Subacute thyroiditis mimicking tuberculosis and lymphoma: case report and literature review.

Abstract Patient: Male, 41 Final diagnosis: Sub-acute thyroiditis Symptoms: fever, night sweats and weight loss Medication: aspirin, prednisolone Clinical Procedure: - Specialty: Endocrinology, Infectious Disease, Otolaryngology Objective: Rare disease, challenging diagnosis Background: Sub-acute thyroiditis (SAT) is a self-limiting condition caused by thyroid inflammation. It usually presents with fever, neck pain and symptoms of thyrotoxicosis. Atypical presentations without neck pain are rare and often lead to misdiagnosis. Case Report: We report a case of atypical SAT that was initially misdiagnosed as lymphoma, with tuberculosis, painless sporadic thyroiditis and laryngeal malignancy being differentials. The patient, a 41-year-old male, presented with progressively worsening fevers, night sweats and weight loss, with thyroid cartilage thickening and tenderness on physical exam. He was diagnosed with SAT through Doppler ultrasound scanning of the thyroid gland, elevated inflammatory markers and the presence of antibody-negative hyperthyroidism on his biochemical thyroid screen. Symptomatic relief was provided with salicylate and prednisolone. The patient experienced transient asymptomatic hypothyroidism four months after disease onset which was not treated. Euthyroidism was achieved six months after symptom onset. Conclusions: SAT is a rare disease thought to be post-viral in origin. It generally presents with fever, neck pain and signs of thyrotoxicosis, and evolves in three phases- a hyperthyroid, hypothyroid and euthyroid phase. Atypical SAT without neck pain is even rarer, so clinicians should maintain a high index of suspicion for thyroid disorders whenever symptoms suggestive of thyrotoxicosis are encountered.