Department of Internal Medicine, Ako City Hospital, Ako, Hyogo, Japan
Integrated Clinical Education Center, Kyoto University Hospital, Kyoto, Japan.
BMJ Case Rep. 2020 Oct 8;13(10):e235447. doi: 10.1136/bcr-2020-235447.
Severe fever with thrombocytopenia syndrome (SFTS) is caused by infection with SFTS virus and this mortality rate is 16.2% to 30%. An 85-year-old male patient presented to the emergency department of the hospital with primary complaints of fever and consciousness disturbance. Haemophagocytic syndrome and prolonged activated partial thromboplastin time (APTT) without associated prolonged prothrombin time were observed, suggesting SFTS, which was eventually diagnosed. APTT-only prolongation has been reported previously with SFTS, but the mechanism is unknown. The absence of coagulation factors was determined by a cross-mixing study. In addition, examination of intrinsic coagulation factors showed reduced factor XI activity. These results suggest that factor XI is causally related to APTT-only prolongation in SFTS.
严重发热伴血小板减少综合征（SFTS）由感染 SFTS 病毒引起，死亡率为 16.2%至 30%。一名 85 岁男性患者因发热和意识障碍到医院急诊科就诊。观察到噬血细胞综合征和延长的部分活化凝血活酶时间（APTT），而凝血酶原时间无延长，提示为 SFTS，最终确诊。先前曾有报道 SFTS 仅出现 APTT 延长，但机制不明。通过交叉混合研究确定不存在凝血因子。此外，内源性凝血因子检查显示因子 XI 活性降低。这些结果表明，因子 XI 与 SFTS 中仅 APTT 延长存在因果关系。
