• Clinical science

Idiopathic intracranial hypertension (Pseudotumor cerebri…)

Abstract

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 weight, 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 15–45 years

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[1]

Pathophysiology

A mismatch between production and resorption of CSF (cause unkown) → ↑ ICP → damage to structures of the CNS and especially to the optical nerve fibers

References:[2]

Clinical features

References:[3][4]

Diagnostics

The following tests should always be performed

  • Ophthalmologic examination
    • Opthalmoscopy: bilateral papilledema
    • Visual field test may show peripheral loss of vision
  • MRI
  • Lumbar puncture
    • Elevated opening pressure >20–25 cm H2O (with patient lying on the side, legs extended)
    • Normal CSF analysis with no signs of inflammation or bleeding

References:[5][6][7]#4911][8]

Treatment

  • Discontinue any offending agents
  • Weight loss
  • Medical therapy (first line)
  • Surgery: if conservative measures fail
    • Optic nerve sheath fenestration
    • CSF shunt

References:[1][3][7][9][2]

Prognosis

  • Typically worsens over months to years, until the condition stabilizes
  • Even with treatment, many patients will have persistent symptoms (up to 60%)
  • Severe loss of vision (or even blindness) occurs in up to 14% of patients

References:[9]