CSF and shunt revision

  My daughter wore a subduroperitoneal shunt from 18mos. to 6 yrs. of age for extraaxial fluid collections.  Her development is normal across the board.  Upon a subdural shunt revision it was noted that her CSF opening pressure was 18mg H2O - she had been under anesthesia for approx. 30 minutes.  Her ventricles are within normal limits and she has never shown symptoms of elevated pressure.  Is 18 high considering the circumstances.  Could it have been due to the anesthesia?

[CCF Neuro[P] MD RPS]

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Dear Lynne:
What we usually look at is the head circumference, the neurological exam expecially the fundoscopic exam and optic discs, and make a judgement.  We usually consider 15 or less mm Hg normal, I don't think that 18 would worry me if the other parts of the exam are normal.  It doesn't sound like she has any effects from the very mild increase in pressure.  Something to think about, there is always the chance for operator error.  I don't think the anesthesia would account for the increase in pressure.  I would hope that it was measured correctly.  Anyway, I think I would just follow the neurological exam, and head circumference.  If there are signs of increased ICP such as papilledema, sixth nerve palsy, headache, etc. then I might pursue it.  I think that you should just keep an eye out for things but not chase a 3 mm Hg increase in pressure.
Sincerely,
CCF Neuro[P]MD