Overlap syndrome of systemic lupus erythematosus and Sjögren’s syndrome presenting with distal renal tubular acidosis

Distal renal tubular acidosis (dRTA) is a rare but clinically significant renal manifestation of autoimmune diseases, particularly overlap syndromes involving systemic lupus erythematosus (SLE) and Sjögren’s syndrome. We report the case of a 33-years man who presented with acute limb weakness secondary to severe hypokalaemia. Her biochemical profile revealed normal anion gap metabolic acidosis and elevated urine pH, consistent with dRTA. Immunological testing and histopathology confirmed the diagnosis of overlap syndrome involving SLE and Sjögren’s syndrome. She was successfully managed with potassium supplementation, immunomodulatory therapy, and symptomatic treatment. This case highlights the importance of considering autoimmune aetiologies in patients with unexplained hypokalaemia and metabolic acidosis, particularly in the presence of sicca symptoms.