Aspiration and infection in the elderly : epidemiology, diagnosis and management.

Aspiration of the oropharyngeal or gastric contents by elderly persons often leads to lower respiratory tract infections, such as aspiration pneumonia or pneumonitis. The existence of dysphagia and aspiration in elderly patients are important factors in the occurrence of aspiration pneumonia, but are not sufficient to cause aspiration pneumonia in the absence of other risk factors. Salivary flow and swallowing can eliminate Gram-negative bacilli from the oropharynx in healthy persons. However, elderly persons may have diminished production of saliva as a result of medications and oral/dental disease, leading to poor oral hygiene and oropharyngeal colonisation with pathogenic organisms. When dysphagic patients aspirate pathogenic bacteria while swallowing food or liquids, they must also have decreased defences, such as impaired immunity or pulmonary clearance, in order to develop aspiration pneumonia.