Neonatal thyroid storm: the importance of an accurate antenatal history.

A near-term infant became unwell immediately after birth with cardiorespiratory compromise-persistent tachycardia, pulmonary hypertension and reduced cardiac function. There had been no concerns during the pregnancy and the obstetrical and maternal medical history was unremarkable apart from hypothyroidism. A thyroid function test on admission revealed a significantly elevated free T4 and a diagnosis of a thyroid storm was made.