Rosh Emergency Medicine Practice Test

What is the most likely pathogenesis of aspiration pneumonia in a patient with a history of dementia?

1. Aspiration of colonized oropharyngeal fluid into the lower airways

2. Inflammatory reaction in the lower airways due to aspirated gastric fluid

3. Inhalation of infectious particles and deposition into the lungs

4. Pathogen colonization of nasopharynx that reaches lung alveoli via microaspiration

The correct answer is: Aspiration of colonized oropharyngeal fluid into the lower airways

Aspiration pneumonia commonly occurs when oropharyngeal secretions, which may be colonized with pathogens, are aspirated into the lower airways. In patients with dementia, there is often a compromised ability to manage oral intake, leading to increased likelihood of aspiration. This condition heightens the risks as individuals may have difficulty swallowing properly or maintaining a strong cough reflex, allowing oropharyngeal secretions, which harbor bacteria, to enter the lungs more easily. The pathogenesis of aspiration pneumonia primarily involves these colonized secretions. When aspirated, the bacteria present in these fluids can lead to infection, marked by pulmonary inflammation and consolidation in the affected areas of the lung. This correctly identifies the mechanism by which aspiration pneumonia develops in such vulnerable patients, confirming that aspiration of colonized oropharyngeal fluid is the primary cause. Other options, while related to aspiration and infection processes, do not address the specific mechanism most relevant to patients with dementia. For instance, the inflammatory reaction due to aspirated gastric fluid could occur, but it generally lacks the direct connection to bacterial colonization typically seen in aspiration pneumonia. Inhalation of infectious particles is a separate process that is more related to classic pneumonia rather than aspiration specifically. Likewise, micro