ATRAUMATIC DISTAL TIBIAL FRACTURE AS THE FIRST PRESENTATION OF SJOGREN SYNDROME WITH DISTAL RENAL TUBULAR ACIDOSIS, HYPOKALEMIC PARESIS, AND NEPHROCALCINOSIS

Distal renal tubular acidosis (dRTA) is an uncommon disorder characterized by impaired distal urinary acidification resulting in persistent metabolic acidosis. In adults, acquired dRTA is frequently associated with autoimmune diseases, particularly Sjogren syndrome. Chronic metabolic acidosis contributes to nephrocalcinosis and metabolic bone diseasewhereas severe hypokalemia can lead to acute neuromuscular weakness. In the past, osteomalacia and fractures have been reported in patients with Sjögren syndrome-associated dRTA, but atraumatic fracture as the first event preceding recognition of an underlying autoimmune disease remains an uncommon presentation.We report a case of a 45-year-old woman with primary hypothyroidism on treatment who presented with acute progressive weakness of all four limbs following two days of vomiting and diarrhea. On further history, she reported a right leg fracture two months earlier that had occurred while briskly walking. On examination she had generalized hypotonia, 4/5 power in all four limbs, and diminished deep tendon reflexes. Laboratory investigations reported severe hypokalemia (2.64 mmol/L), hyperchloremia (113.4 mmol/L), and normal-anion-gap metabolic acidosis (pH 7.30, bicarbonate 9.2 mmol/L). Urine pH was alkaline at 7.5 with spot urine electrolytes suggestive of a positive urine anion gap. Ultrasonography demonstrated bilateral nephrocalcinosis.