Chapter 37: Complicated Pneumonia

DEFINITIONS AND EPIDEMIOLOGY

The term complicated pneumonia in this chapter will refer to pneumonia complicated by the accumulation of fluid or purulent material in the pleural space; this term includes parapneumonic effusions and empyema. The frequency of complicated pneumonia among all children with community-acquired pneumonia (CAP) is not known. Complicated pneumonia has been reported to occur in 6–8% of children hospitalized with CAP.^1,2 In the Centers for Disease Control and Prevention (CDC) Etiology of Pneumonia in the Community study, complicated pneumonia was reported in 4% of children hospitalized with CAP from 2010 through 2012.³

Streptococcus pneumoniae and Staphylococcus aureus remain the most common bacterial causes of complicated pneumonia (Table 37-1), although the epidemiology of complicated pneumonia appears to be changing. In February 2000, the Food and Drug Administration licensed a heptavalent pneumococcal conjugate vaccine (PCV7), which was subsequently recommended by the Advisory Committee on Immunization Practices and the American Academy of Pediatrics for use in children aged ≤2 years as well as in older, high-risk children in the United States.⁴ PCV7 uptake was rapid, and substantial declines in rates of invasive pneumococcal disease (IPD) including CAP were documented in children.^1,5,6 Post-PCV7 licensure studies revealed increases in nasopharyngeal carriage and IPD caused by non-PCV7 serotypes.^7–9 However, in the United States and other regions of the world where PCV7 was used, hospital admissions of children with complicated pneumonia increased.^10–15 Pneumococcal serotypes associated with the increase in parapneumonic effusion and empyema with PCV7 were serotypes 1, 3, 7F, and 19A.^16–19

In February 2010, a 13-valent pneumococcal conjugate vaccine [PCV13 (Prevnar 13, Wyeth Pharmaceuticals Inc., a subsidiary of Pfizer Inc.)] replaced PCV7 in the United States. PCV13 was recommended for children 5 years and younger, and for children younger than 6 years who have underlying medical conditions that increase the risk of pneumococcal disease or complications.²⁰ Similar to observations noted with PCV7, nasopharyngeal carriage by non-PCV13 serotypes increased with the transition to PCV13.^21–24 The incidence of IPD in children and adults decreased with PCV13.^25,26 Moore et al, using laboratory- and population-based data from the CDC’s Active Bacterial Core surveillance, reported a 64% decline in IPD in children younger than 5 years, primarily from a 93% decline in serotypes added to PCV13 by 2012/3 when compared with the period 2004–2010.²⁶ Overall, there were declines in bacteremia, meningitis, and pneumonia in both children and adults with PCV13 in the United States.^26...