Clinico-epidemiological and laboratory profiles of scrub typhus in a tertiary care hospital in eastern India: an observational study

Abstract Background: Scrub typhus is an acute febrile illness that resembles other common febrile conditions such as leptospirosis, typhoid fever, malaria, and dengue. Recognizing its varied clinical manifestations, understanding associated epidemiological factors, and monitoring laboratory parameter changes are crucial for early differentiation from these disorders. Timely initiation of treatment with doxycycline ensures complete recovery from scrub typhus. Materials and Methods: This observational cross-sectional study was conducted in the Department of Tropical Medicine, Kolkata, West Bengal, India on patients with a history of fever lasting more than 5 days, with or without rash and eschar, and confirmed positive for scrub typhus immunoglobulin M through enzyme-linked immunosorbent assay. The study included 30 patients aged over 12 years who were admitted to the School of Tropical Medicine, Kolkata, West Bengal, India. Results: Most of the study population was between 21 and 50 years old, with females constituting 63.3% of cases. Rural residents accounted for 70% of the patients. The mean duration of fever at admission was 8.33 ± 1.58 days. The shock was observed in 16.7% of patients, of whom 40% responded to fluid therapy alone, whereas 60% required vasopressor support. Typically, shock develops around the eighth to ninth day of illness. Moderate pallor was seen in 90% of patients, and edema occurred in 16.7%. In 36.7% of patients, eschars were present, whereas 43.3% exhibited rashes. Lymphadenopathy was noted in 63.3%, and hepatosplenomegaly was identified in 56.7% of cases as mild and 23.3% as moderate—additionally, 6.7% of patients presented with ascites. Laboratory findings revealed leukocytosis in 60% of patients, thrombocytopenia in 6.7%, and an abnormal international normalized ratio in 6.7%. Elevated liver enzymes were detected in 50% of patients, whereas chest X-rays showed pneumonitis changes in the bilateral lower zones in 60%. Acute kidney injury (AKI) and acute meningoencephalitis were observed in 6.7% and 13.3% of patients, respectively. Doxycycline therapy elicited a positive response in 60% of patients within 48 h, whereas the remaining patients experienced a delayed response. Conclusion: Scrub typhus is a significant cause of acute febrile illness with potential complications, including shock, pneumonitis, meningoencephalitis, and AKI. Clinical features such as eschars and rashes are pivotal for suspicion. Prompt diagnosis and treatment with doxycycline can significantly reduce morbidity and save lives.