[PULMONARY TUBERCULOSIS AND TUBERCULOUS PLEURISY COMPLICATED WITH RIFAMPICIN-INDUCED HYPOTHYROIDISM: A CASE REPORT].

: Rifampicin can induce hypothyroidism. We report a case of pulmonary tuberculosis and tuberculous pleurisy that was complicated by rifampicin-induced hypothyroidism. The patient received rifampicin-based tuberculosis treatment and experienced persistent appetite loss, which led us to pro- vide concomitant hypothyroidism treatment. An 85-year-old woman with no underlying thyroid-related disease presented to her local hospital with a 3-month history of appetite and weight loss. A chest radiograph revealed pleural effusions and infiltrative shadows in the lower fields of both lungs, and we also detected high levels of lympho- cytes and adenosine deaminase levels (49.6 IU/1) in the pleu- ral effusion, with positive results from a polymerase chain reaction assay of a sputum sample. Thus, we diagnosed the patient with pulmonary tuberculosis and tuberculous pleurisy, and initiated treatment using isoniazid, rifampicin, etham- butol, and pyrazinamide. Her clinical course was good and her anorexia was improved. However, she subsequently experienced recurrent appetite loss, malaise, and bilateral lower-leg edema. Follow-up laboratory testing revealed that she had developed hypothyroidism. We started treatment using levothyroxine without interrupting the tuberculosis treatment. The loss of appetite and other thyroid-related symptoms were improved. The patient's thyroid function had been normal at her admission, and there were no findings of Hashimoto's thyroiditis or other thyroid conditions. Based on the clinical course, we conclude that the rifampicin induced the hypothyroidism. Therefore, rifampicin-induced hypothyroidism should be considered in cases with persistent appetite loss, even if the patient appears to be experiencing anorexia as an adverse drug reaction.