Disease Information for Pseudotumor cerebri/Benign Intracranial Hypertension: Definition

  • Idiopathic Intracranial Hypertension; Idiopathic intracranial hypertension (I I H) is also known as pseudotumor cerebri or benign intracranial hypertension; The term idiopathic intracranial hypertension, however, is preferred because this is not always a benign disorder and may have significant neurologic sequelae in affected

    individuals; IIH is a relatively common neurologic disease seen primarily in young obese women of childbearing age; Several predisposing factors have been

    identified, including the use of oral contraceptives, anabolic steroids, tetracyclines, and vitamin A; The pathophysiology of this disease remains controversial, with increased brain water content and decreased CSF outflow considered the two major causative factors; The most prominent symptom is generalized headache, which is often gradual in onset and of moderate intensity; There

    is no specific localizing pattern, though in some patients, it is worsened by eye movement; It may awaken patients from sleep and is exacerbated by bending forward or the Valsalva maneuver, which impede cerebral venous return; AM headache occurs; Visual complaints are common and patients may experience transient visual obscuration several times a day secondary to ischemia of the visual pathways These episodes can be followed by prolonged periods of visual

    loss, which can become permanent in up to 10% of patients; papilledema and visual field efects, including an enlarged blind spot initially followed by loss of peripheral vision; Occasionally, a sixth nerve palsy ; Diagnosis should not be made without neuroimaging and measurement on LP of opening pressure or Intracranial Pressure [ ICP >200 mm H2 O]; Signs [papilledema] and symptoms of increased ICP with absence of localizing signs AND No mass lesions or ventricular enlargement on neuroimaging; Normal or low CSF protein and normal cell count; No clinical or neuroimaging suspicion of venous sinus thrombosis; Treatment; lowering ICP and managing the headache; Acetazolamide (a carbonic anhydrase inhibitor) can be used to decrease CSF production [alone or with a loop diuretic such as furosemide] Steroids also have been used, although their mechanism of action is unclear; Prolonged therapy is problematic, and rebound IIH often occurs when doses are tapered; Repeated lumbar punctures can be attempted but most patients find this approach objectionable; In patients with impending visual loss or incapacitating symptoms, a ventricular shunt or optic nerve sheath fenestration may be indicated;[Adapted from Rosen Emergency Medicine 2004