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Elevated Intracranial Pressure (ICP) and Hydrocephalus


  • Communicating hydrocephalus (i.e. non-obstructive)

    • Causes: subarachnoid granule scarring after subarachnoid hemorrhage or meningitis, ependymoma producing excess CSF, venous sinus thrombosis
  • Non-communicating hydrocephalus (i.e. obstructive)

    • Causes: tumor, abscess, or hematoma in the midline ventricular structures
  • Eventually, elevated ICP will cause brain herniation


  • Headache, blurred vision, visual field reduction, enlarged blind spot, nausea, vomiting, syncope, coma

  • Sixth nerve palsies are common

  • Third nerve palsies (blown pupil) are classically associated with uncal herniation


  • Good visual exam: visual fields, enlarged blind spot, papilledema (may not be present if very rapid ICP increase, even with vision loss), and 6th nerve palsies

  • Stat head CT to look for obstructions, mass lesions

    • NSGY evaluation if obstructive lesion (removal vs ventricular drain)
  • CTV or MRV to look for venous sinus thrombosis

    • Venous sinus thrombosis needs AC, even if there is some degree of hemorrhagic infarction
  • If no obstructive lesion LP with opening pressure

    • If workup is otherwise normal, except for elevated opening pressure diagnosis = IIH


  • Idiopathic intracranial hypertension (IIH)

    • Diamox and/or topiramate

    • Ophthalmology evaluation emergently for consideration of nerve sheath fenestrations or urgent VPS placement if severe disc edema

    • If there is clinical concern for herniation:

      • Mannitol: 50g IV, can be given peripherally. Has risks of renal injury

      • Hypertonic saline: 3%, 7% or 23% saline can be given, needs central access

      • Maintain head of bed at least 30° and loosen neck obstructions (c-collars) as able

      • NSGY consult for shunt consideration

    • Hyperventilation can be done with goal PaCO2 30-34 mm Hg or ETCO2 20-30 mmHg but is only a temporizing measure and risks rebound edema

      • After 4-6 hrs, compensatory pH changes in the blood prevent vasoconstrictive affects

Last update: 2022-06-23 16:52:10