Endocrine Abstracts

Introduction: A diagnosis of subacute thyroiditis (SAT) is readily suspected when patients present with a particular set of typical clinical and laboratory characteristics. We present a patient with atypical SAT who had no neck pain but presented with fever, and weight loss; had thyrotoxicosis with normal 99mTc uptake, and needed higher doses of steroids to resolve.

Case report: A 57-year-old man presented with a fever (39  °C) of 2 month-duration. Physical examination was unremarkable. Laboratory analysis revealed WBC: 10 550 K/ul, hemoglobin: 10 g/dl, erythrocyte sedimentation rate: 102 mm/h, C-reactive protein: 17 (<0.5) and normal renal, hepatic function tests. Hepatitis and human immunodeficiency virus serologies were negative. Toxoplasmosis, Epstein-Barr virus, and cytomegalovirus IgM and IgG titers were negative. Blood and urine cultures were also negative. Serum protein electrophoresis showed no abnormality compatible with multiple myeloma. Computed tomography of the neck, thorax and abdomen showed jugular, mediastinal, parailiac and retroperitoneal lymph nodes in nonpathological size. Biopsy of a lymph node showed lymphoid hyperplasia. Transthoracic echocardiography did not show any finding compatible with infective endocarditis. TSH: 0.412 IU/ml (0.2–4.2), fT₃: 14 pg/ml (2.8–4.3), fT₄: 0.9 ng/dl (1.04–1.65), anti-TPO: 16 (0–34), anti-TG: 32 IU/ml (0–115), TSH receptor antibody: 0.4 U/l (<1.8), thyroglobulin: 14 ng/ml (0.83–68). Thyroid ultrasonography did not show any nodules. Thyroid scintigraphy showed normo-active, diffuse hyperplastic thyroid gland. Methimazole and propranolol were initiated. But his fever did not resolve until 60 mg of methylprednisolone was given with the diagnosis of SAT. After steroid treatment, fT₃ levels decreased which had increased previously with methimazol.

Conclusion: This case presented atypically in that he had no neck pain but was diagnosed with SAT while being worked up for the fever of unknown origin. Interestingly, he had normo-active thyroid gland and his fT₃ levels increased to very high levels in disproportion to his fT₄ levels. Higher doses of steroids were needed to resolve his fever and normalize his fT₃ levels. This report illustrates that the diagnosis and treatment of SAT can sometimes be difficult.