Clinical and laboratory findings associated with severe scrub typhus

Dong-Min Kim,Seok Won Kim,Na Ra Yun,Seong-Hyung Choi

doi:10.1186/1471-2334-10-108

Abstract

BackgroundScrub typhus is a mite-borne bacterial infection of humans caused by Orientia tsutsugamushi that causes a generalized vasculitis that may involve the tissues of any organ system. The aim of this study was to identify factors associated to severe complications from scrub typhus.MethodsWe conducted this prospective, case-control study on scrub typhus patients who presented to the Department of Internal Medicine at Chosun University Hospital between September, 2004 and December, 2006. Cases were 89 scrub typhus patients with severe complications and controls were 119 scrub typhus patients without severe complications.ResultsThere were significant differences in the absence of eschar, white blood cell (WBC) counts, hemoglobin, albumin, serum creatinine, fibrinogen, C-reactive protein (CRP), and active partial thromboplastin time (aPTT) between the two groups. Multivariate analysis demonstrated that only the following four factors were significantly associated with the severe complications of scrub typhus: (1) age ≥ 60 years (odd ratio [OR] = 3.13, P = 0.002, confidence interval [CI] = 1.53-6.41), (2) the absence of eschar (OR = 6.62, P = 0.03, CI = 1.22-35.8, (3) WBC counts > 10, 000/mm3 (OR = 3.6, P = 0.001, CI = 1.65-7.89), and (4) albumin ≤ 3.0 g/dL (OR = 5.01, P = 0.004, CI = 1.69-14.86).ConclusionsOur results suggest that clinicians should be aware of the potential for complications, when scrub typhus patients are older (≥ 60 years), presents without eschar, or laboratory findings such as WBC counts > 10, 000/mm3, and serum albumin level ≤ 3.0 g/dL. Close observation and intensive care for scrub typhus patients with the potential for complications may prevent serious complications with subsequent reduction in its mortality rate.

Highlights

Scrub typhus is a mite-borne bacterial infection of humans caused by Orientia tsutsugamushi that leads to generalized vasculitis which may involve the tissues of any organ systems [1,2]
The diagnosis of scrub typhus was confirmed when an indirect immunofluorescent antibody assay (IFA) IgM titer against O. tsutsugamushi increased to ≥ 1:80 or an IFA titer against O. tsutsugamushi increased four times or more [9]
Severe scrub typhus was defined if it showed the following conditions: (1) pneumonia that revealed parenchymal lung lesions on chest radiographs and cough or dyspnea, (2) renal failure that revealed estimated creatinine clearance less than 50 using the Cockcroft-Gault formula [10], (3) meningoencephalitis that exhibited altered mental states such as confusion, obtundation, stupor, or coma without evident causes such as shock or hypoglycemia, or the presence of both severe headaches and neck stiffness, or cerebrospinal fluid (CSF) counts of ≥ 5 leukocytes/mm3, (4) shock, which is defined by a systolic blood pressure less than 90 mmHg, (5) myocarditis, (6) GI bleeding, or (7) death

Summary

Introduction

Scrub typhus is a mite-borne bacterial infection of humans caused by Orientia tsutsugamushi that causes a generalized vasculitis that may involve the tissues of any organ system. The aim of this study was to identify factors associated to severe complications from scrub typhus. Scrub typhus is a mite-borne bacterial infection of humans caused by Orientia tsutsugamushi that leads to generalized vasculitis which may involve the tissues of any organ systems [1,2]. Reported severe clinical manifestations or complications of scrub typhus include interstitial pneumonia, acute renal failure, meningoencephalitis, gastrointestinal bleeding, and multiple organ failures. Since patients with scrub typhus may die from such complications, we should pay close attention to this disease entity [3,4,5,6]. Most patients with scrub typhus can recover without specific complications with early diagnosis and management. BioMed Central tribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

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