Unmasking Subacute Thyroiditis in a Young Male with PUO: A Case Report
Abstract
Pyrexia of unknown origin (PUO) poses a diagnostic challenge, defined as persistent fever exceeding 38.3°C (100°F) without an identified cause after extensive investigation. Subacute thyroiditis (SAT), an uncommon inflammatory condition of the thyroid gland, typically presents with neck pain, thyrotoxic symptoms, and elevated inflammatory markers. However, it rarely manifests as PUO without typical symptoms. We report a case of a 32-year-old Indian male presenting with a 20-day history of persistent fever without localized symptoms, initially treated empirically with antibiotics without improvement. Clinical examination revealed a firm, non-tender goiter, and laboratory investigations showed elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Subsequent thyroid function tests indicated elevated free T4 levels with low TSH, suggestive of thyroiditis, after negative thyroid autoantibodies ruling out Graves' disease. Further investigations including imaging and tests for PUO were negative, prompting an empirical trial of steroid therapy which resulted in rapid clinical improvement. Subsequent thyroid function tests revealed transient hypothyroidism, resolving without intervention. Retrospectively, a diagnosis of subacute thyroiditis was established, highlighting its atypical presentation as PUO. Our case sheds light on the importance of considering uncommon thyroid pathologies in the differential diagnosis of PUO, especially when typical symptoms are absent.
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DOI: http://dx.doi.org/10.52155/ijpsat.v45.2.6476
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