Definitions of Severe Pneumonia, Risk Factors, and Prognosis
Clinical Features of Pneumonia
Evaluation of Nonresponding Patients
Severe pneumonia can occur in patients with all forms of lung infection, including community-acquired pneumonia (CAP), nosocomial pneumonia, ventilator-associated pneumonia (VAP), and health-care-associated pneumonia. Patients who acquire severe pneumonia often have an excessive immune response to infection that is not localized to the initial site of lung infection. In patients with CAP, early recognition of severe illness can reduce mortality, and delayed transfer to the ICU may be a predictor of poor outcome. Scoring systems such as the Pneumonia Severity Index, CURB-65, and SMART-COP are adjunctive tools that can help identify CAP patients with severe illness. Once recognized, severe pneumonia should be treated promptly, and delays in therapy increase mortality, as does inappropriate therapy, which is more likely to occur when patients are infected with multidrug-resistant (MDR) bacteria. For patients with severe CAP and for those with VAP who are at risk for MDR pathogens, initial therapy should be with a combination of agents. In severe CAP, combination therapy provides coverage of multiple organisms, including atypical pathogens. In VAP, combination therapy increases the likelihood of covering MDR pathogens and can provide coverage for mixed infection involving gram-negatives and methicillin-resistant Staphylococcus aureus. Prevention of severe CAP is focused on smoking cessation and vaccination (pneumococcal and influenza), while VAP prevention involves multiple interventions, often combined into a “ventilator bundle.”Objectives
Define the epidemiology of severe community-acquired pneumonia (CAP), hospital acquired pneumonia (HAP)/ventilator-associated pneumonia (VAP), and health-care-associated pneumonia (HCAP) and risk factors for mortality.
Discuss the common etiologic pathogens and therapy of severe CAP, HAP/VAP, and HCAP, including the impact of atypical pathogens, multidrug-resistant gram-negative, methicillin-resistant Staphylococcus aureus (MRSA), and penicillin-resistant pneumococcus.
Describe the pathogenesis of severe pneumonia.
Outline therapies and prevention strategies for severe pneumonia.