Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Nov 2024
Imaging of Aspiration: When to Suspect Based on Imaging of Bacterial Aspiration, Chemical Aspiration, and Foreign Body Aspiration.
Aspiration-related syndromes comprise a broad spectrum of diseases affecting the airways and lung parenchyma resulting from inadvertent entry of oropharyngeal or gastric contents into the respiratory tract. The diagnosis can be challenging given lack of self-reported symptoms and unwitnessed or silent aspiration events. Aspiration is a common finding in healthy individuals suggesting that host defenses play a critical role in the pathophysiology. ⋯ Acute syndromes include pneumonia, pneumonitis, and foreign body aspiration. In the more indolent form of aspiration, bronchiectasis, diffuse bronchiolitis, and interstitial lung disease can develop. A detailed understanding of associated radiographic findings for these syndromes can help to implicate aspiration as the cause for imaging abnormalities and ultimately optimize patient management.
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Semin Respir Crit Care Med · Nov 2024
Bacteriology of Aspiration Pneumonia: The Lung Microbiome and the Changing Microbial Etiology.
Aspiration pneumonia refers to the process of alveolar inflammation induced by the inhalation of oropharyngeal secretions into the lower respiratory tract. Predisposing factors comprise swallowing dysfunction, impaired cough reflex, and degenerative neurological diseases. Accumulating evidence projects a fading contribution of anaerobic bacteria in aspiration pneumonia at the expense of Gram-negative bacilli, with Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, becoming the predominant organisms recovered from respiratory specimens. ⋯ Understanding this complex temporal variability between microbiome-host associations was only made possible with the introduction of metagenomic sequencing. In this narrative review, we summarize existing knowledge and elaborate on the evolving microbiology of aspiration pneumonia including the link between oral microbiome and pulmonary aspiration. We also highlight the progress and challenges in instituting microbiome-targeted strategies for preventing and treating the sequelae of aspiration pneumonia.