肺炎 I: 定義、リスク要因、分類

Pneumonia is a lung parenchymal infection affecting one or both lungs. The alveoli, tiny air sacs essential for oxygen exchange, become engorged with pus and fluid. This severely hinders breathing, decreases oxygen absorption, and causes significant pain during respiration, making it an acute respiratory infection that requires prompt attention.

Risk factors include air pollution, smoking, corticosteroid and immunosuppressive therapy, stroke, prolonged immobility, inhalation of toxic substances, tracheal intubation, and abdominal or thoracic surgery. Age also plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to less robust immune systems.

Community-acquired pneumonia occurs in community settings or within the first 48 hours after hospitalization, commonly caused by Streptococcus pneumoniae and Haemophilus influenzae. Medical care-associated pneumonia develops 48 hours or longer after hospital admission, includes ventilator-associated pneumonia, and occurs in patients with recent hospitalization or long-term care facility residence.

Hospital-associated pneumonia develops 48 hours or longer after admission without being present at hospitalization. Ventilator-associated pneumonia occurs 48 hours after endotracheal intubation. Healthcare-associated pneumonia affects patients hospitalized in acute care facilities for at least two days within 90 days of infection, particularly those in intensive care units.

Aspiration pneumonia arises from inhaling food, liquid, vomit, or saliva into the lungs. It typically occurs in individuals with difficulties swallowing or impaired gag reflexes. This type of pneumonia is particularly common in patients with neurological conditions or those unable to protect their airway during swallowing.

Opportunistic pneumonia occurs in individuals with compromised immune systems, such as AIDS patients, chemotherapy recipients, or organ transplant patients. Opportunistic pathogens like Cytomegalovirus and Aspergillus typically do not cause disease in healthy individuals but lead to serious infections when immune defenses are compromised.

Hospitalization, particularly in intensive care units or when mechanical ventilation is required, markedly heightens pneumonia risk. Tracheal intubation and prolonged immobility compromise natural lung defenses. Understanding these risks is vital for pneumonia prevention and timely diagnosis through pneumonia nursing management and prevention strategies.