Assessment of Predictors for Severity in Scrub Typhus-A Case-Control Study

ABSTRACT

Objective: Scrub typhus is a rickettsial febrile condition caused by bacteria called Orientia tsusugamushi. It spreads to people through bites of infected larval mites. The objective of this study was to predict the severity of scrub typhus. Methods: A case-control study was done at Kasturba Medical College Hospital (2012-2015) retrospectively on patients admitted with scrub typhus. Patient demographics, lab parameters, investigations and treatment courses were noted. Subjects were divided into two groups, non-severe and severe group. Patient clinical details and laboratory parameters were compared in both the groups. The lab parameters associated with the severity of disease and mortality were also analyzed. A total of 210 patients out of which 140 controls (non-severe group) and 70 were cases (severe group). Results: The overall mortality due to scrub typhus infection was 14.3%. Eschar was present in 21.4% of the patients. Among the cases, the common symptoms were cough, chest pain, abdominal pain and distension, pedal edema and facial puffiness. Lymphadenopathy was observed with non-severe cases of scrub typhus and was statistically significant whereas, icterus, maculopapular rash, and hepatomegaly were associated with severe scrub typhus infection. Hemoglobin, platelet count and serum albumin were considerably lower in patients who died, whereas AST, aPTT, serum urea and creatinine were higher in them. Conclusion: Lower levels of hemoglobin, platelet count, serum albumin and higher levels of total leucocyte count, hepatic transaminases and serum creatinine correlated with severity. Doctors need to be watchful for such lab parameters and act quickly.