A comparative study of clinical and laboratory profiles of scrub typhus in different age groups: our experience

Aim of the study
Rickettsial infections rate as the second most frequently reported infections for non-malarial febrile illnesses in South East Asia, after dengue. Scrub typhus is an acute infectious disease caused by Orientia tsutsugamushi, which is categorised in the Rickettsia genus.

Material and methods
This prospective study was carried out from July 2015 to June 2016 in the Department of Paediatric and Internal Medicine after obtaining institutional ethical clearance. A thorough history, meticulous physical examination, course of the hospital stay, complications, and outcomes were properly documented. Basic laboratory studies with additional investigations were performed. Serum IgM ELISA for scrub typhus was performed in all suspected cases and an optical density (OD) greater than 0.5 was considered to be positive.

Results
Scrub typhus was diagnosed in 106 cases (IgM ELISA positive) during the study period; 48 (45%) were in the paediatric age group (≤ 14 years) and 58 were adults. Gastrointestinal symptoms, hepatomegaly, and lymphadenopathy were more frequent in the paediatric age group than in adults (p ≤ 0.05). Eschar was found in 28.3% of cases, but there was no significant difference between paediatric and adult populations. Encephalopathy was more common in children, but other organ dysfunctions like myocarditis, renal failure, and sepsis were more common in adults (p ≤ 0.05).

Conclusions
Scrub typhus is seen equally in children and in adults. Clinically GI symptoms and encephalopathy are more common in children, whereas other organ dysfunctions are more common in adults. Larger multicentric studies are required to confirm our findings.