Epidemiologia,patogenesis y sintomas de la neumonia

CME Topic

Pneumonia in the Elderly: A Review of the Epidemiology, Pathogenesis, Microbiology, and Clinical Features
Carol P. Chong,
FRACP,

and Philip R. Street,

FRACP

Abstract: Pneumonia is a common and important disease in the elderly. The incidence is expected to rise as the population ages, and, therefore, it will become an increasingly significant problem in hospitals and thecommunity. A comprehensive literature review was performed in order to look at the characteristics of pneumonia in the elderly population. In particular, the epidemiology, etiology and pathogenesis—including risk factors, microbiology, and clinical features—were evaluated. While aging causes physiological changes which make elderly patients more susceptible to pneumonia, it was found thatcomorbidities, rather than age, are also an important risk factor. The most common micro-organism responsible for pneumonia is Streptococcus pneumoniae, but other organisms need to be considered, depending on the environment of presentation. Elderly patients are more likely than younger adults to present with an absence of fever and an altered mental state. Nursing home residents tend to present with moreatypical and less characteristic symptoms. Key Words: clinical features, elderly, microbiology, pathogenesis, pneumonia

This review will focus on the epidemiology, pathogenesis, microbiology, and clinical features of pneumonia. This review defines “elderly” as subjects 65 years or older and “very elderly” as subjects 80 years and older, both reflecting the definitions in most published studies.Epidemiology
The annual incidence of pneumonia in the elderly is between 25 to 44 per a population of 1000 for noninstitutionalized patients and four times that of patients younger than 65.1 For the elderly in residential care, the incidence increases to 33 to 114 cases per a population of 1000 per year.1 Other studies have reported that the rate of pneumonia for those who are in residentialcare facilities is six to ten times higher than elderly who live in the community.1–3 The mortality rate from nursing homeacquired pneumonia is reported to be as high as 44 –57%, whereas mortality rates of community-acquired pneumonia in hospital-based studies are reported to be as high as 30%.1,4 – 6 Pneumonia is, therefore, a very important disease that needs to be recognized in the olderpopulation, whether they present from their home or from residential care. The rate of hospitalization for community-acquired pneumonia is higher in elderly patients. Kaplan et al7 conducted an important, large, and observational cohort study of all US Medicare recipients aged 65 and older who were hospitalized with pneumonia in 1997. They identified 623,718 hospital admissions for community-acquiredpneumonia. Compared with the overall incidence of hospitalization in the adult population of 4 per 1000, the incidence of hospitalization in those older than 65 years of age was 18.3 per 1000. More signifi-

P

neumonia is a common respiratory infection in the community that can affect people of all ages. The incidence increases markedly among the elderly, and, with an aging population, it willbecome an increasingly important disease. Therefore, it is important to know the specific characteristics of pneumonia and its differing effects on both the elderly and younger adult population.

From the Aged Care Department, and the Northern Clinical Research Centre, The Northern Hospital, Epping, Victoria, and The Department of Medicine, Austin and Northern Health, The University of Melbourne,Victoria, Australia. Reprint requests to Carol P. Chong, FRACP, Northern Clinical Research Centre, The Northern Hospital, 185 Cooper Street, Epping, Victoria, Australia. Email: carol.chong@nh.org.au Drs. Carol P. Chong and Philip R. Street have no financial disclosures to declare and no conflicts of interest. Accepted February 26, 2008. Copyright © 2008 by The Southern Medical Association...