neurologic disorders
Idiopathic Intracranial Hypertension
Introduction
Idiopathic intracranial hypertension causes increased intracranial pressure without a mass lesion or hydrocephalus, probably by obstructing venous drainage; cerebrospinal fluid composition is normal. (See also Approach to the Patient With Headache .) Idiopathic intracranial hypertension typically occurs in women of childbearing age. Incidence is 1/100,000 in normal-weight women but 20/100,000 in women with obesity. Intracranial pressure (ICP) is elevated (> 250 mm H2O); the cause is unknown but can involve obstruction of cerebral venous outflow, which can result from increased CSF pressure which can result in increased venous obstruction—a vicious circle. In children, this disorder sometimes develops after corticosteroids are stopped or after growth hormone is used. Idiopathic intracranial hypertension may also develop after tetracyclines or large amounts ofvitamin Aare taken. 