MODERN VIEW FROM UKRAINE ON ETIOLOGY, PATHOGENESIS AND CLINICAL-DIAGNOSTIC ASPECTS OF COMMUNITY-ACQUIRED PNEUMONIA IN CHILDREN
Authors: Smiyan Oleksandr , Taramak Liudmyla , Smiian Kateryna , Vasilyeva Olena , Loboda Andriy , Petrashenko Viktoriia , Moshchych Olexandr , Vysotskyi Ihor , Horbas Victoria , Manko Yuliia , Holiuk Kateryna , Aleksakhina Tetiana 
Published: December 2023

Pneumonia is a disease characterized by lung tissue inflammation and the development of respiratory failure. Pneumonia is the most common infectious cause of childhood mortality, occurring every 43 seconds worldwide. Despite advancements in medicine and the use of cutting-edge diagnostic, treatment, and preventive technologies, the incidence of pneumonia remains relatively high, especially in resource-poor countries, adversely affecting the socio-economic life of society. Objective: To summarize contemporary scientific perspectives on the classification, etiology, pathogenesis, and clinical-diagnostic aspects of community-acquired pneumonia in children. Materials and Methods: The literature search was conducted using PubMed, Scopus, Web of Science, WHO, UNICEF databases, international protocols, as well as domestic scientific manuals and professional publications, and medical care standards. Search terms included "community-acquired pneumonia," "pneumonia in childhood," and "pneumonia in children." The analysis utilized methods such as a systemic approach, epidemiological analysis, bibliosemantic analysis, and graphical representation. Results: It was conducted the search and analysis of modern scientific medical literature on community-acquired pneumonia in childhood. Pneumonia is a leading infectious cause of illness and hospitalization in children worldwide. Bacteria, viruses, and mixed infections are identified among the main etiological agents, with cases of non-specific pathogens also observed. The variation in pathogens is presented based on age groups. It is discussed major risk factors for community-acquired pneumonia and pathways of pathogen penetration. Modern insights into the disease's pathogenesis are analyzed, involving a complex process with stages characterized by the development of infectious toxemia, respiratory failure, and disturbances in water-electrolyte balance. The main clinical symptoms are described according to the child's age, along with contemporary methods of laboratory and instrumental diagnostics of community-acquired pneumonia. Conclusions: Information from scientific literature is provided on the contemporary definition, classification, epidemiology, etiology, pathogenesis, clinical presentation, and diagnostics of community-acquired pneumonia in childhood. Currently, severe and non-severe forms of pneumonia are distinguished based on respiratory rate and additional threatening symptoms. The increasing incidence of viral-bacterial pneumonia is noted, with bacteria remaining the primary etiological factor. Pneumococcus and Haemophilus influenzae type B predominate among bacteria. It is also observed an increase in cases of viral pneumonia, attributed to respiratory syncytial and coronavirus infections. The disease's pathogenesis involves multiple phases with the involvement of other organ systems. Clinical features of community-acquired pneumonia include fever, respiratory failure, and cough. Laboratory diagnostic methods include a complete blood count, determination of C-reactive protein levels, and procalcitonin. Among diagnostic methods, chest X-ray, computed tomography, and ultrasound diagnostics of the chest organs are considered the most conclusive.