Scrub typhus in the Himalayan ranges and sub-Himalayan plains: Recognising an expanding clinical syndrome

Background: Scrub typhus, a rickettsial zoonosis, is endemic in the Indian sub-continent but is rare in the Himalayan region due to natural geographic barriers to both organism and vector. Aims: To study the clinical profile of scrub typhus cases admitted in a tertiary care center. Patients and Methods: We did a retrospective observational study of the positive cases from July 2018 to June 2019 in a tertiary care center. All possible risk factors, demographic details, clinical presentations, laboratory parameters, treatment, and outcomes were analyzed. Results: A total of 80 cases were analyzed. The maximum number of cases was observed in September. Major symptoms noted were fever, abdominal pain, headache, cough, breathlessness, and myalgia. Atypical presentations including capillary syndrome and demyelinating polyneuropathy were observed. The eschar detection rate was low. Among organ involvement, hematology system (70%) was most commonly involved followed by liver, kidney, brain, lungs, and heart respectively. The case fatality rate was 6.82%. Himalayan and non-Himalayan cohorts (n = 32 vs 48 respectively) did not show any statistically significant differences in clinical profile, although one could observe that Himalayan cohorts had higher incidences of leukopenia, splenomegaly, and myocarditis, while fever for >7days at admission, hepatomegaly, acute respiratory distress syndrome, major organ involvement resulting admission in high dependency unit (HDU), and mortality were higher in non-Himalayan cohorts. Conclusion: The current study reveals few atypical presentations and complications differing from the classical scrub typhus. Raised ALP is noticed in majority of cases which can be established as a diagnostic marker in acute undifferentiated febrile illnesses in further study. The presence of leukocytosis has high predictive association with major organ involvement and complications.