الفهرس 
Community acquired pneumoniaOnly 14 pages are availabe for public view
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Abstract
Pediatric Community-acquired pneumonia (CAP) is an acute infection of the pulmonary parenchyma in a child caused by a pathogen acquired outside the hospital, that is, in the community, or which appear within 48 hours of admission to hospital. whereas new pulmonary infiltrate on chest radiograph is needed for definite diagnosis. It is estimated that CAP is responsible for one-fifth of the deaths of young children, so it is an important cause of pediatric morbidity and mortality.
CAP usually presents with acute respiratory symptoms, but should always put in mind in patients with unexplained sepsis.
Causative organism may be bacterial, viral, fungal, parazitic or co infection. Defining causative organisms is a challenge. Clinical and radiological features don’t reliably distinguish between viral and bacterial aetiology, and obtaining cultures from the lower respiratory tract of young children is rare. The evaluation of upper respiratory tract secretions is only useful for viruses and atypical bacteria because typical bacteria are part of the normal flora colonising the upper respiratory tract. More specific but invasive investigations such as pleural aspiration are infrequently indicated and reserved for severe cases. Blood cultures are rarely performed in patients managed in the community.
Risk factors include healthy children below 5 years of age, boys document more incidence in all ages. Also, preterm, tobacco exposure, pollution exposure, immunodeficient, neurological disease, chronic respiratory disease and low socioechonomic standards are important risk factors.
Microorganisms may gain access to the lower respiratory tract through four different pathways: Inhalation of contaminated droplets, hematogenous spread, direct extension from adjacent infected foci and aspiration of gastrointestinal or oropharyngeal contents. The causative agents vary according to the age of the child and, to a lesser extent, the setting in which the infection is acquired. Generally, viruses are the most common cause of community-acquired pneumonia in children younger than 5 years; the incidence of which decreases with increasing age. Viruses alone account for up to 50% of cases in young children. Respiratory syncytial virus is the commonest among viruses accounting for 30% of viral pneumonia. Other viruses include influenza, parainfluenza, and human metapneumovirus, and recently the newly discoveredSARS-COV-2 in COVID 19 pandemic. Streptococcus pneumoniae is the commonest bacterial cause across all ages, accounting for 30-40% of cases. Coinfection by viral with bacteria has been reported in up to 33% of cases. Severity assessment will improve the outcome of patient management as it assists the clinician in deciding the appropriate place of management (PICU for severe cases and wards for simple ones), and helps guide empirical antimicrobial. Regarding severity assessment, different scores are used AS WHO classification, PRESS, RISC, PRIOM, also PSOFA, PIM, PRISM scores, as regarding mortality assessment, gives note about severity.
MxA is a protein that belong to a group of IFN-induced GTPases involved in the control of intracellular pathogens. Its level is induced <1.2 h after infection and has a half-life of 2.3 days. It achieves peak concentration at 16 h and remains increased in the presence of increased IFN. SO, MxA may be used as biomarker for assessment of severity of CAP.
The aim of this study is to assess the value of MxA in prediction of CAP severity in hospitalized pediatric patients.