Viral and Inflammatory Lung Injury: Pathophysiology, Diagnostic Strategies, and Clinical Management

Abstract

Acute respiratory disease may arise from viral infection, bacterial colonization, inhaled toxicants, or complex interactions between pathogens and host immunity. Although these conditions have different initiating causes, they can converge on airway epithelial injury, inflammatory-cell recruitment, altered surfactant function, impaired gas exchange, and, in severe cases, acute respiratory distress syndrome (ARDS). This integrative narrative review synthesizes the supplied literature on SARS-CoV-2, respiratory syncytial virus (RSV), bacterial airway inflammation, lung metabolism, respiratory mechanics, inhalation injury, and biopsy findings in nonresolving ARDS. The reviewed studies indicate that respiratory pathology is heterogeneous: similar clinical syndromes may reflect different tissue-level processes, and extrapulmonary manifestations can accompany respiratory infection. Clinical assessment therefore benefits from combining symptoms and oxygenation with microbiological testing, imaging, respiratory-mechanics assessment when indicated, and selective histopathology in unresolved cases. Supportive care should be individualized to disease severity and underlying physiology, while invasive procedures and anti-inflammatory treatment require careful patient selection. Because this is a narrative synthesis of previously published studies rather than a new patient cohort, no pooled effect estimate or original clinical outcome is reported. The findings support a structured, mechanism-informed approach to diagnosis and management and highlight the need for prospective studies using standardized phenotyping.