Thyrotropin response to thyrotropin-releasing hormone in elderly patients with and without acute illness.

The response of thyrotropin (TSH) to thyrotropin-releasing hormone (TRH) was measured in 70 clinically euthyroid elderly patients who were acutely ill and in 70 age- and sex-matched euthyroid controls who were free of acute disease. The incremental TSH response (delta TSH) was often blunted (less than 2 mU/l) in both groups, though more often in those with acute illness (30%) than in those without (19%). However, in patients from both groups who had a blunted delta TSH, there was often a substantial proportional rise in TSH. A substantial proportional TSH rise may be useful in differentiating between genuine thyroid disease and euthyroid sick syndrome in elderly patients with a blunted delta TSH.