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Hypokalemic paralysis is a less recognized but reversible disorder in elderly patients. This report describes two elderly Chinese males (age 74 and 78 years) who had progressive muscle weakness and eventually paralysis. Physical examination showed symmetrical flaccid paralysis of extremities. Both had the major biochemical abnormality of profound hypokalemia (1.4 and 1.8 mmol/L) accompanied by high urine K+ excretion and hyperchloremic metabolic acidosis. A positive urine anion gap and alkaline urine pointed to the diagnosis of distal renal tubular acidosis. Large doses of potassium chloride supplementation were required to restore muscle strength. Pertinent investigations, including elevated titers of antinuclear antibody and rheumatoid factor, positive anti-Ro antibody, low serum C3 and C4 levels, and delayed saliva excretion on salivary scintigraphy suggested Sjögren syndrome. Despite the lack of sicca syndrome at the initial presentation, both had development of typical sicca syndrome and positive Schirmer test at the 5-month and 1-year follow-up, respectively. Potassium citrate supplement and prednisolone therapy completely corrected the hypokalemia and metabolic acidosis. Extraglandular involvement with distal renal tubular acidosis preceding the typical sicca syndrome may induce hypokalemic paralysis and unveil Sjögren syndrome in elderly males.

Thyrotoxic periodic paralysis is a thyroid-related disorder that is manifested as recurrent episodes of hypokalemia and muscle weakness lasting from hours to days. The periodic paralysis has been associated with thyrotoxicosis from various etiologies. Although the incidence of the disorder is relatively higher among Asians, it has been reported in many other ethnic groups. We review the literature and report the ninth and tenth cases of thyrotoxic periodic paralysis in black patients.