Total CSF space ~150ml or CSF production ~500ml/day or 3-4 turnovers. CSF ab orbed by arachnoid granulations or lymphatic system (lesser)
Types of hydrocephalus
1. Communicating (NPH triad = ataxia or incontinence or dementia). Causes of communicating (blockage of granulations) are subarach or meningitis or leptomingeal mets
2. Noncommunicating - structural lesion (colloid cyst or aqueductal stenosis or Pfossa mass)
3. Obstructive (noncommunicating... unclear how these are different...) 4. Hydrocephalus ex vacuo - ventricular enlargement due to parenchymal volume loss
