[Neonatal hyperthyroidism: A sometimes challenging diagnosis].

Graves disease complicates two pregnancies out of 1000 and when it is known before pregnancy, it warrants careful monitoring of the fetus and the newborn. We report on a case of neonatal hyperthyroidism, which revealed a previously unknown maternal thyroid disease. In this situation, neonatal signs can be misinterpreted, delaying the diagnosis. Neonatal hyperthyroidism is, however, a therapeutic emergency because of the risk of cardiac and neurological complications. The neonatologist must identify thyroid disease in the absence of a maternal history in order to promptly start therapy.