Periodic Paralysis Syndrome

(Familial Periodic Paralysis; Hypokalemic Periodic Paralysis; Anderson-Tawil Syndrome; Paraneoplastic Periodic Paralysis)


Periodic paralysis is a rare condition that is usually inherited. It causes occasional episodes of severe muscle weakness. The 2 most common types of periodic paralysis are hypokalemic and hyperkalemic.


Periodic paralysis is a condition that is present from birth. Periodic paralysis is caused by abnormalities of the electrolyte channels on muscles. Familial periodic paralysis is inherited, but may occur without a known family history. With the inherited form of the disorder, only 1 affected parent is needed to transmit the gene to the baby. Rarely, the condition occurs as a result of a noninherited genetic defect.
Genetic Material
Chromosome DNA
Copyright © Nucleus Medical Media, Inc.

Risk Factors

Factors that increase your chance of developing periodic paralysis include:
  • Family history of periodic paralysis
  • Thyroid disorder—high thyroid hormone levels, particularly in Asian males


Although muscle strength returns to normal between attacks, repeated episodes of weakness may lead to chronic muscle weakness later in life. The person remains alert and aware during attacks. There is no loss of sensation.Episodes of severe weakness in the arms and legs are the major symptom. Typically, these episodes occur during sleep, early morning, or after strenuous activity. Cold, stress, and alcohol may also produce attacks. Other, less common, symptoms may include:
  • Weakness in the eyelids and face muscles
  • Muscle pain
  • Irregular heartbeats
  • Difficulty breathing or swallowing—This requires emergency care
Some features are specific to the type of periodic paralysis.
  • Hypokalemic:
    • Potassium levels 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
  • Hyperkalemic:
    • Potassium levels are high or normal during attacks
    • Attacks are usually shorter, 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 is 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 general anesthesia . Anyone with a family history of periodic paralysis needs to notify the anesthesiologist of this history prior to any surgery.

leave comments
Did you like this? Share with your family and friends.
Related Topics:
Current Research From Top Journals

Water Before Meals May Promote Weight Loss
August 2015

A randomized trial found that drinking water before main meals led to higher weight loss than those who were asked to imagine a full stomach before main meals. Water preloading is believed to help create a feeling of fullness or satiety during the meal, which may help curb overeating.

dot separator
previous editions

Fecal Transplants Induce Ulcerative Colitis Remission
July 2015

Exercise Associated with Healthy Baby Weight
June 2015

Mindful Meditation May Reduce Symptoms and Complications of Insomnia
May 2015

dashed separator


Our Free Newsletter
click here to see all of our uplifting newsletters »