Predictors of Severity in Scrub Typhus

Abstract

Aims: To study predictors of severity in patients of scrub typhus admitted in a tertiary care hospital.

Material and methods: Total 92 patients of scrub typhus were included in the study. The diagnosis was established by presence of IgM antibodies by Indirect Immunofluorescence Assay (IFA) test which is currently the reference standard for the diagnosis of scrub typhus. The clinical and laboratory profile, course in hospital, and outcome were documented. Factors associated with severe disease were analyzed.

Observations: Fever (100%), cough (37%), headache (33%), vomiting (31%), altered sensorium (23%), diarrhea (18%), abdominal pain (16%), myalgia (14%), and seizures (3%) were common clinical features. An eschar was present in 23% of patients. Common laboratory findings included elevated transaminases (61%), thrombocytopenia (39%), and leukocytosis (30%). Severe sepsis was present in 33% patients. Septic shock was present in 4% patients. Presence of one or more organ failure was seen in 34% of patients. The overall case-fatality rate was 4%. Factors significantly associated with organ failure (severe disease) were leucocytosis (p < 0.001), hyperbilirubinemia (p < 0.001), high SGOT levels (p 0.030), hypoalbuminemia (p < 0.001), high urea levels (p < 0.001), and high creatinine levels (p 0.012). Among the criteria used to classify severity of scrub typhus, presence of one or more organ failure was significantly associated with mortality (p 0.004).

Conclusion: Scrub typhus can manifest with potentially life-threatening complications such as meningoencephalitis, septic shock, ARDS, acute liver failure, acute kidney injury, severe thrombocytopenia. Leukocytosis, hyperbilirubinemia, transaminitis, hypoalbuminemia, and uremia were associated with organ failure and were significantly associated with morbidity and mortality.