Acute Respiratory Distress Syndrome and Pneumonia: A Comprehensive Review of Clinical Data

Abstract

Acute respiratory distress syndrome (ARDS) and pneumonia are closely correlated in the critically ill patient. Whereas ARDS is often complicated by nosocomial pneumonia, pulmonary infection is also the most frequent single cause of ARDS. The prevalence of pneumonia during the course of ARDS seems to be particularly high, but whether persons with ARDS are more susceptible to pneumonia or simply have more risk factors remains unknown because of methodological limitations. Recent research suggests that host factors have a major bearing on the development of ARDS. To date, sepsis seems to be the principal link between pneumonia and ARDS. However, prospective observational data on this supposed sequence are not available. The individual role of specific pathogens for the development of ARDS is difficult to assess, because prospective studies are missing. Respiratory viruses have received particular attention, but this review suggests that infections with coronavirus and avian influenza virus (H5N1) are associated with a high incidence of ARDS.

Hyperinduction of Cyclooxygenase‐2–Mediated Proinflammatory Cascade: A Mechanism for the Pathogenesis of Avian Influenza H5N1 Infection

“…Such responses may be protective at the level of activation observed with H1N1 infection, but the much greater proinflammatory activity seen during H5N1 infection could well have pathological consequences, such as ARDS, and it may explain the high mortality rate that is frequently associated with human H5N1 infection [3,23]. It is accepted that the hyperinduction of cytokines contributes to the pathophysiology of ARDS in sepsis [24,25].…”

Anti-malaria drug chloroquine is highly effective in treating avian influenza A H5N1 virus infection in an animal model

“…Previous reports have demonstrated that the high mortality in humans infected with avian influenza A H5N1 is partly due to acute lung injury or the resulting severe condition, acute respiratory distress syndrome (ARDS) [4,5]. There are few treatment choices for ARDS, aside from mechanical supporting equipment and empirical treatments.…”

Knockdown of lung phosphodiesterase 2A attenuates alveolar inflammation and protein leak in a two-hit mouse model of acute lung injury

“…ARDS is characterized by neutrophil infiltration, the generation of toxic cytokines and reactive oxygen species (ROS), increased NO production and the loss of endothelial and epithelial barrier function (4). These features can be reproduced in animal models by the installation of intratracheal (IT) LPS (10,24,31), a key component of the gram-negative bacterial cell wall.…”