1. The presence of an abnormally low concentration of potassium ions in the circulating blood; occurs in familial periodic paralysis and in potassium depletion due to excessive loss from the gastrointestinal tract or kidneys. The changes of hypokalemia may include vacuolation of renal tubular epithelial cytoplasm with impairment of urinary concentrating power and acidification, flattening of the T wave of the electrocardiogram, and muscle weakness.
The definition information for hypokalemia is provided by Stedman's. You can search our medical dictionary here.