Pseudotumor Cerebri

Abstract

Pseudotumor cerebri is a relatively common cause of headache. It has an incidence of 2.2 per 100,000 patients, approximately the same incidence as cluster headache. Also known as idiopathic intracranial hypertension, pseudotumor cerebri is seen most frequently in overweight women between the ages of 20 and 45 years. An increased incidence of pseudotumor cerebri is also associated with pregnancy. The exact cause of pseudotumor cerebri has not been elucidated, but the common denominator appears to be a defect in the absorption of cerebrospinal fluid (CSF). Predisposing factors include ingestion of various medications including tetracycline, vitamin A, corticosteroids, and nalidixic acid. Other implicating factors include blood dyscrasias, anemias, endocrinopathies, and chronic respiratory insufficiency. In many patients, however, the exact cause of pseudotumor cerebri remains unknown.

Keywords

pseudotumor cerebri, obesity, vitamin A, tetracycline, nalidixic acid, headache, Valsalva maneuver, papilledema, lumbar puncture

ICD-10 CODE G93.2

The Clinical Syndrome

An often missed diagnosis, pseudotumor cerebri is a relatively common cause of headache. It has an incidence of 2.2 per 100,000 patients, approximately the same incidence as cluster headache. Also known as idiopathic intracranial hypertension, pseudotumor cerebri is seen most frequently in overweight women between the ages of 20 and 45 years. If epidemiologic studies look only at obese women, the incidence increases to approximately 20 cases per 100,000 patients. An increased incidence of pseudotumor cerebri is also associated with pregnancy. The exact cause of pseudotumor cerebri has not been elucidated, but the common denominator appears to be a defect in the absorption of cerebrospinal fluid (CSF). Predisposing factors include ingestion of various medications including tetracycline, vitamin A, corticosteroids, and nalidixic acid ( Box 8.1 ). Other implicating factors include blood dyscrasias, anemias, endocrinopathies, and chronic respiratory insufficiency. In many patients, however, the exact cause of pseudotumor cerebri remains unknown.

Box 8.1

Medications Reportedly Associated With Intracranial Hypertension

Vitamins

Vitamin A
Retinol
Retinoids

Antibiotics

Tetracycline and derivatives
Nalidixic acid
Nitrofurantoin
Penicillin

Protein Kinase C Inhibitors

Lithium carbonate

Histamine (H ₂)-Receptor Antagonists

Cimetidine

Steroids

Corticosteroid withdrawal
Levonorgestrel
Danazol
Leuprolide acetate
Tamoxifen
Growth hormone
Oxytocin
Anabolic steroids

Nonsteroidal Antiinflammatory Drugs

Ketoprofen
Indomethacin
Rofecoxib

Antiarrhythmics

Amiodarone

Anticonvulsants

Phenytoin

Dopamine Precursors

Levodopa
Carbidopa

Signs and Symptoms

More than 90% of patients suffering from pseudotumor cerebri present with the complaint of headache, are female, and have headaches that increase with the Valsalva maneuver. Associated nonspecific central nervous system signs and symptoms, such as dizziness, visual disturbance including diplopia, tinnitus, photophobia, nausea and vomiting, and ocular pain can often obfuscate what should otherwise be a reasonably straightforward diagnosis, given that basically all patients suffering from pseudotumor cerebri (1) have papilledema on fundoscopic examination ( Fig. 8.1 ), (2) are female, and (3) are obese. The extent of papilledema varies from patient to patient and may be associated with subtle visual field defects including an enlarged blind spot and inferior nasal visual field defects ( Fig. 8.2 ). If the condition is untreated, blindness may result ( Fig. 8.3 ).