Recurrent Hypokalemic Paralysis as the Initial Presentation of Primary Sjögren's Syndrome.

Distal renal tubular acidosis (dRTA) is associated with autoimmune disorders, particularly Sjögren's syndrome. Hypokalemic muscle weakness due to dRTA is an uncommon presentation of Sjögren's syndrome and may mimic primary hypokalemic periodic paralysis, resulting in a diagnostic delay. We present the case of a 35-year-old woman who reported recurrent limb weakness in the presence of hypokalemia (serum potassium: 2.7 mmol/L). She had previously been diagnosed with primary hypokalemic periodic paralysis, but this diagnosis was challenged as she was found to have normal anion gap metabolic acidosis and an alkaline urine pH with significant potassium wasting. The patient reported the presence of subtle sicca symptoms only on direct questioning. Further workup revealed positive serology for Sjögren's syndrome. She was managed with potassium and sodium bicarbonate replacement and given oral steroids and azathioprine for long-term management. Following correction of electrolyte abnormalities, the patient's muscle strength improved significantly, and she regained functional mobility. Her metabolic acidosis also resolved, and she experienced no further episodes of weakness or electrolyte imbalance during 12 months of follow-up. Primary Sjögren's syndrome-associated distal RTA should be considered in patients presenting with recurrent hypokalemic paralysis, particularly in the presence of normal anion gap metabolic acidosis and alkaline urine pH. Early treatment prevents recurrent paralysis and long-term renal complications.