Differences of clinical manifestations and organ damage between patients with severe fever with thrombocytopenia syndrome and patients with tsutsugamushi disease

Objective To analyze the differences of clinical manifestations and organ damage between patients with severe fever with thrombocytopenia syndrome(SFTS) and patients with tsutsugamushi disease, and to investigate the prognostic factors of SFTS. Methods The research was performed on 49 patients with SFTS and 16 patients with tsutsugamushi disease who visited the First Affiliated Hospital of Anhui Medical University from October 2014 to June 2017. The general information of patients including region, age, gender and clinical manifestations were evaluated. Blood routine, liver and kidney function, myocardial enzyme levels, lipase, amylase, electrolytes, C-reactive protein, procalcitonin, prothrombin time(PT) and activated partial thromboplastin time(APTT) were continuously monitored during the course of disease. T test was used for continuous variables of normal distribution, and non-parametric test was used for variables of non-normal distribution. Chi-square test was used for categorical variables. Results The mean age of SFTS patients was 62.1±15.5(ranging from 17 to 87 years) and the mean age of tsutsugamushi patients was 56.1±9.2 (ranging from 47 to 73 years). There was no significant difference between the two groups (t=1.47, P=0.147). There were 25 males(51%) in SFTS patients and 8 males (50%) in tsutsugamushi disease patients. There was no significant difference between the two groups (χ2=0.005, P=0.943). The incidences of headache, vomiting, superficial lymphadenectasis, disturbance of consciousness, proteinuria, hematuria, pulmonary infection, multiple organ dysfunction and acute pancreatitis in SFTS patients were all significantly higher than those in tsutsugamushi disease patients (χ2=8.82, 4.38, 8.71, 11.17, 7.88, 5.56, 4.35, 9.43, and 8.13, respectively, P<0.05 or 0.01). The counts of leukocytes (Z=2.73), neutrophils (Z=2.46), lymphocytes (Z=3.15), platelets (Z=4.25), albumin (Z=2.65) and sodium ion (t=2.10) in SFTS patients were all significantly lower than those in patients with tsutsugamushi disease (P<0.05 or 0.01). The levels of aspartate aminotransferase (Z=2.94), lactate dehydrogenase (Z=3.42), creatine kinase(CK)(Z=2.88), amylase (Z=2.77), lipase (Z=2.82), creatinine (Z=2.07) and urea nitrogen (Z=2.50) in fatal SFTS patients were all significantly higher than those in patients with tsutsugamushi disease (P<0.05 or 0.01). Among 49 SFTS patients, 16 patients died and 33 patients recovered finally. The age(t=3.33), platelet count (Z=2.55), alanine aminotransferase (ALT)(Z=2.10), aspartate aminotransferase (AST)(Z=2.22), lactate dehydrogenase (Z=2.26), CK(Z=3.50), CK-MB (Z=3.10), creatinine (Z=2.17), urea nitrogen (Z=2.36), and sodium (t=2.65) between the two subgroups had significant differences (P<0.05 or 0.01). Conclusions SFTS is more severe and has high mortality, while tsutsugamushi disease has a better prognosis. Early differential diagnosis and early rational treatment are important to reduce the mortality of patients with SFTS. Key words: Scrub typhus; Severe fever with thrombocytopenia syndrome; New bunyavirus; Organ damage