A neonate with late-onset hypocalcemia due to unrecognized maternal hyperparathyroidism and a systematic overview of similar cases.

Neonatal seizures are alarming manifestations of an underlying significant disorder demanding immediate attention and intervention. Hypocalcemia, although rare, must be considered in the differential diagnosis of neonatal seizures. We present an unusual case of a 10-day-old infant with unexplained symptomatic hypocalcemia, experiencing multiple episodes of focal tonic-clonic seizures, born by an entirely asymptomatic mother. Moreover, we conducted a systematic search in PubMed and Scopus databases to present a clinical overview of all similar cases. Maternal laboratory investigation revealed markedly increased calcium levels with concomitant high parathyroid hormone levels due to a parathyroid adenoma, undiagnosed during antenatal checkup. This is one of the few cases in the literature where neonatal symptomatology led to the diagnosis of undiagnosed maternal hyperparathyroidism. Early detection and appropriate management of neonatal hypocalcemia could eliminate serious maternal and fetal morbidity.