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pseudotumor cerebri; idiopathic intracranial hypertension

A disorder simulating the presence of an intracranial tumor. Etiology: 1) impaired absorption of CSF by arachnoid villi 2) dural sinus thrombosis 3) mastoiditis 4) Behcet disease 5) renal failure 6) obstructive sleep apnea 7) pharmacologic causes: a) amiodarone b) glucocorticoid withdrawal c) mineralocorticoids d) oral contraceptives e) levonorgestrel subdermal implant e) tetracyclines f) systemic retinoids, vitamin A (hypervitaminosis A) g) growth hormone 8) obesity is risk factor Epidemiology: - commonly associated with obesity in young females - may occur during pregnancy or in the peripartum Pathology: 1) cerebral edema (papilledema) 2) small cerebral ventricles 3) increased intracranial pressure Clinical manifestations: 1) papilledema may be observed on funduscopy - often asymmetric, rarely unilateral 2) headache (> 90%) 3) pulsatile tinnitus (60%) 4) transient visual disturbances a) photophobia b) blurred vision c) diplopia d) visual field loss 5) neck pain in common 6) ophthalmoplegia - cranial nerve 6 palsy is a false localizing sign associated with intracranial hypertension 7) obesity common Special laboratory: - lumbar puncture (elevated opening pressure) > 250 mm Hg - CSF examination is normal - slit lamp examination Radiology: - contrast-enhanced brain MRI may show - widening of optic nerve sheaths - partially empty sella - flattening of the posterior optic globes [4] - small ventricles - magnetic resonance venography to exclude dural sinus venous thrombosis [4] Management: 1) consult neurology & ophthalmology 2) goals: preserve vision, alleviate symptoms 3) carbonic anhydrase inhibitor (acetazolamide, topiramate) [4] 4) avoid glucocorticoids due to weight gain & fluid retention 5) if medical management fails & visual changes are progressive a) optic nerve sheath fenestration b) lumboperitoneal shunting has high rate of failure [4] 6) long-term - weight reduction

General

pseudotumor increased intracranial pressure (ICP)

References

  1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39
  2. Stedman's Medical Dictionary 26th ed, Williams & Wilkins, Baltimore, 1995
  3. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 72, 167
  4. Medical Knowledge Self Assessment Program (MKSAP) 15,16,17,18,19. American College of Physicians, Philadelphia 2009,2012,2015,2018,2021 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  5. Wall M. Idiopathic intracranial hypertension. Neurol Clin. 2010 Aug;28(3):593-617 PMID: 20637991
  6. Markey KA, Mollan SP, Jensen RH, Sinclair AJ. Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions. Lancet Neurol. 2016 Jan;15(1):78-91. Review. PMID: 26700907