Periodic paralysis is a rare inherited condition that causes occasional episodes of severe muscle weakness. The two most common types of periodic paralysis are
Periodic paralysis is a congenital condition, meaning it is present from birth. Familial periodic paralysis is inherited, but may occur without a known family history. Periodic paralysis is caused by abnormalities of the electrolyte channels on muscles.
The inherited form of the disorder is autosomal dominant, which means that only one affected parent is needed to transmit the gene to the baby. When one parent is affected, the child has a 50% chance of getting the disease. Rarely, the condition occurs as a result of a noninherited genetic defect.
These factors increase your chance of developing periodic paralysis. Tell your doctor if you have any of these risk factors:
Family history of periodic paralysis
Thyroid disorder (particularly in Asian males)
While muscle strength returns to normal between attacks, repeated bouts of weakness may lead to chronic muscle weakness later in life. The person remains alert and aware during attacks, and there is no accompanying loss of sensation.
Episodic bouts of severe weakness in the arms and legs are the most prominent symptom. Typically these bouts occur during sleep, especially after strenuous activity. Cold, stress, and alcohol may also produce attacks. Other, less common, symptoms may include:
Difficulty breathing or swallowing—This requires emergency care.
Some features are specific to the type of periodic paralysis.
are low during attacks
Frequency of attacks varies from daily to yearly
Attacks usually last between 4-24 hours, but can last for several days
Attacks usually begin in adolescence, but they can occur before age 10
Potassium levels are high or normal during attacks
Attacks are usually shorter (lasting 1-2 hours), more frequent , and less severe than the hypokalemic form; breathing and swallowing difficulties are extremely rare
Between attacks, patients often experience muscle spasms or difficulty relaxing their muscles, a condition known as myotonia
Attacks usually begin in early childhood
Persons with some types of periodic paralysis are at risk for a condition known as malignant hyperthermia. This can occur during the use of
. Anyone with a family history of periodic paralysis needs to notify the anesthesiologist of this history prior to any surgery.
Because this primarily is an inherited condition, the most important aspect of diagnosis is obtaining a family history. In addition to asking about symptoms and your medical history, your doctor will perform a physical exam.
Attacks don’t usually occur during an office visit, so your doctor may prescribe several blood tests to check potassium levels during an attack.
Your doctor may wish to bring on an attack during an office visit. This should only be done under careful monitoring by an experienced neurologist. If an attack is triggered, several tests may be done, including:
Blood tests to look for the gene mutation or to look for antibodies that may cause these types of symptoms.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a