Hypokalemic periodic paralysis

Hypokalemic periodic paralysis is a rare autosomal dominant channelopathy marked by attacks of muscle weakness or paralysis that accompany a fall in blood potassium. Attacks often begin in childhood or adolescence and are triggered by rest after strenuous exercise, large carbohydrate or salty meals, sudden temperature changes, stress or certain medications. They can last from hours to days, and strength usually returns between attacks, though some people develop lasting weakness later in life. A related form that appears only with an overactive thyroid is called thyrotoxic periodic paralysis. Mutations in muscle ion channel genes underlie the condition, although many cases are sporadic. In 1935 the Scottish physician Mary Walker first recognised the link with low potassium and described the glucose challenge test and intravenous potassium treatment.