Hypokalemic periodic paralysis

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Periodic paralysis - hypokalemic

• Weakness or paralysis
  • Most commonly located at the shoulders and hips
  • Involves the arms and legs
  • Occurs intermittently
  • Most commonly occurs on awakening
  • May be triggered by rest after exercise
  • May be triggered by heavy, high-carbohydrate, high-salt meals or alcohol consumption
  • Usually lasts less than 24 hours
• Normal muscle strength between attacks
• Positive Babinski's reflex
• Eyelid spasms between episodes

The health care provider may suspect hypokalemic periodic paralysis if the symptoms come and go, potassium levels are low during attacks, and other disorders known to cause low potassium are not suspected. Hypokalemic periodic paralysis is also likely if other family members have the disorder.

Between attacks, a physical examination shows nothing abnormal. Before an attack there may be leg stiffness or heaviness in the legs. Performing mild exercise when these symptoms start may help prevent a full blown attack.

During an attack, muscle reflexes may be decreased or absent and muscles go limp rather than staying stiff. The muscle groups near the body, such as shoulders and hips are involved more often than the arms and legs.

• Serum potassium is low during attacks but normal between attacks (confirming the diagnosis of hypokalemic periodic paralysis).
• An ECG or heart tracing may be abnormal during attacks.
• An EMG or muscle tracing is usually normal between attacks and abnormal during attacks.
• A muscle biopsy may show abnormalities.

Review Date: 07/25/2006
Reviewed By: David M. Charytan, M.D., M.Sc., Department of Medicine, Division of Nephrology, Brigham and Women's Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.