**5. Manifestations and clinical diagnosis**

In most cases, infants—even those at risk—are asymptomatic. Nevertheless, an infant who is apathetic and refusing feeds and has a feeble cry should heighten suspicion of hypoglycemia. In high-risk infants, major findings include fine tremors, acrocyanosis, seizures, and apnea; if left untreated, coma and death may follow.

After birth, neonates born to mothers with diabetes develop complications related to their hyperinsulinemic state. In the first 3 days of life, these infants may exhibit episodes of irritability, tremor, and hyperexcitability or may present with hypotonia, lethargy, and weak suckling—manifestations consistent with early development of hypoglycemia and late onset of hypocalcemia. However, one must bear in mind that these infants are sometimes asymptomatic and the absence of symptoms should not delay testing for hypoglycemia.

The presence of tachypnea in the first days of life may be a transient manifestation of hypoglycemia, hypothermia, polycythemia, heart failure, cerebral edema secondary to traumatic delivery (particularly in macrosomic infants), or asphyxiation. The incidence of respiratory distress syndrome is high in these infants, since hyperinsulinemia may alter fetal lung maturation, inhibiting the development of enzymes required for the synthesis of pulmonary surfactant.
