Uncommon cribfellows: an infant with hypercalcemia, nephrocalcinosis, and acidosis: Answers

Excerpt

Nephrocalcinosis in infancy has been generally associated with prematurity, furosemide use, conditions associated with hypercalcemia, distal renal tubular acidosis (dRTA), Bartter syndrome, Dent’s disease, primary hyperoxaluria, hereditary hypophosphatemic rickets with hypercalciuria, and familial hypomagnesemia with hypercalciuria and nephrocalcinosis. Given that the patient demonstrated both hypercalcemia and acidosis, we considered the differential diagnosis for both conditions independently. Causes of hypercalcemia in this age group include subcutaneous fat necrosis, nutritional (excessive intake of calcium or vitamin D), hyperparathyroidism, malignancy, Williams’ syndrome, idiopathic infantile hypercalcemia, familial hypocalciuric hypercalcemia, and congenital lactase deficiency. In addition, nephrocalcinosis is also commonly observed in patients with dRTA as a consequence of chronic acidemia which may result in both hypercalciuria from calcium and phosphate release from the bone and hypocitraturia as proximal tubular reabsorption of citrate is enhanced under these circumstances. …