Primary tuberculosis of the thyroid gland: an unexpected cause of thyrotoxicosis

We describe a 38-year-old Indian man who presented with a 2-week history of fever, night sweats and neck swelling who was found to be clinically thyrotoxic with a nodular goitre, tachycardia and high fever. Biochemical investigation revealed hyperthyroidism in association with deranged liver function tests and raised inflammatory markers. Ultrasound and CT scans of the neck revealed multinodular thyroid enlargement. He was considered most likely to have an acute infectious thyroiditis with a differential diagnosis of a toxic multinodular goitre and was started on carbimazole and antibiotics. He underwent fine needle aspiration of the thyroid which revealed necrotic cells and acid-fast bacilli, confirming a diagnosis of primary tuberculosis (TB) of the thyroid gland with no evidence of any other organ involvement on systemic imaging. He was started on TB therapy for 6 months and discharged with outpatient follow-up. Symptoms and biochemical markers subsequently resolved.