Thyroid Research Thyroid Research Archive Hyperthyroidism

Ground beef patties can cause hyperthyroidism

(November 2003)

The background of the study. High doses of thyroid hormone can cause hyperthyroidism, and sometimes the source of the excess thyroid hormone is not obvious. This case report describes a woman who had several episodes of hyperthyroidism caused by ingestion of beef patties that contained thyroid tissue.

Case report. A 61-year-old woman consulted her physician because of weight loss (4 kg), palpitations, and increased perspiration of several weeks' duration. She had a rapid heart rate and tremor. Her thyroid was not enlarged. Her serum free thyroxine concentration was high and her serum thyrotropin concentration was low, confirming the diagnosis. She improved with no treatment; eight weeks later her serum free thyroxine concentration was normal.

Review of her record revealed that this was her fifth episode of hyperthyroidism in the preceding 10 years. At approximately two-year intervals, she had symptoms of hyperthyroidism for 8 to 12 weeks that subsided without treatment. During several episodes she had low radioiodine uptake values, normal serum antithyroid antibody concentrations, and low serum thyroglobulin concentrations; these findings suggested thyroid hormone therapy, which she had never received.

A source of exogenous thyroid hormone was sought. The patient and her husband lived on a farm, and they periodically slaughtered a cow for their meat. Further inquiry revealed that their butcher removed thyroid tissue along with the muscles of the larynx (gullet trimmings), and then used all this tissue to prepare ground meat. The patient, but not her husband, who never had any symptoms of hyperthyroidism, ate patties prepared from this ground meat for a few months after it was prepared. No ground meat was available for analysis.

The conclusions of the study. Ingestion of ground meat prepared from neck muscle that includes thyroid tissue can cause hyperthyroidism.

The original article. Parmar MS, Sturge C. Recurrent hamburger thyrotoxicosis. CMAJ 2003;169:415-7.