Endocrine Abstracts

Introduction: Neonatal Grave’s disease is rare, affecting one in 25 000 neonates, and results from transplacental passage of TSH receptor antibodies (TSHR-Ab). Whilst hyperthyroidism occurs in <5% of babies born to mothers with active Grave’s disease; those born to mothers who were previously treated may still be affected. Neonatal Grave’s disease is usually self-limiting, however, complications include craniosynostosis, growth retardation, hyperactivity, developmental and behavioural problems.

Case report: A female infant was born at term to a mother previously treated with radioiodine for Grave’s disease. Mother received routine antenatal care and remained euthyroid throughout pregnancy. However, TSHR-Ab were not assessed until 34 weeks gestation, delaying the routine alert system until after delivery. Raised maternal antibody levels were identified during routine postnatal care. The infant developed a tachycardia and an increased frequency of bowel motions. She was admitted to NNU where thyroid function tests (TFTs) at 48 h of age were highly suggestive of neonatal thyrotoxicosis; T₃ 22.7 (2.6–5.7 pmol/l), T₄ 64.3 (9–22 pmol/l), TSH <0.01 (0.35–5.00 mU/l), transplacental TSHR-Ab 25 (<0.4 U/l). Carbimazole and propranolol were started. Symptoms resolved by day 6 of life and the baby was discharged. At 6 weeks of age TFTs had normalised and propranolol was stopped. At 16 weeks of age TSHR-Ab were 0.2 U/l and carbimazole was stopped.

Conclusions: This case highlights the importance of actively exploring the risk of neonatal thyrotoxicosis in all gravid women presenting with a history of hyperthyroidism, including measuring TSHR-Ab levels at booking. We emphasise the importance of effective information sharing between adult and paediatric specialists, midwives and patients to identify high risk women early. Locally we have implemented an education programme to increase awareness of the impact of maternal factors on neonatal health. This has focused on early recognition and communication, including the use of neonatal alert cards.