Hypercalcemia,hypercalciuria and nephrocalcinosis in a breast-fed term newborn: a rare presentation

Although hypercalcemia and hypercalciuria are known to occur in breast-fed pre-term infants,to the best of our knowledge,it has never been reported in a term baby previously. We report a term male baby who was followed-up during pregnancy for having bright kidneys,but a follow-up renal ultrasound (US) after birth had revealed normal scan. Laboratory investigations revealed normal serum calcium (Ca),phosphorous (PO4) and alkaline phosphatase (ALP). The baby was being fed by breast milk. Follow-up US two months later showed early nephrocalcinosis along with hypercalcemia and hypercalciuria; by the age of three months,nephrocalcinosis was more extensive and the serum Ca level was more than 12 mg/L with hypercalciuria. Parathyroid hormone (PTH), phosphorous (PO4),ALP and thyroid function tests were all normal. Antenatal history revealed a hypothyroid mother who was maintained on L-thyroxin,calcium and vitamin D supplement during pregnancy. Her blood tests showed normal serum Ca,low PO4 and elevated PTH. The baby was diagnosed to have hypercalciuria and hypercalcemia secondary to maternal hypophosphatemia (maternal vitamin D deficiency). Breast feeding was stopped and the baby was started on formula,whereby he showed remarkable improvement both for his blood chemistry as well as his hypercalciuria.