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Severe hypothyroidism following a single topical exposure to iodine in a premature neonate
  1. Catherine Mary Breen,
  2. Monica Fahim Salama and
  3. Michael A Boyle
  1. Department of Neonatology, Rotunda Hospital, Dublin, Ireland
  1. Correspondence to Dr Catherine Mary Breen; catherinebreen1411{at}


A neonate, born at 24 weeks, underwent a patent ductus arteriosus ligation, with previous normal thyroid stimulating hormone (TSH) levels, developed severe hypothyroidism from topical exposure to iodine following a single surgical procedure at 28 days of life. A low free T4 level of 0.05 ng/dL and a high TSH level of 228 mIU/L was detected with an increased urinary iodine excretion level of 178 mg/L (reference range 0.30–1.97 mg/L). The thyroid ultrasound was normal. Levothyroxine was started immediately but thyroid function did not recover fully during admission and levothyroxine was required beyond term corrected. This case highlighted how susceptible extremely preterm infants are to iodine induced hypothyroidism, even short-term topical exposure. Delayed treatment of hypothyroidism can lead to profound neurodevelopmental delay. As surgical advances allow for interventions at earlier gestations, the importance of early thyroid function testing postexposure to iodine is highlighted and ultimately topical iodine should be avoided in these susceptible infants.

  • drugs: endocrine system
  • neonatal intensive care
  • interventional cardiology

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  • Contributors All authors contributed to the conception and design of the case. CMB and MFS wrote up the case and revised it as necessary and all work was supervised by MAB. All authors are in agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Parental/guardian consent obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.