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NINDS Familial Periodic Paralyses Information Page

Synonym(s):   Periodic Paralyses

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What are Familial Periodic Paralyses?

Familial periodic paralyses are a group of inherited neurological disorders caused by mutations in genes that regulate sodium and calcium channels in nerve cells. They are characterized by episodes in which the affected muscles become slack, weak, and unable to contract. Between attacks, the affected muscles usually work as normal.

The two most common types of periodic paralyses are:
Hypokalemic periodic paralysis is characterized by a fall in potassium levels in the blood. In individuals with this mutation attacks often begin in adolescence and are triggered by strenuous exercise, high carbohydrate meals, or by injection of insulin, glucose, or epinephrine. Weakness may be mild and limited to certain muscle groups, or more severe and affect the arms and legs. Attacks may last for a few hours or persist for several days. Some patients may develop chronic muscle weakness later in life.
Hyperkalemic periodic paralysis is characterized by a rise in potassium levels in the blood. Attacks often begin in infancy or early childhood and are precipitated by rest after exercise or by fasting. Attacks are usually shorter, more frequent, and less severe than the hypokalemic form. Muscle spasms are common.

Is there any treatment?

Treatment of the periodic paralyses focuses on preventing further attacks and relieving acute symptoms. Avoiding carbohydrate-rich meals and strenuous exercise, and taking acetazolamide daily may prevent hypokalemic attacks. Attacks can be managed by drinking a potassium chloride oral solution. Eating carbohydrate-rich, low-potassium foods, and avoiding strenuous exercise and fasting, can help prevent hyperkalemic attacks. Dichorphenamide may prevent attacks.

What is the prognosis?

The prognosis for the familial periodic paralyses varies. Chronic attacks may result in progressive weakness that persists between attacks. Some cases respond well to treatment, which can prevent or reverse progressive muscle weakness

What research is being done?

The NINDS conducts and supports research on neuromuscular disorders such as the familial periodic paralyses. These studies are aimed at increasing knowledge about these disorders and finding ways to prevent, treat, and cure them.

NIH Patient Recruitment for Familial Periodic Paralyses Clinical Trials

Organizations

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Muscular Dystrophy Association
3300 East Sunrise Drive
Tucson, AZ   85718-3208
mda@mdausa.org
http://www.mda.org
Tel: 520-529-2000 800-572-1717
Fax: 520-529-5300

National Organization for Rare Disorders (NORD)
55 Kenosia Avenue
Danbury, CT   06810
orphan@rarediseases.org
http://www.rarediseases.org
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
Fax: 203-798-2291

Related NINDS Publications and Information


Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892



NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.

All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.

Last updated March 12, 2012