A Continuum of Disease from Community-Acquired Pneumonia to Multiple Organ Dysfunction Syndrome

Community-acquired pneumonia (CAP) is one of the primary causes of sepsis, septic shock, acute respiratory distress syndrome (ARDS), and multiple organ dysfunction syndrome (MODS) [1-3]. The chain of immune responses in patients with pneumonia can be considered as a continuum of disease from an initial appropriate response in patients with CAP, to a deleterious response that encompasses Severe CAP, Sepsis, Septic Shock, ARDS and MODS. As the lung infection overwhelms the natural defenses that are produced by physiologic pulmonary and systemic inflammation, a deeper line of defense is necessary. At this point, the immune system may develop an inflammatory response that may be damaging to vital organs, culminating with organ failure. In this opinion piece I will review the pathophysiology of CAP and construct a continuum of disease from CAP to MODS.