Hypokalemic periodic paralysis in Sjögren's syndrome.

A 30-year-old woman had scleroderma, Sjögren's syndrome, deforming polyarthritis, distal renal tubular acidosis, hypokalemic periodic paralysis, and persistent mild myopathy. During a five-year period the patient's otherwise mild course of disease was complicated by the occurrence of five episodes of severe flaccid muscle paralysis involving both proximal and distal muscle groups. Between the paralytic episodes the patient functioned well without replacement therapy, and had normal potassium levels. The sicca component was mild and went unrecognized for several years. There was no family history of muscle disease. The data presented in this report support the view that the paralytic episodes were due to hypokalemia secondary to renal tubular acidosis associated with Sjögren's syndrome. Hypokalemic periodic paralysis may occur as a rare complication of Sjögren's syndrome and renal tubular acidosis.