Antacid-induced rickets in infancy.

A 3-month-old premature infant presented with a "soft skull." Clinical and radiologic findings confirmed the diagnosis of rickets. Biochemistry revealed normal serum parathyroid hormone (PTH) and undetectable urine phosphate. These findings combined with a history of 5-6 weeks' treatment with high-dose aluminum-rich antacid established the diagnosis of antacid-induced rickets. Discontinuation of the medicine combined with phosphate and vitamin D supplementation resulted in quick resolution of all clinical, radiologic, and biochemical abnormalities. Our patient demonstrates that in premature infants antacid-induced rickets can develop within a few weeks; normal serum PTH concentration and hypophosphaturia are highly indicative of the diagnosis, and contrary to the situation in adults in whom hypercalciuria has been often described, in infants hypocalciuria is more commonly observed. Pediatricians should avoid or minimize the use of aluminum-containing antacids, and when used, carefully monitor mineral metabolism.