Vitamin D hypersensitivity discovered in a case of urinary tract infection

Abstract

Vitamin D hypersensitivity with severe hypercalcemia is uncommon in the neonatal and infancy period. We report a case of 4-month-old infant under mixed feeding, who received 200 000 UI of vitamin D3 on the 15th day of life. She was admitted for a febrile urinary tract infection. Kidney ultrasound showed bilateral grade III nephrocalcinosis. Laboratory investigations showed hypercalcemia and hypercalciuria, 1-25 hydroxyvitamin D was very high, the dosage of PTH and 25-hydroxyvitamin D was normal. The patient was treated with biphosphonate with good results. Genetic sensitivity and metabolic differences appear to influence the level of active vitamin D. A review of recommended dose of vitamin D in our country should be discussed to reduce the risk of toxicity.