title: Iodine-induced hypothyroidism in full-term infants with congenital heart disease: more common than currently appreciated?
abstract: BACKGROUND
  Iodine is a micronutrient essential for thyroid hormone synthesis. Thyroid hormone is critical for normal neurocognitive development in young infants, and even transient hypothyroidism can cause adverse neurodevelopmental outcomes. Both iodine deficiency and excess can cause hypothyroidism. Although iodine-induced hypothyroidism is well recognized in premature infants, full-term neonates have received less attention. Infants with congenital heart disease (CHD) are commonly exposed to excess iodine from administration of iodinated contrast agents during cardiac catheterization as well as topical application of iodine-containing antiseptics and dressings; hence, this is a vulnerable population.
  
  
  OBJECTIVE
  We report three cases of iodine-induced hypothyroidism in full-term neonates with CHD after cardiac angiography and topical application of iodine-containing antiseptics and dressings in the operative setting.
  
  
  RESULTS
  Three neonates with CHD and normal thyroid function at birth developed hypothyroidism after exposure to excess iodine. Two of these infants had transient hypothyroidism, and one had severe hypothyroidism requiring ongoing thyroid replacement therapy. All infants were asymptomatic, with hypothyroidism detected incidentally in the inpatient setting due to repeat newborn screening mandated by the long duration of hospitalization in these infants.
  
  
  CONCLUSIONS
  Iodine-induced hypothyroidism may be under-recognized in infants with CHD exposed to excess iodine. Systematic monitoring of thyroid function should be considered to avoid potential long-term adverse neurodevelopmental effects of even transient thyroid dysfunction in this susceptible population.
authors.affiliation: Division of Endocrinology (V.V.T., R.S.B., B.L.), Boston Children's Hospital, Boston, Massachusetts 02115; Division of Endocrinology (A.M.L.), University of California-Los Angeles, David Geffen School of Medicine, Los Angeles, California 90095; and Section of Endocrinology, Diabetes, and Nutrition (L.E.B.), Boston University School of Medicine, Boston, Massachusetts 02118.
authors.forename: V V
authors.initials: VV
authors.lastname: Thaker
authors.forename: A M
authors.initials: AM
authors.lastname: Leung
authors.forename: L E
authors.initials: LE
authors.lastname: Braverman
authors.forename: R S
authors.initials: RS
authors.lastname: Brown
authors.forename: B
authors.initials: B
authors.lastname: Levine
mesh_terms: D000891:Anti-Infective Agents, Local / Q000009:adverse effects; D001458:Bandages / Q000009:adverse effects; D003409:Congenital Hypothyroidism / Q000139:chemically induced* / Q000150:complications*; D003287:Contrast Media / Q000008:administration & dosage / Q000009:adverse effects; D017023:Coronary Angiography / Q000009:adverse effects; D005260:Female; D005865:Gestational Age; D006330:Heart Defects, Congenital / Q000150:complications* / Q000000981:diagnostic imaging; D006801:Humans; D007231:Infant, Newborn; D007455:Iodine / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced*
chemical_list: D000891:Anti-Infective Agents, Local; D003287:Contrast Media; D007455:Iodine