Thyroid Research Thyroid Research Archive Hyperthyroidism

Accidental ingestion of high doses of thyroid hormone by children rarely causes hyperthyroidism

(March 2004)

The background of the study. Thyroxine (T4) and other thyroid hormone products may be accidentally ingested by children. This study describes the findings in children who ingested large amounts of thyroid hormone.

How the study was done. Between 1983 and 2000, 30 children less than five years of age who had accidentally ingested thyroid hormone were seen in an emergency department. Information concerning how much thyroid hormone, the type of hormone, and the timing of the ingestion was obtained from the parents. The children were treated by stomach lavage and then given charcoal to bind hormone in the gastrointestinal tract.

The results of the study. The 30 children ranged in age from 1 to 5 years. Seven had ingested from 300 to 9500 µg of T4, one 600 µg of triiodothyronine (T3), and 16 both, in amounts ranging from 80 µg of T4 + 20 µg of T3 to 2500 µg of T4 + 630 µg of T3. The dose was not known in the others. Seven children were followed as outpatients and 23 were hospitalized. Only eight children had any signs of hyperthyroidism (usually rapid heart rate), and none had any neurologic abnormalities.

The initial serum T4 concentrations ranged from normal to 8 times normal, and the initial serum T3 concentrations ranged from normal to 18 times normal. In four children the hormones were measured repeatedly for up to 5 days after the ingestion. The values were highest 4 to 24 hours after the ingestion, and had fallen by 50 percent at 48 to 72 hours. There was no relationship between the serum T4 and T3 concentrations and any symptoms or signs of hyperthyroidism.

The conclusions of the study. Children who accidentally ingest large amounts of thyroid hormone may have very high serum thyroid hormone concentrations, but rarely have any symptoms of hyperthyroidism.

The original article. Willgerodt H, Keller E, Sorger D, Hoepffner W. Acute ingestion of thyroxine and triiodothyronine in young children. Eur J Pediatr 2003;162:639-41.