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Headache: A Merck Manual of Patient Symptoms podcast

Intracranial intracranial hypertension causes increased intracranial pressure without a mass lesion or hydrocephalus, probably by obstructing venous drainage; CSF composition is normal.

Idiopathic intracranial hypertension typically occurs in women of childbearing age. Incidence is 1/100,000 in normal-weight women but 20/100,000 in obese women. Intracranial pressure is elevated (> 250 mm H₂O); the cause is unknown but probably involves obstruction of cerebral venous outflow.

Symptoms and Signs

Almost all patients have a daily or near daily generalized headache of fluctuating intensity, at times with nausea. They may also have transient obscuration of vision, diplopia (due to 6th cranial nerve dysfunction), and pulsatile intracranial tinnitus. Vision loss begins peripherally and may not be noticed by patients until late in the course. Permanent vision loss is the most serious consequence.

Bilateral papilledema is common; a few patients have unilateral or no papilledema. In some asymptomatic patients, papilledema is discovered during routine ophthalmoscopic examination. Neurologic examination may detect partial 6th cranial nerve palsy but is otherwise unremarkable.

Diagnosis

• MRI with magnetic resonance venography
• Lumbar puncture

Diagnosis is suspected clinically and established by brain imaging (preferably MRI with magnetic resonance venography) that shows normal results, followed by lumbar puncture showing elevated opening pressure and normal CSF composition. Use of certain drugs and disorders can produce a clinical picture resembling idiopathic intracranial hypertension (see Table 5: Headache: Conditions Associated with Papilledema and Idiopathic Intracranial Hypertension).

Table 5
Conditions Associated with Papilledema and Idiopathic Intracranial Hypertension Condition Examples Obstruction of cerebral venous drainage Cerebral venous sinus thrombosis Jugular vein thrombosis Disorders Addison's disease COPD Hypoparathyroidism Iron deficiency anemia if severe Renal failure Right ventricular heart failure with pulmonary hypertension Sleep apnea Drugs Anabolic steroids Corticosteroid withdrawal after prolonged use Growth hormone in patients with a deficiency Nalidixic acid Some Trade Names NEGGRAM Nitrofurantoin Some Trade Names FURADANTIN MACROBID MACRODANTIN Click for Drug Monograph Tetracycline Some Trade Names ACHROMYCIN V TETRACYN TETREX Click for Drug Monograph and its derivatives Vitamin A toxicity

Treatment

• Acetazolamide Some Trade Names
  DIAMOX
  Click for Drug Monograph
  
• Often weight loss
• NSAIDs or drugs used for migraines

Treatment is aimed at reducing pressure and relieving symptoms. Acetazolamide Some Trade Names
DIAMOX
Click for Drug Monograph
250 mg po qid is used as a diuretic. Obese patients are encouraged to lose weight, which may help reduce intracranial pressure. Serial lumbar punctures are controversial but are sometimes used. Any potential causes (disorders or drugs) are corrected or eliminated if possible. NSAIDs or drugs used for migraine may relieve headache.

If vision deteriorates despite treatment, optic nerve sheath fenestration, shunting (lumboperitoneal or ventriculoperitoneal), or endovascular venous stenting may be indicated. Bariatric surgery with sustained weight loss may cure the disorder in obese patients who were otherwise unable to lose weight.

Frequent ophthalmologic assessment (including quantitative visual fields) is required to monitor response to treatment; testing visual acuity is not sensitive enough to warn of impending vision loss.

Last full review/revision April 2008 by Stephen D. Silberstein, MD

Content last modified April 2008