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Normal pressure hydrocephalus (NPH) is an abnormal build-up of cerebrospinal fluid (CSF) in the brain's ventricles, or cavities. It occurs if the normal flow of CSF throughout the brain and spinal cord is blocked in some way. This causes the ventricles to enlarge, putting pressure on the brain. The unusual features in this type of ventricular enlargement is that the patient does not have the usual symptom of headache which suggests raised pressure and on doing a Lumbar puncture to test pressure, the intracranial pressure is not above the normal pressure range. Hence the term “Normal Pressure Hydrocephalus” or NPH.

  • Most commonly in elderly.
  • Result from a subarachnoid haemorrhage/Head trauma, infection, and in some cases no preceding events to precipitate the problem
  • TRIAD of symptoms
    • Unstable gait
    • Memory Issues
    • Urinary Incontinence.


  1. CT or MRI of the brain – will show prominent ventricles
  2. The diagnostic test is a fissures test.

A lumbar puncture is performed, the starting pressure is noted to be within normal pressure. 30 to 40ml of CSF drained and tests and subjective feedback is assessed to see if the gait/Memory issues/ or bladder incontinence have improved at 48 hours.


In those that have either a subjective or objective improvement, a ventriculo-peritoneal shunt is done. The valve settings can be adjusted so as to be able to lower the pressure to a point at which the patient is clinical improved.

  • royal-australasian-college-of-surgeons
  • flinders-medical-centre
  • cmc-vellore
  • calvary-adelaide-hospital
  • Neurosurgical Research Foundation