Scrub typhus: pathophysiology, clinical manifestations and prognosis

Abstract

Scrub typhus is a zoonosis caused by the pathogen Orientia tsutsugamushi (O. tsutsugamushi). The disease has significant prevalence in eastern and Southeast Asia. Usually presenting as an acute febrile illness, the diagnosis is often missed because of similarities with other tropical febrile infections. Many unusual manifestations are present, and these are described in this review, together with an outline of current knowledge of pathophysiology. Awareness of these unusual clinical manifestations will help the clinician to arrive at an early diagnosis, resulting in early administration of appropriate antibiotics. Prognostic indicators for severe disease have not yet been clearly established.

Scrub Typhus in Northeastern Thailand: Eschar Distribution, Abnormal Electrocardiographic Findings, and Predictors of Fatal Outcome

“…21 Six of nine fatal cases (66.7%) developed severe disease within the first week of illness, in contrast with literature reporting that complications usually appear after the second week. 3 Sonthayanon and others demonstrated AKI = acute kidney injury; ALT = alanine aminotransferase; ARDS = acute respiratory distress syndrome; AST = aspartate aminotransferase; ATB = antibiotic; CXR = chest X-ray; HR = heart rate; RR = respiratory rate.…”

“…1 Presence of an eschar is a useful sign for diagnosing scrub typhus infection. Complications usually develop after the second week of illness, particularly in untreated cases, with systemic involvement 3 and disseminated vasculitis, 4 including septic shock, 5 acute respiratory distress syndrome (ARDS), 6,7 pneumonitis, 7 acute renal failure (ARF), 8,9 meningitis or meningoencephalitis, 10 myocarditis, 11 disseminated intravascular coagulation (DIC), 12 upper gastrointestinal bleeding, 13 and multiorgan dysfunctions (MODS). 1,4 Myocarditis is a rare complication, few reports showed abnormal electrocardiographic (ECG) findings in scrub typhus patients.…”

“…Serology is the mainstay for diagnosing scrub typhus. 2 Patient outcome varies depending on pathogen factors (strain virulence 14 and high bacterial load 15 ), severity of the disease, 16 time to diagnosis, 17 commencement of appropriate treatment, 3 and the presence of drug resistance. 18 This study aims to demonstrate the clinical and laboratory manifestation, particularly eschar distribution and abnormal ECG findings, and the predictors of fatal outcome in scrub typhus patients.…”

Scrub Typhus Meningoencephalitis

“…Eschar is found in 7-80% patients of scrub typhus [3]. In the authors study, eschar was detected in 28.81% of the patients of scrub typhus and 30.77% patients of meningoencephalitis due to scrub typhus [6].…”

“…The pathogen can down-regulate the expression of glycoprotein 96, in infected macrophages and endothelial cells and thereby neutralize host immune response. This molecule plays a central role antigen presentation and antibody production [3].…”