Pseudotumor cerebri

Definition

Pseudotumor cerebri is a chronic elevation of intracranial pressure that causes papilloedema and possibly blindness, which occurs in the absence of a mass lesion in the brain.

Description

Pseudotumor cerebri primarily affects obese women of childbearing age, and its cause is not known. The disorder is possibly the result of an abnormality in venous blood outflow from the brain, or from an abnormality in cerebrospinal fluid (CSF) flow. The increase in intracranial pressure can result in headache , visual impairment, pain , and hearing problems.

Demographics

Three significant studies concerning pseudotumor cerebri have been conducted in Iowa and Louisiana, the Mayo Clinic in Rochester, Minnesota, and Benghazi, Libya. The incidence of pseudotumor cerebri increases in women between 14 and 44 years of age, who are obese. In the Iowa and Louisiana study, the incidence was 19.3 per 100,000 in women who were 20% over ideal weight. In the Mayo Clinic study, the annual incidence number of new cases between 1976 and 1990 was found to be approximately eight per 100,000 for obese women 15–44 years old. In the Benghazi study (from 1982–1989), the annual incidence was 21 per 100,000 obese women 15–44 years old. No evidence of any racial or ethnic predilection exists.

Causes and symptoms

The cause of pseudotumor cerebri is unknown, but it is thought to result from a faulty mechanism in CSF or venous flow from the brain. Certain risk factors have been associated with the disorder that include female gender, menstrual irregularity, obesity, recent weight gain, endocrine (hormone) disorders such as hypothyroidism (underactive thyroid disorder), or medication taken such as cimetidine (anti-ulcer), corticosteroids, lithium (used to treat bipolar disorder), tetracycline, sulfa antibiotics, recombinant human growth hormone, oral contraceptives, and vitamin A intake in infants.

Patients can have symptoms such as headache, ringing sounds in the ears, double vision (diplopia), or pain in the arms. Additionally, patients may have back pain , neck pain, or stiffness and arthralgias in the shoulder, knee, and wrist. Patients usually develop papilloedema, which can causes visual obscurations (dimming), progressive loss of peripheral vision, blurring, and sudden visual loss (resulting from intraocular hemorrhage).

Diagnosis

Neuroimaging studies are the best diagnostic tools, especially brain magnetic resonance imaging (MRI) scans. MRI scans provide good images that can reveal other possible disease states that cause increased intracranial pressure. General and special blood tests are typically ordered. CSF studies are also indicated and are usually done by inserting a needle into the lumbar region of the spine to withdraw a fluid sample. CSF studies are done to detect an infection within the central nervous system ; the sample is used for tumor tests.

Treatment team

Management of pseudotumor cerebri requires a lumbar puncture that is performed by a neurologist or

internist. Visual problems may be monitored by a neuroophthalmologist. Neurosurgical consultations are necessary if treatment does not arrest or reverse the condition quickly, within hours to days.

Treatment

Patients who do not develop visual loss are often treated with a drug called acetazolamide (a carbonic anhydrase inhibitor) that lowers intracranial pressure. In persons who present with more severe symptoms such as early loss of vision, a short treatment course with high-dose corticosteroids (prednisone) is recommended. Tapering down from the initial corticosteroid dose is individualized and based on the improvement of symptoms. If new visual loss is noted despite treatment, emergency surgical intervention may be indicated. A procedure called a lumboperitoneal shunt is the method of choice utilized for prompt reduction of intracranial hypertension; this is a surgical redirection of fluid flow in the brain, which creates an outflow of fluid from the brain that decreases intracranial pressure.

Recovery and rehabilitation

A formal weight loss and exercise program is required once the diagnosis is established. Admission to the hospital is uncommon, but some patients may be admitted for a short stay for intravenous fluid hydration and pain management in cases of intractable headache. Admission to the hospital is also indicated if the patient is a surgical candidate due to severe visual loss. Patients require education concerning blindness and weight reduction. Programs designed to lose weight should include an exercise program and psychological consultations. Many patients do not successfully lose enough weight and may require drastic treatment approaches such as gastric resection or stapling.

Clinical trials

The National Institute of Health is conducting a trial concerning the role of thrombosis inside blood vessels and the development of pseudotumor cerebri.

Prognosis

Typically, persons affected with pseudotumor cerebri can develop blindness, which is the only severe and permanent complication of this disorder. The blindness, which progressively worsens, is due to papilloedema.

Special concerns

Diligent treatment is required since eye deficits in one or both eyes can have a very quick onset and can be disabling. The disorder is not statistically correlated with weight gain during pregnancy; however, both pregnancy and pseudotumor cerebri are linked to weight gain and female gender (within childbearing age).

Resources

BOOKS

Marx, John A., et al (eds). Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed. St. Louis: Mosby, Inc., 2002.

Noble, John., et al (eds). Textbook of Primary Care Medicine, 3rd ed. St. Louis: Mosby, Inc., 2001.

WEBSITES

Health Topics A-Z. (May 23, 2004.) <http://www.medhelp.org>.

ORGANIZATIONS

Pseudotumor Cerebri Support Network. 8247 Riverside Drive, Powell, OH 43065. (614) 895-8814. <http://www.pseudotumorcerebri.com>.

Laith Farid Gulli, MD

Robert Ramirez, DO

Nicole Mallory, MS, PA-C