Endocrine Abstracts

Background Tuberculosis of the thyroid gland is an extremely rare disease. Thyroid dysfunction is uncommon in this patient population with the majority of reported cases being clinically and biochemically euthyroid.

Case History A 28-year-old man from India and resident in Ireland for previous 2 years presented with a six week history of cough, generalised weakness, night sweats, heat intolerance and 9 kilogram weight loss. On examination a firm, multi-nodular, non-tender, mobile goitre with associated cervical lymphadenopathy was noted. Investigations revealed bulky right hilar and right paratracheal enlargement, right middle lobe infiltrate and elevated inflammatory markers. Ultrasound of thyroid showed multiple nodules throughout the thyroid gland. Technetium pertechetate scan of thyroid showed no appreciable uptake of radio isotope within the thyroid consistent with thyroiditis. Fine needle aspiration (FNA) cytology of thyroid revealed acid fast bacilli and an acute inflammatory infiltrate. HIV antibody was negative. TSH receptor and thyroid peroxidase antibodies were negative. Hyperthyroidism was diagnosed on thyroid function tests, which showed a fully suppressed TSH at <0.01 mU/l and an elevated total thyroxine at 165 nmol/l and free thyroxine level at 35 pmol/l. A diagnosis of tuberculous thyroiditis causing hyperthyroidism was made and treatment with anti-tuberculosis therapy, isoniazid, pyrazinamide, rifampicin and ethambutol and anti-thyroid therapy, carbimazole, was initiated. Six months after presentation, the patient was well and off all treatment and the goitre was all but gone.

Discussion There is a precedent for chronic inflammatory thyroiditis due to Hashimoto's disease (so called Hashitoxicosis). This patient had tuberculous thyroiditis and thyrotoxicosis with a goitre which resolved with therapy. We suggest the tuberculous thyroiditis caused release of preformed thyroid hormone for a limited period of time sufficient to cause thyrotoxicosis.