CSF Circulation Flashcards
Differences between composition of CSF and blood?
Few cells
Less protein
Reduced concentration of potassium and calcium ions
Higher concentration of magnesium and chloride ions
Volume and flow rate of CSF?
Volume - 150ml
Flow rate - approx 500ml/day
Hydrocephalus types? (2)
Communicating - all 4 ventricles enlarged
Non-communicating - not all ventricles enlarged
Causes of communicating hydrocephalus?
Block in CSF absorption or CSF flow over brain surface Meningitis Head injury Congenital Sub-arachnoid haemorrhage
Causes of non-communicating hydrocephalus?
Block in ventricular system
Aqueduct stenosis
Ventricular tumours
Paraventricular tumours
Signs and symptoms of hydrocephalus?
Headache Drowsiness Blackouts Raised intracranial pressure Increased head circumference (in child)
Treatment of hydrocephalus?
Remove cause (e.g. tumour) Divert CSF (e.g. shunt) Open alternate pathway (e.g. ventriculostomy)
Causes of epidural/extradural and subdural haemorrhages?
Epidural - Damaged meningeal artery between skull and dura after head trauma
Subdural - Damaged vein between dura and arachnoid membrane
How do you distinguish between the two types of haemorrhage?
First symptoms are likely to arise promptly after arterial bleeding (epidural) while they may be delayed by hours/days after venous bleeding (subdural)
The 2 structures affected in meningitis?
Arachnoid membrane
Pia mater
The 2 types of meningitis?
Bacterial
Viral
What is used to distinguish between bacterial and viral meningitis?
CSF analysis
CSF analysis and features of bacterial meningitis?
High white cell count with neutrophils predominating
Increased protein concentration
Decreased glucose concentration
Bacteria may be identifiable - cloudy CSF
CSF analysis and features of viral meningitis?
Any increase in white cells is predominantly lymphocytes
Protein and glucose level in CSF are normal
Viral identification is unlikely
