• Clinical science

Idiopathic intracranial hypertension (Pseudotumor cerebri…)

Summary

Idiopathic intracranial hypertension (IIH), often referred to as pseudotumor cerebri or benign intracranial hypertension, is a condition of unknown etiology that manifests with chronically elevated intracranial pressure (ICP). It predominantly affects obese women, especially such who have gained significant weight over a short period of time, but certain drugs (growth hormones, tetracyclines, excessive vitamin A) are also associated with the condition. The most common symptoms are diffuse headaches, although various visual symptoms and pulsatile tinnitus are also common. Ophthalmologic examination is crucial for confirming the diagnosis and usually reveals bilateral papilledema and possibly loss of vision. MRI is often done to rule out other causes of increased ICP. Lumbar puncture typically shows an elevated opening pressure. Acetazolamide is the first-line therapy, whereas surgery is only used as a last resort. Even with treatment, the condition often worsens over the course of months to years, and permanent symptoms are common.

Epidemiology

  • Predominantly affects obese women aged 15–44 years [1][2]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

A female TOAD: female sex, Tetracyclines, Obesity, excessive intake of vitamin A, and Danazol are the major risk factors for pseudotumor cerebri.

Classification

Pathophysiology

  • A mismatch between production and resorption of CSF (cause unknown) → ↑ ICP → damage to structures of the CNS and especially to the optical nerve fibers
  • Orthograde axoplasmic flow stasis at the optic nerve head leads to bilateral papilledema.

References:[6]

Clinical features

References:[7]

Diagnostics

The following tests should always be performed: [8][9]

In communicating hydrocephalus (e.g., in IIH), there is no pressure difference between the ventricles and subarachnoid space. Therefore, a decrease in intracranial pressure poses little risk of herniation. Unlike in meningitis, papilledema and other signs of increased intracranial pressure are not a contraindication for LP in IIH.

Treatment

References:[7][9][6]

Prognosis

  • IIH typically worsens over months to years, until the condition stabilizes.
  • Even with treatment, many patients will have persistent symptoms (up to 79%). [13]
  • Severe loss of vision (or even blindness) occurs in up to 24% of patients. [14]
  • 1. Radhakrishnan K, Ahlskog JE, Cross SA, Kurland LT, O'Fallon WM. Idiopathic intracranial hypertension (pseudotumor cerebri). Descriptive epidemiology in Rochester, Minn, 1976 to 1990. Arch Neurol. 1993; 50(1): pp. 78–80. doi: 10.1001/archneur.1993.00540010072020.
  • 2. Kesler A, Gadoth N. Epidemiology of idiopathic intracranial hypertension in Israel. J Neuroophthalmol. 2001; 21(1): pp. 12–4. doi: 10.1097/00041327-200103000-00003.
  • 3. Donahue SP. Recurrence of idiopathic intracranial hypertension after weight loss: the carrot craver. Am J Ophthalmol. 2000; 130(6): pp. 850–1. doi: 10.1016/s0002-9394(00)00607-3.
  • 4. Friedman DI. Medication-induced intracranial hypertension in dermatology. Am J Clin Dermatol. 2005; 6(1): pp. 29–37. doi: 10.2165/00128071-200506010-00004.
  • 5. Wall M. Update on Idiopathic Intracranial Hypertension. Neurol Clin. 2017; 35(1): pp. 45–57. doi: 10.1016/j.ncl.2016.08.004.
  • 6. Biousse V, Bruce BB, Newman NJ. Update on the pathophysiology and management of idiopathic intracranial hypertension. J Neurol Neurosurg Psychiatr. 2012; 83(5): pp. 488–494. doi: 10.1136/jnnp-2011-302029.
  • 7. Jensen RH, Radojicic A, Yri H. The diagnosis and management of idiopathic intracranial hypertension and the associated headache. Ther Adv Neurol Disord. 2016; 9(4): pp. 317–326. doi: 10.1177/1756285616635987.
  • 8. Thurtell MJ, Wall M. Idiopathic intracranial hypertension (pseudotumor cerebri): recognition, treatment, and ongoing management. Curr Treat Options Neurol. 2013; 15(1): pp. 1–12. doi: 10.1007/s11940-012-0207-4.
  • 9. Julayanont P, Karukote A, Ruthirago D, Panikkath D, Panikkath R. Idiopathic intracranial hypertension: ongoing clinical challenges and future prospects. J Pain Res. 2016; 9: pp. 87–99. doi: 10.2147/JPR.S60633.
  • 10. Salman M. Why does tonsillar herniation not occur in idiopathic intracranial hypertension?. Med Hypotheses. 1999; 53(4): pp. 270–271. doi: 10.1054/mehy.1998.0756.
  • 11. Mollan SP, Markey KA, Benzimra JD, et al. A practical approach to, diagnosis, assessment and management of idiopathic intracranial hypertension. Pract Neurol. 2014; 14(6): pp. 380–390. doi: 10.1136/practneurol-2014-000821.
  • 12. Förderreuther S, Straube A. Indomethacin reduces CSF pressure in intracranial hypertension. Neurology. 2000; 55(7): pp. 1043–5. doi: 10.1212/wnl.55.7.1043.
  • 13. Sinclair AJ, Kuruvath S, Sen D, Nightingale PG, Burdon MA, Flint G. Is cerebrospinal fluid shunting in idiopathic intracranial hypertension worthwhile? A 10-year review. Cephalalgia. 2011; 31(16): pp. 1627–33. doi: 10.1177/0333102411423305.
  • 14. Corbett JJ, Savino PJ, Thompson HS, et al. Visual loss in pseudotumor cerebri. Follow-up of 57 patients from five to 41 years and a profile of 14 patients with permanent severe visual loss. Arch Neurol. 1982; 39(8): pp. 461–74. doi: 10.1001/archneur.1982.00510200003001.
last updated 11/25/2020
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