The Increasing Incidence of Empyema

Joaquín Burgos; Vicenç Falcó; Albert Pahissa

Disclosures

Curr Opin Pulm Med. 2013;19(4):350-356. 

In This Article

Abstract and Introduction

Abstract

Purpose of review The aim of this review is to highlight recent changes concerning the incidence of empyema. In this article we have focused on community-acquired empyema

Recent findings The incidence of empyema seems to have been increasing both in children and adults worldwide in the past decades, mainly in healthy young adults and in older patients. The bacteriology of pleural infection is changing as well. In children, the most common microorganism that causes empyema continues to be Streptococcus pneumoniae. Interestingly, the widespread use of the seven valent conjugate vaccine has produced a replacement phenomenon with the emergence of some pneumococcal serotypes such as serotypes 1, 3 and 19A, which have a higher propensity to cause empyema. Moreover increases in the incidence of empyema due to Staphylococcus aureus have also been observed. In adults, increases in the rate of empyema due to Streptococcus milleri group and S. aureus have been reported.

Summary Continued surveillance in the epidemiology of empyema is needed. Progress in new strategies of prevention, such as a new generation of conjugate pneumococcal vaccines and protein-based vaccines, could become an important step in the control of this important complication.

Introduction

Empyema is an ancient disease that continues to be an important clinical problem nowadays. The earliest recorded description of a patient with empyema dates back to more than 5000 years ago in ancient Egypt.[1] Later, the first consistent description of its manifestations and treatment was attempted by Hippocrates over 2000 years ago.[2] However, despite the centuries of learned experience, the appearance of antibiotics and the use of different pneumococcal vaccines, empyema remains the most common complication of pneumonia and an important cause of morbidity worldwide.[3] Nowadays, over 65 000 patients suffer from pleural infection each year in the UK and USA.[4] Approximately 15% of these patients die, and another 30% require surgical drainage of the pleural space.[5,6]

The incidence of pleural infections diminished significantly during the first half of the 20th century.[7,8] In the preantibiotic era, empyema was a complication of approximately 5% of cases of pneumonia, but with the development of antibiotics in the decade of the 1940s the rate of empyema declined to 2%.[3] In an interesting study over four decades, Weese et al.[7] found an incidence of empyema of 79 cases per 100 000 admissions in the preantibiotic era; this rate of incidence dropped to 52 cases per 100 000 by 1947–1948 and remained at about that level through 1967–1969. However, this trend changed at the end of the 20th century and, since the decade of the 1990s the incidence of empyema has tended to be increasing worldwide.

To understand the dynamics in the incidence of empyema, it is important to take into account the complex microbiology of pleural infection. A wide range of microorganisms have been cultured from empyema, and mixed infections do occur. The prevalence of different causative organisms differs depending on the source of infection (community vs. hospital-acquired empyema), the age (children vs. adults) and the host characteristics (immunocompetent vs. immunocompromised patients). In addition, in up to 40% cases of empyema a causal microorganism is not isolated in bacterial cultures.[5,9,10]

The aim of this review is to highlight recent changes concerning the incidence of empyema, with special emphasis on community-acquired empyema. We will also review the possible clinical implications of these changes and discuss the possible causes of this phenomenon.

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