Pulmonary tuberculosis and its therapy do not significantly affect thyroid function tests.

Basal thyrotropin, total thyroxine, total tri-iodothyronine and free tri-iodothyronine were measured in 30 HIV-negative patients with focal pulmonary tuberculosis upon starting and after one and two weeks of isoniazid, rifampicin and pyrazinamide therapy. Rapid and statistically significant elevations in free tri-iodothyronine and total tri-iodothyronine were noted after the first and second week of treatment respectively. For most patients, however, hormone levels remained within normal limits throughout the study. Overall, the effects of pulmonary tuberculosis and of its therapy on the thyroid function parameters examined, in otherwise healthy individuals, appear to be minimal.