Seizures during the neonatal period have a broad differential diagnosis such as intracranial infections, structural pathology and metabolic disorders. Among them, hypocalcemia is a treatable and well-known cause of neonatal seizures. Maternal hyperparathyroidism during pregnancy suppresses parathyroid activity in the fetus resulting in transient hypoparathyroidism and hypocalcemia after birth. We report a case of neonatal symptomatic hypocalcemia leading to a diagnosis of maternal hyperparathyroidism. The relevance of early suspicion and treatment of both entities is also discussed.

Transient neonatal pseudohypoparathyroidism is an uncommon pathology that causes late neonatal hypocalcemia, hyperphosphatemia and high levels of parathyroid hormone (PTH), which reflects peripheral resistance to its action. It is a rare cause of late neonatal hypocalcemia and the biochemical defect appears to lie in a functional immaturity of renal PTH receptors. High doses of calcium and vitamin D are necesary for its correction. Its self-limited evolution differences it with other persistent pseudohypoparathyroidism. We report a case of a premature newborn with intrauterine growth retardation who presented this pathology. We analyze the clinical and biochemical findings and differential diagnosis and management of this rare disorder.