Hypokalemic periodic paralysis

Hypokalemic periodic paralysis (hypoKPP) is a rare channelopathy characterized by repeated, temporary attacks of muscle weakness or paralysis that are the result of a fall in potassium levels in the blood. Hypokalemic periodic paralysis can be either genetic or acquired (not life long), and is classed as a form of acute flaccid paralysis, and has been described in people with severe myalgic encephalomyelitis.

Weakness may be mild and limited to certain muscle groups, resulting in partial paralysis or paresis, or more severe full-body paralysis. During an attack reflexes may be decreased or absent. Hypokalemic periodic paralysis attacks may last for a few hours, or persist for several days. Recovery is usually sudden when it occurs, due to release of potassium from swollen muscles as they recover.

Prevalence
Hypokalemic periodic paralysis is to be rare in the general population, but has been found in people with ME/CFS, especially in people with severe and very severe ME.

Symptom Recognition
Hypokalemic periodic paralysis was only discovered fairly recently.

The International Consensus Criteria and the International Consensus Primer refer to channelopathies and ion transportation problems, but do not mention hypokalemic periodic paralysis directly.

Notable Studies
2003, Paralysis: A qualitative study of the people with Severe Myalgic Encephalomyelitis

Possible Causes
In individuals with this genetic mutation, attacks often begin in adolescence and most commonly occur: Weakness may be mild and limited to certain muscle groups, resulting in partial paralysis or paresis, or more severe full-body paralysis. During an attack reflexes may be decreased or absent. Attacks may last for a few hours or persist for several days. Recovery is usually sudden when it occurs, due to release of potassium from swollen muscles as they recover. Some patients may fall into an abortive attack or develop chronic muscle weakness later in life.
 * on awakening or after sleep
 * after rest following strenuous exercise (attacks during exercise are rare)
 * after high carbohydrate meals
 * after meals with high sodium content (high salt content)
 * as a result of sudden changes in temperature, or cold temperatures
 * sensory input, such as noise, or flashing lights cause trigger paralysis
 * and even excitement.

Potential Treatments
Electrolytes are one of the suggestions for treating energy metabolism and ion transportation problems in ME. Potassium would seem the obvious electrolyte.

Learn more
Channelopathies (review) - Kim June-Bum.

Periodic Paralysis - What clinicians should know