Abstract
A 67-year-old man was admitted to our hospital with a high fever. Laboratory tests revealed leukopenia, thrombocytopenia, liver dysfunction, rhabdomyolysis, and hyperferritinemia. He was diagnosed with severe fever with thrombocytopenia syndrome (SFTS) complicated by hemophagocytic lymphohistiocytosis and treated with steroid therapy, intravenous calcium channel blocker (CCB), and supportive care, without favipiravir. Serum levels of ferritin and soluble interleukin 2 receptor (sIL2R) were markedly elevated on Day 3 after admission and decreased thereafter, while an SFTS viral load of 6.8×10(4) copies/μL was detected on Day 2, increasing to 2.9×10(5) copies/μL on Day 6. Serum ferritin and sIL2R levels may be better indicators of mortality than the SFTS viral load, and CCBs may have a therapeutic effect.