To analyze the clinical characteristics of severe tsutsugamushi disease, and to improve the ability of clinicians to recognize severe cases.The clinical data of patients with tsutsugamushi disease from January 1st, 2017 to December 31st, 2018 in hospitals of Yunnan Province were retrospectively collected by the Case Report Form (CRF). The age, gender, clinical symptoms at admission; white blood cell (WBC), eosinophil count (EO), red blood cell (RBC), platelet count (PLT), hemoglobin (Hb), hematocrit (HCT), albumin (ALB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), lactate dehydrogenase (LDH), blood urea nitrogen (BUN), serum creatinine (SCr), uric acid (UA) on the first day of admission; and clinical outcomes were recorded. The patients were divided into the non-critical group and the critical group according to the diagnostic criteria, the data of clinical manifestation, laboratory examination, imaging examination and prognosis were compared between the two groups. Multivariate Logistic regression analysis was performed on the variables with statistical significance. The receiver operating characteristic (ROC) curve of LDH and UA for differential diagnosis of severe tsutsugamushi disease were drawn.From January 1st, 2017 to December 31st, 2018, 408 patients with tsutsugamushi disease were enrolled in 37 hospitals in 15 prefectures and municipalities of Yunnan Province. 385 cases were clinically diagnosed and 23 cases were laboratory diagnosed. There were 265 cases in non-critical group and 143 cases in critical group. A total of 8 cases died and the remaining 400 cases were discharged from hospital. (1) Compared with the non-critical group, age of the critical group was older, the incidence of dizziness, cough, expectoration, general soreness, dyspnea, palpitation, abdominal pain, diarrhea, bulbar conjunctival congestion, pleural effusion, peritoneal effusion, pericardial effusion, hepatomegaly, splenomegaly, and the levels of WBC, ALT, AST, LDH, TBil, BUN, SCr, UA were significantly increased, the incidence of lymph node enlargement and the levels of EO, PLT and ALB were significantly decreased, and there was no significant difference in other indicators between the two groups. (2) Multivariate Logistic regression analysis showed that age, dyspnea, palpitations, LDH, UA, ALB were risk factors for severe tsutsugamushi disease, β value was 0.040, -2.147, -1.414, 0.002, 0.005 and -0.132 respectively, and the odds ratio (OR) was 1.041, 0.117, 0.243, 1.002, 1.005 and 0.877 respectively (all P < 0.01). (3) ROC curve analysis showed that UA and LDH had better accuracy in differential diagnosis of severe tsutsugamushi disease (both P < 0.01), and the area under ROC curve (AUC) was 0.693 [95% confidence interval (95%CI) = 0.633-0.754], 0.819 (95%CI = 0.776-0.862), respectively. When the cut-off of UA was 306.2 μmol/L, the sensitivity was 60.8%, and the specificity was 77.4%. When the cut-off of LDH was 485.5 U/L, the sensitivity was 74.8%, and the specificity was 74.7%. The diagnostic value of UA combined with LDH was higher, AUC was 0.832, the sensitivity was 69.9%, and the specificity was 85.3%.Severe tsutsugamushi disease can be diagnosed at an early stage according to age, respiratory distress, palpitations, hypoalbuminemia, UA > 306.2 μmol/L, and LDH > 485.5 U/L.
