Giới thiệu
Pneumonia - Community-Acquired Pediatric_Disease Background 1Community-acquired pneumonia (CAP) in children is a previously healthy child presenting with signs and symptoms of lower respiratory tract infection (LRTI) acquired outside of the hospital or health care facility.
Dịch tễ học
There are approximately 120 million cases of pneumonia reported worldwide each year. The prevalence of childhood pneumonia differs considerably across regions worldwide due to variations in the prevalence of risk factors and causative pathogens. Community-acquired pneumonia accounts for approximately 2 million outpatient visits annually in the United States, and 2.5 million cases each year in Europe. The Southeast Asia region accounts for 39% of the estimated new childhood pneumonia cases each year. Children <2 years of age have the highest incidence of pneumonia, with male children being more commonly affected than females across all age groups.
Nguyên nhân
Pneumonia - Community-Acquired Pediatric_Disease Background 2The most common bacterial cause of childhood pneumonia is Streptococcus pneumoniae. S pneumoniae usually causes about 1/3 of radiographically confirmed pneumonia in children <2 years of age. Pneumonia secondary to group A Streptococcus and Staphylococcus aureus is more frequently associated with empyema or pediatric intensive care unit (ICU) admission.
Viruses commonly affect children <1 year of age more than those aged >2 years, with respiratory syncytial viruses (RSV) being the most frequently detected virus. Adenoviruses, bocavirus, human metapneumovirus, influenza A and B viruses, parainfluenza viruses, coronaviruses, and rhinovirus are less frequently identified. Mixed infection may occur in 8-40% of CAP cases.
Sinh lý bệnh
Pneumonia occurs when pathogens invade the lower respiratory tract through inhalation, aspiration, direct invasion of the respiratory epithelium, or hematogenous spread. Infection develops after the body's normal defense mechanisms are overcome, leading to inflammation of the alveoli and surrounding lung tissue. The resulting inflammatory exudate impairs gas exchange and oxygenation.
Yếu tố nguy cơ
Risk factors for childhood pneumonia include chronic respiratory disorders (eg cystic fibrosis and bronchiectasis), immune deficiency, congenital heart disease, malnutrition, and low birth weight.