Idiopathic Intracranial Hypertension (IIH)

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Clinical Presentation

  • Pseudotumor cerebri
  • Bilateral papilledema (acute stage: optic nerve head swelling 1 2, chronic: optic atrophy )
  • Loss of spontaneous venous pulse (absent in 20% of normal population)
  • Transient visual obscurations
  • +/- diplopia (due to sixth nerve palsy)
  • Enlarged blind spot in visual field examination or arcuate scotomas; other defects possible, concentric visual field restriction suggests optic nerve damage
  • Headaches, typically occipital and positional (worsens when lying down)
  • Nausea, vomiting
  • Pulsatile tinnitus

Work-up

  • Emergency CT angiography of the head to rule out a venous sinus thrombosis
    • MRI angiography with venography within 1 week if no acute symptoms
  • Blood pressure (malignant hypertension?)
  • Laboratory tests: TSH, fT3, fT4, electrolytes, creatinine, vitamin A, B12, albumin, ASAT, ALAT, iron status (to rule out secondary causes of pseudotumor cerebri) + INR (for lumbar puncture)
  • Further history:
    • Medication intake: steroids, oral contraceptives, vitamin A, tetracyclines, nalidixic acid, lithium, isotretinoin
    • Personal history: COPD, pregnancy, neck surgery, weight gain?
    • In women: regular menstruation? (indications of PCOS?)
  • Follow-up (within 1-2 weeks):
    • Goldman visual field, OCT
    • MRI of the head (if not already done initially) to rule out small mass lesions
    • Lumbar puncture AFTER MRI
      • Elevated opening pressure >25 cm H2O in lying position, normal cerebrospinal fluid composition

Management

  • Diamox (acetazolamide) therapy for about 1 year, consider tapering off earlier if only mild papilledema and successful rapid weight loss
    • Start with 2x 250mg/day in the first week, then 4x 250mg/day (+ potassium effervescent tablets 30mmol/day)
    • First follow-up after 1 month -> Diamox can be increased to max. 2g daily if insufficient response (initial monthly potassium checks, then every 3 months)
    • Tapering off: relatively quickly over a few weeks, after stopping Diamox therapy, follow-ups initially every 6-12 weeks
  • Topiramate therapy (alternative, if Diamox is not tolerated or if mainly headaches are present -> also a migraine medication)
    • Start with 25mg in the evening, increase by 25mg/day each week to 2x50mg/day (up to a maximum of 200-250mg daily). Potassium supplementation needed from 100mg/day, similar to Diamox therapy.
  • Gradually increase Topiramate to 2x 50mg:
    • Start with 25mg in the evening, then increase by 25mg/day each week
    • Dose can be increased up to 200-250mg daily
    • From 100mg daily, potassium supplementation is necessary, similar to Diamox therapy
    • Mandatory reliable contraception and adequate fluid intake, especially during exercise
    • Regular laboratory or medication checks are not mandatory
    • Alternatively, Furosemide (Lasix), initial kidney function check recommended
  • Weight loss: target 10-15% reduction, nutritional counselling
  • If advanced visual field defects or pregnancy (Diamox and Topiramate contraindicated)
    • Evaluate optic nerve sheath fenestration or lumbo-peritoneal shunt placement
  • If sinus stenoses and non-response to medication:
    • Refer patient to neuroradiology for transstenotic pressure gradient measurement and assessment of the need for sinus stenting

Sources