Feline hypokalemic polymyopathy is a generalized metabolic muscle weakness disorder in cats secondary to hypokalemia associated with excessive urinary depletion or inadequate dietary intake. Extracellular hypokalemia causes muscle cell membrane hyperpolarization and secondary excessive permeability to sodium. This leads to hypopolarization of the muscle cell and subsequent weakness.
Clinical signs include generalized weakness, ventroflexion of the neck, abnormal gait, anorexia, and muscle pain. The neurologic examination is normal. Serum chemistries reveal hypokalemia (<3.5 mEq/L) and increased creatinine and CK. The urine has a low specific gravity, and potassium excretion is increased. Treatment is by potassium supplementation, given PO (5–8 mEq/day) or IV in cats with profound hypokalemia. Prognosis is excellent with early diagnosis and treatment.