Journal Article

Severe fever with thrombocytopenia syndrome: comparison with scrub typhus and clinical diagnostic prediction

Moon, Chisook, Jeong, Hye Won, Kim, Eu Suk, Oh, Myoung-don, Jang, Hee-Chang, Kim, Young Keun, Park, Sang-Won, Jun, Jae-Bum, Lee, Jae Hoon, Jung, Younghee, Bae, In-Gyu, Hur, Jian, Kim, Jeong-Han, Kim, Yeon-Sook, Lee, Chang-Seop, Park, Wan Beom, Ryu, Seong Yeol, Song, Kyoung-Ho, Kwak, Yee Gyung, Chang, Hyun-Ha, Hwang, Jeong-Hwan, Kim, Baek-Nam

2019

Overview

Background Severe fever with thrombocytopenia syndrome (SFTS) is emerging in Asian 3 countries, China, Japan and Korea, which are scrub typhus endemic areas, and its incidence is increasing. As the two infections overlap epidemiologically and clinically and the accessibility or sensitivity of diagnostic tests is limited, early clinical prediction may be useful for diagnostic and therapeutic purposes. Methods Patients aged ≥16 years who were clinically suspected and laboratory-confirmed to be infected with Orientia tsutsugamushi or the SFTS virus in South Korea were enrolled. Clinical and laboratory parameters were compared. Scrub typhus was further subclassified according to the status of eschar and skin rash. An SFTS prediction scoring tool was generated based on a logistic regression analysis of SFTS compared with scrub typhus. Results The analysis was performed on 255 patients with scrub typhus and 107 patients with SFTS. At initial presentation, subjective symptoms except for gastrointestinal symptoms, were more prominent in scrub typhus patients. In addition to the characteristic eschar and skin rash, headache was significantly more prominent in scrub typhus, while laboratory abnormalities were more prominent in SFTS. Leukopenia (white blood cell count < 4000/mm 3 ; odds ratio [OR] 30.13), thrombocytopenia (platelet count < 80,000 /mm 3 ; OR 19.73) and low C-reactive protein (< 1 mg/dL; OR 67.46) were consistent risk factors for SFTS (all P  < 0.001). A prediction score was generated using these 3 variables, and a score ≥ 2 had a sensitivity of 93.1% (95% confidence interval [CI], 87.9–96.4%) and a specificity of 96.1% (95% CI, 93.8–97.6%) for SFTS. Conclusion This prediction scoring tool may be useful for differentiating SFTS from eschar- or skin rash-negative scrub typhus. It is a simple and readily applicable tool with potential for use in primary care settings.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: C-reactive protein / Comparative analysis / Diagnosis / Diagnostic equipment (Medical) / Headache / Infection / Infectious Diseases / Internal Medicine / Korea / Logistic regression / Medical Microbiology / Medical tests / Medicine / Medicine & Public Health / Parasitology / Platelet function disorders / Prediction / Primary health care / Rash / Regression analysis / Research Article / Scrub typhus / Severe fever with thrombocytopenia syndrome / SFTS / Skin / Skin diseases / Thrombocytopenia / Tropical Medicine / Tsutsugamushi / Typhus / Viral diseases / White blood cell count