[Diagnostic problems in neonatal hypocalcemia]

Fifteen newborns were studied in the neonatal ICU of the Infantile Hospital of Tamaulipas in whom ICH, neural infection, tetanus, HIE++ and electrolyte disturbances were ruled out, with clinical data highly suggestive of hypocalcemia. Determination of both QTc and QoTc intervals by ECG and measurement of levels of total serum calcium and calcium in CSF and calculation of ionic calcium by means of the McLean Hastings nomogram were made in each patient. Calcium gluconate was administered IV as a therapeutic test. Presence and disappearance of clinical manifestations were correlated with laboratory tests during the suspicious period, 8 and 24 hours after treatment was begun. There was no correlation between clinical features and QTc or QoTc, nor between total serum, CSF or ionic calculated calcium. We conclude that the diagnosis of hypocalcemia in centers that do not have the specific electrode for direct Ca +/- measurement, should be sustained basically when after IV administration of Ca, symptomatology disappears and that the real usefulness of laboratory determination of total C, of ionic calcium, of QTc and QoTc is very limited.