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7.1.1Headache attributed to idiopathic intracranial hypertension (IIH) [G93.2] G44.820  
Previously used terms Benign intracranial hypertension (BIH), pseudotumor cerebri, meningeal hydrops, serous meningitis

Diagnostic criteria:

  1. Progressive headache with at least one of the following characteristics and fulfilling criteria C and D:
    1. daily occurrence
    2. diffuse and/or constant (non-pulsating) pain
    3. aggravated by coughing or straining
  2. Intracranial hypertension fulfilling the following criteria:
    1. alert patient with neurological examination that either is normal or demonstrates any of the following abnormalities:
      1. papilloedema
      2. enlarged blind spot
      3. visual field defect (progressive if untreated)
      4. sixth nerve palsy
    2. increased CSF pressure (>200 mm H2O in the non-obese, >250 mm H2O in the obese) measured by lumbar puncture in the recumbent position or by epidural or intraventricular pressure monitoring
    3. normal CSF chemistry (low CSF protein is acceptable) and cellularity
    4. intracranial diseases (including venous sinus thrombosis) ruled out by appropriate investigations
    5. no metabolic, toxic or hormonal cause of intracranial hypertension
  3. Headache develops in close temporal relation to increased intracranial pressure
  4. Headache improves after withdrawal of CSF to reduce pressure to 120-170 mm H2O and resolves within 72 hours of persistent normalisation of intracranial pressure


IIH most commonly occurs in young obese women.

Although the majority of patients with IIH have papilloedema, IIH without papilloedema is observed. Other symptoms or signs of IIH include intracranial noises, tinnitus, transient visual obscurations and diplopia.