Max is a 65-year-old man who presents with a "terrible cough" and fever of several days' duration. He has just returned from a business trip and is feeling quite run down. His cough is productive, with rusty-colored sputum. He is otherwise healthy and is a nonsmoker. His chest x-ray is similar to the one shown in Figure 55-1. He is diagnosed with probable bacterial pneumonia and is placed on antibiotics. You note that he has never had vaccinations against influenza or pneumococcus, and you offer these to him at a follow-up visit when he is well.
Chest x-ray (CXR) showing right upper lobe consolidation. (Reproduced with permission from Miller WT: Diagnostic Thoracic Imaging. New York, NY: McGraw-Hill Education; 2006.)
Pneumonia refers to an infection in the lower respiratory tract (distal airways, alveoli, and interstitium of the lung). Community-acquired pneumonia (CAP) has traditionally referred to pneumonia occurring outside of the hospital setting. More recently, a subgroup of CAP has been identified that is associated with healthcare risk factors (e.g., prior hospitalization, dialysis, nursing home residence, immunocompromised state); this form of pneumonia has been classified as healthcare-associated pneumonia (HCAP), although definitions of HCAP vary. While severity and excess mortality are associated with HCAP, as well as a slight increase in multidrug-resistant (MDR) pathogens, most studies do not support either a causal relationship between MDR and excess mortality or demonstrate benefit from broad-spectrum antibiotic coverage.1 It is likely that excess mortality is a result of underlying patient-related factors (e.g., older age, comorbidities, higher initial severity).1,2 This chapter primarily addresses CAP.
Three to 4 million adults per year in the United States are diagnosed with CAP (8 to 15 per 1000 persons/year).3,4
Annual incidence rate of CAP requiring hospitalization for adults: 24.8 cases (95% confidence interval [CI], 23.5 to 26.1) per 10,000 adults. The incidence rate among adults 65 to 79 years of age was 63.0 cases per 10,000 adults and for those 80 years of age or older was 164.3 cases per 10,000 adults.5
Annual incidence rate of CAP requiring hospitalization for children: 15.7 cases (95% CI, 14.9 to 16.5) per 10,000 children. The highest rate was among children younger than age 2 years (62.2 cases per 10,000 children).6
Of the 10% to 20% of patients with CAP admitted to the hospital,3,4 10% to 20% are admitted to the intensive care unit (ICU).7
Increased incidence in men and in blacks versus whites.3
CAP is the most frequent cause of death caused by infectious disease in the United States and the eighth leading cause of death overall (2014).7,8 Influenza and pneumonia were responsible for 55,227 deaths or 2.1% of the total deaths ...