High rate of hypothyroidism among patients treated for multidrug-resistant tuberculosis in Lesotho

BACKGROUND: Hypothyroidism is a known side effect of treatment for multidrug-resistant tuberculosis (MDR-TB), but it is considered to be rare. Hypothyroidism has vague and non-specific symptoms, and can be easily missed by clinicians. OBJECTIVE: To report the high rate of hypothyroidism in a cohort of MDR-TB patients in Lesotho and to describe our approach to diagnosis and management. DESIGN: A retrospective study of 212 patients who initiated treatment for MDR-TB in Lesotho between 27 July 2007 and 24 March 2009 was performed. RESULTS: Among 186 patients screened, 129 (69%) had hypothyroidism, defined as at least one documented thyroid-stimulating hormone (TSH) result > 10.0 mIU/l; 100 (54%) patients had a maximum TSH > 20.0 mIU/l. At 93 days after starting MDR-TB treatment, half of the patients had developed hypothyroidism. CONCLUSION: Hypothyroidism may be more common during MDR-TB treatment than previously recognized. Screening all patients, even those without symptoms, for hypothyroidism within 2-3 months of starting MDR-TB treatment should be considered until prospective studies can inform screening guidelines.