Acute suppurative thyroiditis (AST) is a rare inflammatory disease. The rarity of this disease can be attributed to several factors. The thyroid is well encapsulated, which may hinder the transmission of infection from surrounding tissue to the thyroid. In addition, a rich blood supply and lymphatic drainage within the thyroid may be protective against bacterial infection. Furthermore, high iodine(Drug information on iodine) levels within the thyroid gland may create an environment that is unfavorable to bacterial growth.1 Reports of AST are uncommon in patients who have hematological malignancy. Only 9 cases have been reported in the literature.2,3
A 27-year-old man presented to our hospital with symptoms of general weakness and fatigue. His blood test results were positive for anemia (hemoglobin level, 2.9 g/dL). A bone marrow biopsy specimen showed cellularity values of 0% to 10%, a range that is considered hypocellular for the patient's age; erythropoiesis, granulopoiesis, and megakaryocyte production were decreased. Aplastic anemia was diagnosed, and the patient was treated with a consecutive 5-day regimen of antithymoglobulin (ATG). At the start of chemotherapy, the absolute neutrophil count (ANC) was 1534/mL
Five days after the administration of ATG (day 1), sudden fever and sore throat developed. The patient's temperature was 39.9ºC (103.8ºF). Blood pressure was 110/70 mm Hg, with a pulse rate of 96 beats per minute. Symptoms of influenza were absent, but the patient complained of a sore throat and right-sided neck pain. No skin change or discoloration of the neck area was observed; however, swelling and tenderness of the neck developed.
The ANC was 252/mL. Athyroid function test revealed high free thyroxine levels (2.37 ng/dL; normal, 0.70 to 1.80 ng/dL), depressed thyroid- stimulating hormone levels (0.12 mIU/L; normal, 0.4 to 4.1 mIU/L), and normal total triiodothyronine levels (91 ng/dL; normal, 87 to 184 ng/dL). A blood culture was performed, and piperacillin(Drug information on piperacillin) and tobramycin(Drug information on tobramycin) were administered empirically.
Radiological examination revealed cystic lesions of the thyroid gland with decreased enhancement; a thyroid abscess was therefore suspected (day 3; Figure 1). No pyriform sinus fistula (PSF) was detected by laryngoscopy or CT. Because the blood culture grew methicillin-sensitive Staphylococcus aureus (MSSA), cefazolin(Drug information on cefazolin) was added to the therapeutic regimen. Despite this antibiotic therapy and ultrasonography-guided aspiration (day 6; Figures 2 and 3), the patient's condition did not improve. Surgery was performed to manage the thyroid abscess (day 8).