Aspiration pneumonia.

The growing population of older people worldwide represents a great challenge for health systems. The elderly are at increased risk of infectious diseases such as pneumonia, which is associated with increased morbidity and mortality related mainly to age-related physiological changes in the immune system (immunosenescence), the presence of multiple chronic comorbidities, and frailty. In pneumonia, microaspiration is recognized as the main pathogenic mechanism; while macroaspiration which refers to the aspiration of a large amount of oropharyngeal or upper gastrointestinal content passing through the vocal cords and trachea into the lungs is identified as "aspiration pneumonia". Although there are strategies for the prevention and management of patients with pneumonia that have been shown to be effective in older people with pneumonia, more research is needed on aspiration pneumonia, its risk factors and outcomes, especially since there are no specific criteria for its diagnosis and consequently, the studies on aspiration pneumonia include heterogeneous populations.