Background: Neonatal thyrotoxicosis, a rare and life-threatening condition, is caused by transplacental transfer of thyroid stimulating immunoglobulins from mother to infant. While clinical features may include goitre, prominent eyes and poor weight gain, these may be absent in some cases. Early diagnosis and treatment of affected infants is critical.
Objective: We report a case series of infants with neonatal thyrotoxicosis from two tertiary paediatric hospitals.
Methods: Case notes of four infants with neonatal thyrotoxicosis were reviewed. Details of maternal thyroid disease, perinatal course, clinical features, diagnostic tests and management of infants were recorded.
Results: All infants were born to mothers with known Graves disease. Three of four mothers had positive thyroid receptor antibodies during the third trimester of pregnancy. In two of four cases, isolated tachycardia was the only clinical finding. Mean age at diagnosis was 6 days (range 210 days). Three infants were treated with carbimazole alone and one infant receive a combination of carbimazole, iodine and propanolol. Mean duration of therapy was 11 weeks (range 624 weeks). One infant became biochemically hypothyroid during treatment and required thyroxine replacement. All infants were thriving, developmentally normal and euthyroid at follow-up.
Conclusion: This case series illustrates the importance of antenatal risk assessment, early recognition, prompt treatment and close follow-up of infants with neonatal thyrotoxicosis. Maternal thyroid receptor antibodies should be measured in the third trimester. Isolated tachycardia may be the only clinical feature. In infants taking anti-thyroid medications, weekly thyroid function testing and dose titration is important to avoid late-onset hypothyroidism.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology