Hyperkalemic paralysis (adynamia episodica hereditaria): Report of four cases and clinical studies

Abstract

Four patients with hyperkalemic paralysis (adynamia episodica hereditaria) are described, and clinical studies are reported. The responses to therapy with oral glucose and potassium chloride, intravenous calcium and bicarbonate, hyperventilation and carbon dioxide inhalation were studied. The electrocardiographic response of six nonhyperkalemic subjects to orally administered glucose and the responses of two normal subjects to 10 gm. of orally administered potassium chloride were also studied. In two patients with hyperkalemic paralysis, ingestion of 250 gm. of glucose caused pronounced changes in the S-T segment and T wave in the electrocardiograms, but the patients were asymptomatic. The same electrocardiographic changes did not occur in the nonhyperkalemic subjects. In the patients, the electrocardiographic changes were reversed quickly after the ingestion of potassium chloride. After the administration of 7.5 and 10 gm. of potassium chloride, the serum potassium rose rapidly, to a level higher than that seen in the non-hyperkalemic subjects. At this point symptoms of weakness and paralysis occurred. The patients were treated with 20 to 40 gm. of glucose administered orally four to five times per day and showed marked improvement. On the basis of our clinical studies it is postulated that the primary defect in this disease is an alteration in the potassium transport system of skeletal muscle. Potassium appears to be unable to cross the cell membrane in both directions and tends to accumulate at the muscle membrane. It is suggested that the substantial part of the intracellular potassium in a bound form is under the influence of cold and or exercise and enters the free ionic state, resulting in persistent depolarization of the muscle membrane and thus leading to weakness and paralysis. Glucose appears to be effective by overcoming part of the impedence to potassium transport by operating through the active transport mechanism of the cell. A high sodium diet (250 mEq.) prevented paralysis induced by 5.0 gm. of potassium chloride in one patient who was on a low sodium diet (8 mEq.). Paralysis induced by 7.5 gm. of potassium chloride was lessened in severity by the high sodium diet as compared to the low sodium diet. These findings are discussed in terms of the primary defect postulated for this disease.