An infant with hypercalcemia: Questions

A 6-month-old male infant born by normal vaginal delivery (birth weight 3.150 kg, length 49 cm) and affected by hypospadias underwent renal ultrasound scan (Fig. 1). Expert advice was required after an “uncertain renal US report”. The patient suffered decreased appetite, vomiting, constipation, polyuria and polydipsia during the previous 2 months. At our appointment, we found hypotonia, irritability, failure to thrive, anterior fontanelle 1.5×1 cm, and moderate dehydration. His mother reported that the infant was taking no drugs except prophylaxis with vitamin D (400 IU/day). Serum chemistry was as follows: calcium 18.67 mg/dl (normal range, 8.4–10.2 mg/dl), urea 65 mg/dl (10–50 mg/ dl), creatinine 0.45 mg/dl, phosphorus 5.7 mg/dl, Ca×P 106 mg (normal value