Severe Community-Acquired Pneumonia

Saxena, Puneet; Sehgal, Inderpaul Singh; Agarwal, Ritesh; Dhooria, Sahajal

Community-acquired pneumonia refers to an infection of the lung parenchyma acquired outside a healthcare setting. The term severe CAP (SCAP) signifies a more serious form of community-acquired pneumonia that requires admission to the intensive care unit and has a high risk of mortality. SCAP is an important cause of morbidity and mortality in both the developed and the developing world. The common causative pathogens of SCAP include pneumococcus, Hemophilus influenzae, and atypical bacterial organisms, and less commonly, gram-negative bacilli and Staphylococcus aureus, particularly in hosts with risk factors for these pathogens. An initial diagnosis can usually be made clinically based on the presentation, and confirmed with the help of a chest radiograph. Scoring systems may be used to assess the severity, mortality risk and requirement of admission to the intensive care unit. Empirical antibiotic treatment must be instituted at the earliest after sending blood and respiratory samples for microbiological analysis and antibiotics may be changed according to the results. Supportive and adjunctive treatments are instituted, as required. Personalized management based on various novel strategies may improve the management of SCAP in the future. In this chapter, we present a detailed discussion of the epidemiology, pathogenesis, diagnostic evaluation and treatment of SCAP.