Primary Periodic Paralysis (PPP)

Episodes usually appear in later childhood, before a person reaches the age of 20. However, some people begin having episodes as early as age 2 or even younger. Symptoms of weakness during an episode often affect the front of the thighs, hips, upper arms, calves, and shoulders but other areas of the body may also be affected. Episodes can vary in severity and duration. The duration of the episodes can range from minutes to several hours with spontaneous full recovery. Some episodes can last for days, but this is infrequent. Recurrent episodes may lead to slow, progressive loss of muscle function over time.

Misdiagnosis and delays in diagnosis are frequent because symptoms can be confused with other more common conditions, such as emotional issues or cardiovascular disorders. Patients are typically referred to neurologists and neuromuscular specialists for evaluation and treatment.

PPP is generally an inherited disorder; therefore, family history may help with diagnosis. In addition, blood tests (to measure potassium and certain hormone/enzyme levels), muscle tests, and genetic testing (to determine if there is an abnormality in one of the genes associated with PPP) may be performed.

Acute treatment of episodes varies based on the form of PPP. Several medications can be used for episode prophylaxis such as carbonic anhydrase inhibitors to reduce the number, frequency, and severity of episodes. It is also important to monitor and track any triggers felt to be associated with episodes so that these triggers can be avoided to prevent future episodes.