Scrub typhus: Clinical presentation and severity

Background: Scrub typhus is an acute zoonotic febrile illness caused by the obligate intracellular bacteria Orientia tsutsugamushi. In the Indian subcontinent, there has been mounting evidence in the past few years, indicating that it is one of the most prevalent, yet underrecognized entity, probably as a result of its varied presentation, lack of awareness, and hence, a low index of suspicion among clinicians. Materials and Methods: This is a subgroup analysis involving patients diagnosed to have scrub typhus from a large prospective study on patients presenting with acute undifferentiated febrile illness (AUFI) done between October 2012 and September 2013. Results: A total of 452 patients met the eligibility criteria and were included in the final analysis. The mean age of the cohort was 42.7 (standard deviation [SD] 15.1) years and female predominance (266, [58.8%]) was noted. The mean duration of fever was 8.2 (SD 3.2) days. The most common clinical features were chills, generalized myalgia, and breathlessness. A characteristic eschar was noted in 262 (57.9%) patients. Overall, the most common comorbidities were diabetes mellitus, followed by hypertension. Majority of patients were started on doxycycline or azithromycin empirically on clinical suspicion. Among the total study population, 21 (4.6%) patients succumbed to the disease condition and the rest were discharged stable either from the outpatient department or ward. Conclusion: Scrub typhus is one of the most common causes of AUFI in our locality and comprises a third of these cases. The pathognomonic eschar which is present in almost two-third of patients offers a vital clue for the diagnosis of scrub typhus.