Pneumonia is an acute inflammatory disease of the lung parenchyma caused by infectious agents. It remains a leading cause of morbidity and mortality worldwide, particularly among children under five, the elderly, and immunocompromised individuals. This study provides a comprehensive analysis of the etiology, classification, pathogenesis, risk factors, clinical presentation, diagnostic methods, treatment principles, and preventive strategies of pneumonia. A theoretical and analytical review of modern scientific literature, clinical guidelines, and epidemiological data was conducted. The results indicate that pneumonia can be caused by a wide range of pathogens, including bacteria (e.g., Streptococcus pneumoniae), viruses (e.g., influenza, SARSCoV2), fungi, and atypical microorganisms. Classification is based on the setting of acquisition (communityacquired, hospitalacquired, ventilatorassociated, aspiration pneumonia) and anatomical distribution. Key preventive measures include vaccination (pneumococcal, influenza, COVID19), smoking cessation, hand hygiene, oral care, and management of underlying chronic diseases. Understanding the multifaceted aspects of pneumonia is essential for effective prevention, timely diagnosis, and appropriate treatment.

pneumonia, etiology, communityacquired pneumonia, hospitalacquired pneumonia, pathogenesis, prevention, vaccination, respiratory infection.

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