Acute respiratory distress syndrome associated with scrub typhus: Diffuse alveolar damage without pulmonary vasculitis

Pathologic findings of scrub typhus have been characterized by vasculitis o f the microvasculature of the involved organ resulting from a direct invasi on by Orientia tsutsugamushi. We experienced a case of acute respiratory di stress syndrome (ARDS) associated with scrub typhus. The case was proven by eschar and high titer of serum IgM antibody (positive at 1:1280). Open lun g biopsy showed diffuse alveolar damage (DAD) in the organizing stage witho ut evidence of vasculitis. Immunofluorescent antibody staining and polymera se chain reaction for O. tsutsugamushi failed to demonstrate the organism i n the lung tissue. The patient expired due to progressive respiratory failu re despite doxycycline therapy. Immunologic mechanism, without direct invas ion of the organism, may participate in the pathogenesis of ARDS associated with scrub typhus.