(See also Approach to the Patient With Headache Approach to the Patient With Headache Headache is pain in any part of the head, including the scalp, face (including the orbitotemporal area), and interior of the head. Headache is one of the most common reasons patients seek medical... read more .)
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 (ICP) is elevated (> 250 mm H2O); the cause is unknown but probably involves obstruction of cerebral venous outflow, possibly because venous sinuses are smaller than normal.
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 of vitamin A are taken.
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. Once vision is lost, it usually does not return, even if ICP is reduced.
Bilateral papilledema Papilledema Papilledema is swelling of the optic disk due to increased intracranial pressure. Optic disk swelling resulting from causes that do not involve increased intracranial pressure (eg, malignant... read more 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 Sixth Cranial (Abducens) Nerve Palsy Sixth cranial nerve palsy affects the lateral rectus muscle, impairing eye abduction. The eye may be slightly adducted when the patient looks straight ahead. The palsy may be secondary to nerve... read more but is otherwise unremarkable.
Pearls & Pitfalls
MRI with magnetic resonance venography
If clinical findings suggest idiopathic intracranial hypertension, clinicians should check visual fields and optic fundi, even in patients with no visual symptoms.
Diagnosis of idiopathic intracranial hypertension is suspected clinically and established by brain imaging (preferably MRI with magnetic resonance venography) that has normal results (except for narrowing of the venous transverse sinus). If not contraindicated, lumbar puncture with cerebrospinal fluid (CSF) testing is then done. Elevated opening pressure and normal CSF composition suggests idiopathic intracranial hypertension.
Use of certain drugs and certain disorders can produce a clinical picture resembling idiopathic intracranial hypertension and should be excluded (see table Conditions Associated With Papilledema and Resembling Idiopathic Intracranial Hypertension Conditions Associated With Papilledema and Resembling Idiopathic Intracranial Hypertension ).
Acetazolamide or topiramate
Weight loss if needed
Drugs used for migraine, especially topiramate
Idiopathic intracranial hypertension occasionally resolves without treatment.
Treatment of idiopathic intracranial hypertension is aimed at the following:
The carbonic anhydrase inhibitor acetazolamide (250 mg orally 4 times a day) or topiramate (which also inhibits carbonic anhydrase) up to 200 mg twice a day is used. Acetazolamide reduces cerebrospinal fluid production. Topiramate can help patients lose weight, help lower intracranial pressure, and may relieve headache.
Obese patients are encouraged to lose weight, which may help reduce intracranial pressure.
Serial lumbar punctures are controversial but are sometimes used, particularly if, while waiting for definitive treatment, vision is threatened. (Definitive treatment includes optic nerve sheath fenestration, shunting, and venous sinus stenting.)
Any potential causes (disorders or drugs) are corrected or eliminated if possible.
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.
If vision deteriorates despite treatment, one of the following may be indicated:
Optic nerve sheath fenestration
Shunting (lumboperitoneal or ventriculoperitoneal)
Endovascular venous stenting
Bariatric surgery Bariatric Surgery Bariatric surgery is the surgical alteration of the stomach, intestine, or both to cause weight loss. In the US, about 250,000 bariatric operations are done in each year. Development of safer... read more with sustained weight loss may cure the disorder in obese patients who were otherwise unable to lose weight.
Consider idiopathic intracranial hypertension if patients, particularly overweight women, have a daily generalized headache with or without visual symptoms; check visual fields and optic fundi.
Diagnose based on results of brain imaging (preferably MRI with venography) and, if not contraindicated, lumbar puncture.
Advise weight loss if needed, and treat with acetazolamide or topiramate.
Do frequent ophthalmologic assessments (including quantitative visual fields) to monitor response to treatment.
If vision deteriorates despite treatment, consider optic nerve sheath fenestration, shunting, or endovascular venous stenting.