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General Information ⬇

Definition

A syndrome in which patients present with symptoms and signs of elevated intracranial pressure, the nature of which may be either idiopathic or due to various causative factors.

Symptoms ⬆ ⬇

Headache, transient episodes of visual loss (typically lasting seconds) often precipitated by changes in posture, double vision, pulsatile tinnitus, nausea, or vomiting accompanying the headache. Occurs predominantly in obese women.

Signs ⬆ ⬇

Critical

By definition, the following findings are present:

  • Papilledema due to increased intracranial pressure.
  • Negative MRI/MRV of the brain.
  • Increased opening pressure on LP with normal CSF composition.

Other

See 10.15, PAPILLEDEMA. Unilateral or bilateral sixth cranial nerve palsy may be present. There are no other neurologic signs on examination aside from possible sixth cranial nerve palsy.

Differential Diagnosis ⬆ ⬇

See 10.15, PAPILLEDEMA.

Associated Factors

Obesity, significant weight gain, and pregnancy are often associated with the idiopathic form. Possible causative factors include various medications such as oral contraceptives, tetracyclines (including semisynthetic derivatives, e.g., doxycycline), cyclosporine, vitamin A (>100,000 U/d), amiodarone, sulfa antibiotics, lithium, and historically nalidixic acid (now rarely used). Systemic steroid intake and withdrawal may also be causative.

Work Up ⬆ ⬇

Workup
  1. History: Inquire specifically about medications.
  2. Ocular examination, including pupillary examination, ocular motility, assessment for dyschromatopsia (e.g., color plates), and optic nerve evaluation.
  3. Systemic examination, including blood pressure and temperature.
  4. MRI/MRV of the orbit and brain. Any patient with papilledema needs to be imaged immediately. If normal, the patient should have an LP, to rule out other causes of optic nerve edema and to determine the opening pressure (see 10.15, PAPILLEDEMA).
  5. Visual field test is the most important method for following these patients (e.g., Humphrey).

Treatment ⬆ ⬇

Idiopathic intracranial hypertension may be a self-limited process. Treatment is indicated in the following situations:

  • Severe, intractable headache.
  • Evidence of progressive decrease in visual acuity or visual field loss.
  • Some ophthalmologists suggest treating all patients with papilledema.

Methods of treatment include the following:

  1. Weight loss if overweight.
  2. Acetazolamide 250 mg p.o. q.i.d. initially, building up to 500 to 1000 mg q.i.d. if tolerated. Use with caution in sulfa-allergic patients.
  3. Discontinuation of any causative medication.
  4. Consider short course of systemic steroids, especially if any plans for surgical intervention.

If treatment by these methods is unsuccessful, consider a surgical intervention:

  1. A neurosurgical shunt (ventriculoperitoneal or lumboperitoneal) or venous sinus stenting procedure should be considered if intractable headache is a prominent symptom.
  2. Optic nerve sheath decompression surgery or neurosurgical shunt (ventriculoperitoneal or lumboperitoneal) is often effective if vision is threatened.

Special Circumstances

  1. Pregnancy: Incidence of idiopathic intracranial hypertension does not increase during pregnancy beyond what would be expected from the weight gain. No increased risk of fetal loss. Acetazolamide may be used after 20 weeks of gestation (in consultation with OB/GYN). Intense weight loss is contraindicated during pregnancy. Without visual compromise, close observation with serial visual fields is recommended. With visual compromise, consider steroids, optic nerve sheath decompression, shunting, or repeat LPs.
  2. Children/adolescents: A secondary cause is identifiable in 50% patients.

Follow Up ⬆

  1. If acute, patients can be monitored every 3 months in the absence of visual field loss. If chronic, initially follow patient every 3 to 4 weeks to monitor visual acuity and visual fields and then every 3 months depending on the response to treatment.
  2. In general, the frequency of follow up depends on the severity of visual loss. The more severe, the more frequent the follow up.