Thyrotoxicosis and Periodic Paralysis: Improvement with Beta Blockade

Periodic paralysis associated with thyrotoxicosis was observed in three unrelated American Indian males and one white male of Russian-Jewish descent. Hypokalemia was observed in all patients on at least one occasion, and in three of the patients this coincided with an episode of paralysis. In all cases, correction of the thyrotoxic state was accompanied by resolution of the episodes of paralysis. In two patients, beta-adrenergic blockade induced with propranolol therapy resulted in marked relief of the episodes of paralysis and improvement of thyrotoxic manifestations. These observations suggest that the episodic muscle paralysis seen with thyrotoxicosis may be related to the hyperadrenergic state characteristic of this disorder. Propranolol may be an important therapeutic adjunct in the management of this form of periodic paralysis.