Clinical Characteristics And Risk Factors Of Scrub Typhus With Multiple Organ Dysfunction

Background:As a natural foci infectious disease,the morbidity of scrub typhus has been increased rapidly.There is no specificity in clinical features except the presence of eschar that is easily overlooked.Severe scrub typhus may lead to organ dysfunction which is usually caused by the delay of treatment.Mortality rates of severe complicated scrub typhus are estimated to be approximately 24.1%.In this article,we try to identity the risk factors related to multiple organ dysfunction syndrome(MODS).Method:Retrospective data were collected from patients registered at our hospital from 2017 to2020.Patients were classified into two groups(MODS group and non-MODS group).The characteristics related to disease severity were explored and tested with multivariable ordinal continuation ratio logistic regression.Result:A total of 91patients were classified into non-MOD group(n=65)and MODS group(n=26).Patients were higher risk of suffering from scrub typhus during June to August every year(58.2%).One of the most common symptoms was fever and the eschar(84.6%)was the main sign of patients.The most common complications were liver dysfunction(86.8%),pulmonary inflammation(51.6%)and thrombocytopenia(27.5%).All patients were recovery after the main treatment of doxycycline.There were significant differences between two groups in mean arterial pressure(t=2.970,P=0.004),pulse(Z=-3.358,P=0.001),peripheral lymphocyte proportion(Z=-2.266,P=0.023),monocyte proportion(Z=-2.671,P=0.008),hemoglobin(t=2.664,P=0.009),red blood cell count(t=2.664,P=0.009),hematocrit(Z=-2.847,P=0.004),platelet count(Z=-5.096,P<0.001),serum albumin(t=4.130,P<0.001),lactate dehydrogenase(t=-2.935,P=0.004),urea nitrogen(Z=-3.107,P=0.002),creatinine(Z=-3.107,P=0.002),fibrinogen(t=2.655,P=0.010),triglyceride(Z=-2.335,P=0.02),D-dimer(Z=-4.632,P<0.001),procalcitonin(Z=-5.732,P<0.001)and CRP(Z=-3.400,P<0.001).Multivariate analysis demonstrated that the significant associated factors for scrub typhus severity were blood platelet count<100×10~9/L(OR=27.459,95%CI:2.75-274.192,P=0.005),the level of procalcitonin>0.5ug/L(OR=14.341,95%CI:1.438-143.036),serum albumin<30g/L(OR=60.848,95%CI:4.188-884.141,P=0.03).The area under ROC curve was 0.969 and Youden index was 0.809.Conclusion:It is necessary to pay attention to the physical examination of patients with fever of unknown origin to avoid the missed diagnosis.To improve prognosis,We should pay attention to patients with blood platelet count<100×10~9/L,level of procalcitonin>0.5ug/L and serum albumin<30g/L which are related to scrub typhus with MODS.