Hypercalcemia in distal renal tubular acidosis: A case report

Abstract Introduction Hypercalcemia, defined as the total serum calcium concentration two standard deviations above the mean normal level, may be an emergency condition requiring proper initial diagnosis and immediate management. In association with nephrocalcinosis and hypercalciuria, differential diagnosis will be narrowed to limited diseases such as idiopathic hypercalciuria, hypervitaminosis A and D, and also renal tubular acidosis (RTA). Hypercalcemia is rarely presented in RTA with a few cases reported to date in the literature. Case presentation We reported a seven-month-old boy with complaints of refractory vomiting, restlessness, polyuria, polydipsia, and hypotonia. Laboratory tests revealed persistent hypercalcemia, hypokalemia, hypercalciuria, and metabolic acidosis with a normal anion gap. Bilateral nephrocalcinosis was detected in imaging studies. Based on these findings he was diagnosed with distal RTA and hypercalcemia and treated with polycitrate and Jaulie's solution. Conclusion Distal RTA should be considered as a differential diagnosis of hypercalcemia. Still, more studies are required for determining the pathway resulting in this rare association.