Transient neonatal hypoparathyroidism: report of four cases

Neonatal hypocalcemia (NH) is common in the neonatal period. Its cause falls into one of two clinical categories, early NH occurs in first 24-48 hours of life; late NH is observed at the end of the first week of life. NH due to congenital hypoparathyroidism, either permanent or transient, is rare. They both present with hypocalcemia, low levels of intact parathyroid hormones, and hyperphosphatemia. In this paper we report on four cases of neonatal hypocalcemia due to transient hypoparathyroidism. They are all full-term infants with normal birth weights, carried by nondiabetic mothers. The age of onset was 6 days old to 17 days old, there were three male and one female. Seizure was the major symptom except for case 2, who had a high pitch crying, irritability and opisthotonus. Laboratory data revealed calcium: 4.7 to 6.3 mg/dl, phosphorus: 6.8 to 9.2 mg/dl, and magnesium: 1.2 to 2.8 mg/dl. The intact parathyroid hormone levels were abnormally low in two cases (<13 pg/ml and 5.7 pg/ml), yet only subnormal in the other two (25.2 pg/ml and 22.2 pg/ml). Further studies on these four babies showed no evidence of Di George syndrome. Interestingly, two patients' mothers were found to have hyperparathvroidism. In conclusion, in case of neonatal hypocalcemia, measurements of calcium, phosphorus, and intact-PTH in neonates are required to recognize hypoparathyroidism. Pediatricians should always check maternal parathyroid status to rule out maternal hyperparathyroidism.