Pathological lung tissue changes in common infectious diseases.

Infectious diseases of the lung remain a major cause of morbidity and mortality worldwide and their diagnosis often relies on characteristic histopathological patterns. Hence, this retrospective observational study analysed 90 archived lung biopsy, resection and autopsy specimens to compare pathological changes associated with bacterial, viral, fungal and tuberculous infections. Bacterial infections were the most common. They showed predominant acute inflammation and consolidation. Tuberculosis and fungal infections were characterized by granulomatous inflammation and caseous necrosis. Viral infections demonstrated alveolar damage. Distinct histopathological profiles correlated with specific infectious etiologies and clinical outcomes, underscoring the diagnostic and prognostic value of microscopic examination in infectious lung diseases.