Hypothyroidism secondary to topical iodine treatment in infants with spina bifida.

Four infants with spina bifida, who had not undergone surgical closure of a lumbar myelomeningocele, were assessed and investigated for hypothyroidism. From birth, all were treated once daily with an iodine-containing ointment (Betadine) as a local antiseptic applied to the spina defect. All infants showed excess urinary iodine concentration. Two infants, without clinical evidence of hypothyroidism or goitre, showed low serum free thyroxine and high thyroid stimulating hormone concentrations at a mean age of four weeks and were started on thyroxine replacement treatment. Betadine ointment and thyroxine were stopped simultaneously at a mean age of nine months, following which all infants remained euthyroid. Thyroid function tests should be monitored routinely if iodine is applied as a topical antiseptic to infants.