Neonatal thyrotoxicosis may occur by transplacental transfer of thyroi
d stimulating immunogloubins from the mother, Although the clinical ma
nifestations may vary in the new born period, hyperthyroidism has been
associated with several cardiac complications including supraventricu
lar tachycardia, cardiomyopathy and congestive cardiac failure. We rep
ort the case of a nine day old baby who presented with severe pulmonar
y hypertension in association with congestive cardiac failure secondar
y to neonatal thyrotoxicosis. Treatment of the heart failure and resto
ration of the thyroid function resulted in complete regression of the
pulmonary hypertension. The recognition and reversibility of pulmonary
hypertension in neonatal Graves disease has not been previously descr
ibed.