Hypokalemic periodic paralysis

Hypokalemic periodic paralysis
Other names	hypoKPP
This condition is inherited in an autosomal dominant manner.
Specialty	Neurology, neuromuscular medicine

Hypokalemic periodic paralysis (hypoKPP), also known as familial hypokalemic periodic paralysis (FHPP),^[1] is a rare, autosomal dominant channelopathy characterized by muscle weakness or paralysis when there is a fall in potassium levels in the blood (hypokalemia). In individuals with this mutation, attacks sometimes begin in adolescence and most commonly occur with individual triggers such as rest after strenuous exercise (attacks during exercise are rare), high carbohydrate meals, meals with high sodium content, sudden changes in temperature, and even excitement, noise, flashing lights, cold temperatures and stress. Weakness may be mild and limited to certain muscle groups, 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.

Some people only develop symptoms of periodic paralysis due to hyperthyroidism (overactive thyroid). This entity is distinguished with thyroid function tests, and the diagnosis is instead called thyrotoxic periodic paralysis.^[2]