Makindo Medical Notes

👩‍⚕️ Idiopathic Intracranial Hypertension (IIH), also called Pseudotumour Cerebri, is a syndrome of raised intracranial pressure without an identifiable structural cause. ⚠️ Though “benign” in name, it is not harmless — untreated, it may cause permanent visual loss from papilloedema.

ℹ️ About

• Most common in young, obese females 📈.
• Mimics a brain tumour clinically and radiologically (hence “pseudotumour”).
• Visual field defects (early blind spot enlargement, inferonasal loss) are characteristic. 👁️

🧬 Aetiology

• Exact cause unknown, but linked to impaired CSF absorption at arachnoid granulations.
• Cerebral venous sinus thrombosis must always be excluded. 🚨

🤝 Associations

• Pregnancy, OCP use, thrombophilia.
• Drugs 💊: Vitamin A/retinoids, tetracyclines (minocycline, doxycycline), growth hormone, nitrofurantoin, danazol, lithium.
• Others: Ketamine, nitrous oxide.

🩺 Clinical Presentation

• Headache: Morning-predominant, worse lying down, eased by ICP reduction.
• Visual: Transient obscurations, blurred vision, papilloedema, visual field loss.
• Other: Diplopia (CN VI palsy), pulsatile tinnitus, neck/back pain.
• Often history of recent weight gain ⚖️ or new medication exposure.

🔬 Investigations

• Bloods: FBC, U&E, LFT, ESR, CRP to exclude systemic causes.
• Visual field testing: Blind spot enlargement, inferonasal defects.
• Imaging: MRI/MRV to exclude mass or venous thrombosis; may show empty sella, enlarged optic nerve sheath.
• LP: Elevated opening pressure (>25 cm H₂O) with normal CSF constituents.

📑 Diagnostic Criteria (Modified Dandy Criteria)

🧾 Differentials

• Cerebral venous sinus thrombosis
• Intracranial mass lesion (tumour, abscess)
• Hydrocephalus

🎯 Management Goals

• Rule out venous sinus thrombosis.
• Preserve vision 👁️.
• Reduce ICP and control headache burden.

💊 Management

• Stop offending drugs (e.g., tetracyclines, retinoids, steroids, nitrofurantoin).
• Weight loss: 5–10% reduction can significantly lower ICP; bariatric surgery may be considered.
• Medical therapy:
  • Acetazolamide (carbonic anhydrase inhibitor) — first-line; reduces CSF production.
  • Topiramate — useful alternative (also promotes weight loss).
  • Loop diuretics (e.g., furosemide) in selected cases.
  • Steroids rarely used — rebound ICP rise on withdrawal.
• Surgical options:
  • Optic nerve sheath fenestration — for threatened vision, rapidly reduces papilloedema.
  • CSF diversion (VP or LP shunt) — in refractory disease.
  • Venous sinus stenting — emerging therapy for stenosis-related IIH.

💡 Exam Pearl

Think “young obese woman with headache + papilloedema + raised LP opening pressure.” 👉 Always exclude venous sinus thrombosis before labelling as IIH. 👉 First-line treatment = weight loss + acetazolamide.

📚 References

• Idiopathic Intracranial Hypertension: Consensus Guidelines
• Papilloedema: Clinical Review (2015)