Challenges in management of abnormal thyroid function tests in unwell infants: A tertiary centre real-world experience

Abstract

Aim

Abnormal thyroid function tests (TFTs) are found in a wide range of settings in hospitalised infants. This retrospective descriptive study reviewed management decisions and outcomes of these infants, identifying factors influencing clinicians' decision to treat with thyroxine.

Methods

Data were collected for all infants referred to the on-call endocrinology service at a tertiary Australian centre for thyroid dysfunction between 1 July 2019 and 30 June 2021. Electronic medical records were reviewed for birth and neonatal factors, TFTs, relevant investigations, treatment and disposition.

Results

Of 124 infants referred to the service over a 2-year period, 43% (52 out of 120) were premature, with a high rate of comorbidities, including jaundice, hypoglycaemia, respiratory distress and cardiac anomalies. About 57% (69 out of 121) of referrals to the service were from neonatal intensive care units. Investigations to evaluate hypothyroidism included nuclear thyroid scans in 40% (46 out of 114) and ultrasound in 37% (41 out of 112). Levothyroxine treatment was initiated in 66% (77 out of 117) of infants, with 63% (73 out of 117) assigned a presumptive diagnosis of transient congenital hypothyroidism. At the end of the study period, 70% (54 out of 77) remained on thyroid replacement.

Conclusion

Our study demonstrates the challenge clinicians face when deciding whether to treat premature and medically unwell infants with abnormal TFTs. Further prospective studies are required to determine predictors of permanent CH in this complex population.