Pathology Flashcards
What is the mean CSF pressure?
- 10mmHg.
- 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?
- Choroid pelxus (75%).
- 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?
- Buoyancy (reduces brain weight by 96% - 1500g to 60g).
- Accommodation of physiological changes in vascular volumes in the head (- displaced into spinal canal).
Chemical functions of CSF?
- Provides micronutrients to cerebral tissue (e.g. Vitamin C, thyroxine).
- Clears some waste products of nerve cell metabolism e.g. 5HIAA.
- Ionic homeostasis.
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.
- Cerebral oedema.
- Benign intracranial hypertension.
- Spinal dural arteriovenous fistula.
- Syringomyelia and cord oedema.
Classification of hydrocephalus?
- Obstructive.
- Communicating.
- Infantile.
- Childhood/adult.
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?
- Unusually large ehad.
- Thin and shiny scalp with easily visible veins.
- Bulging or tense fontanelle.
- Downward looking eyes.
Congenital hydrocephalus may cause what symptoms?
- Poor feeding.
- Irritability.
- Vomiting.
- Sleepiness.
- Muscle stiffness and spasms in a baby’s lower limbs.
Common congenital causes of paediatric hydrocephalus?
- Chiari malformation or Spina Bifida.
- Aqueductal stenosis.
- Dandy Walker complex.
- Congenital arachnoid cysts.
- Atresia of foramen of Munro.
Aqueductal stenosis has which mode of inheritance?
X-linked.
Common acquired causes of paediatric hydrocephalus?
- Haemorrhage (IHV - intraventricular haemorrhage).
- Infection (post-meningitis).
- Traumatic head injury.
- Tumour.
What function do valves have in the management of hydrocephalus?
- Fixed differential pressure.
- Adjustable.
- Anti-syphon.
- Switch able.
- Constant flow.
What percentage of valves used in the management of hydrocephalus are no longer functioning after 12 years?
80%.
Complications of shunts used in hydrocephalus?
- Overdrainage.
- Underdrainage.
- Infection.
How may the risk of infection be reduced in the use of shunts in hydrocephalus?
- Antibiotics or silver impregnated shunts.
- Iodine +++.