Clinical and laboratory findings associated with severe scrub typhus.
BACKGROUND
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.


METHODS
We 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.


RESULTS
There 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 >or= 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 <or= 3.0 g/dL (OR = 5.01, P = 0.004, CI = 1.69-14.86).


CONCLUSIONS
Our results suggest that clinicians should be aware of the potential for complications, when scrub typhus patients are older (>or= 60 years), presents without eschar, or laboratory findings such as WBC counts > 10, 000/mm3, and serum albumin level <or= 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.
Kim
Dong-Min
DM
Division of Infectious Diseases, Department of Internal Medicine, Chosun University School of Medicine, Gwangju City, Republic of Korea.
Kim
Seok Won
SW
Choi
Seong-Hyung
SH
Yun
Na Ra
NR
D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012285:Orientia tsutsugamushi / Q000302:isolation & purification*; D011446:Prospective Studies; D012307:Risk Factors; D012612:Scrub Typhus / Q000150:complications* / Q000453:epidemiology / Q000473:pathology*