Aspiration-Related Alveolar Disease: From Acute Injury to Chronic Pulmonary Sequelae

Aspiration-related lung diseases comprise a broad spectrum of disorders resulting from the entry of oropharyngeal or gastric contents into the lower respiratory tract. Clinical manifestations range from acute aspiration pneumonitis and aspiration pneumonia to chronic airway and parenchymal injury, including bronchiolitis, bronchiectasis, fibrosis, and lipoid pneumonia. Aspiration pneumonitis is driven primarily by chemical injury, whereas aspiration pneumonia results from infection caused by aspirated microorganisms in susceptible hosts. Contemporary microbiologic data indicate that aspiration pneumonia more closely resembles community- or hospital-acquired pneumonia than the classic anaerobic infection paradigm. Imaging plays a central role in diagnosis, yet radiographic findings are highly variable and frequently contribute to diagnostic uncertainty. Chest radiography may be entirely normal or demonstrate only subtle gravity-dependent or perihilar opacities, while in other cases it reveals multifocal or diffuse air-space opacities that overlap substantially with other infectious and inflammatory lung diseases. Computed tomography is considerably more sensitive and depicts a broad spectrum of acute and chronic aspiration-related abnormalities, including ground-glass opacities, consolidation, tree-in-bud opacities, centrilobular nodules, aspiration bronchiolitis, bronchiectasis, fibrotic remodeling, and dendriform pulmonary ossification, while also demonstrating characteristic findings in select aspiration-related conditions. Recognition of these imaging patterns, together with clinical history and swallowing evaluation, is critical for establishing the diagnosis and identifying the underlying mechanism of aspiration. Management requires integration of clinical history, imaging, swallowing assessment, and selective adjunctive testing, with treatment directed toward supportive care, appropriate antimicrobial therapy when infection is present, prevention of recurrent aspiration through correction of the underlying cause, and multidisciplinary management when indicated. Early diagnosis and intervention are essential to prevent recurrent lung injury and progressive pulmonary damage.