Endocrine Abstracts

Introduction: Hypocalcaemia is a recognised cause of neonatal seizures most often related to vitamin D deficiency in the mothers of exclusively breast fed infants. There have also been case reports of an underlying diagnosis of hyperparathyroidism in a reportedly well mother becoming apparent after the infant presents with hypocalcaemic seizures. Maternal hypercalcaemia suppresses parathyroid activity in the foetus, which causes transient neonatal hypocalcaemia.

Case description: A 7-day-old male baby born at term following an uneventful pregnancy presented with focal seizures. Admission blood tests revealed hypocalcaemia Ca 1.45 mmol/l (2–3 mmol/l) alongside low magnesium 0.65 mmol/l (0.7–1.0 mmol/l) and vitamin D levels 37 nmol/l (24–76 nmol/l) with an inappropriately low PTH of <3 ng/l (14–72 ng/l). The baby required i.v. boluses of calcium followed by a calcium infusion. MRI head, renal ultrasound, metabolic screen and chest X-ray were all normal. Maternal bloods revealed hyperparathyroidism with a PTH of 105 ng/l (14–72 ng/l) and hypercalcaemia 2.95 mmol/l (2.2–2.6 mmol/l). The patient became seizure free 4 days after admission. The patient was discharged on calcium, cholecalciferol and alfacalcidol. Calcium and vitamin D normalised and were stopped after 5 weeks of treatment. The patient is currently undergoing weekly blood tests with gradual weaning of the alfacalcidol. Maternal parathyroid scan showed a left sided upper pole adenoma measuring 17.5 mm×10.3 mm. Mother has been referred for a parathyroidectomy and further investigations.

Conclusion: Maternal hyperparathyroidism is a rare cause of neonatal hypocalcaemia which can be both severe and prolonged with treatment required for up to 5 months. Although rare, this and other case reports highlight the importance of checking the parathyroid hormone and the calcium levels of mothers when their infant presents with hypocalcaemic seizures even if the mother is asymptomatic.