TY - CHAP M1 - Book, Section TI - Aspiration, Empyema, Lung Abscesses, and Anaerobic Infections A1 - Enfield, Kyle B. A1 - Sifri, Costi D. A2 - Grippi, Michael A. A2 - Antin-Ozerkis, Danielle E. A2 - Dela Cruz, Charles S. A2 - Kotloff, Robert M. A2 - Kotton, Camille Nelson A2 - Pack, Allan I. PY - 2023 T2 - Fishman’s Pulmonary Diseases and Disorders, 6e AB - Aspiration pneumonia, lung abscess, and necrotic lung are parenchymal lung diseases. Aspiration pneumonia refers to the pulmonary consequences that follow abnormal entry of fluid, particulate substances, or endogenous secretions from the upper airways or gastric contents into the lower airways (Chapter 69). Aspiration pneumonia develops following the disruption of a series of formidable host defense mechanisms that normally protect the lower airways. These defenses include, among others: glottic closure via the cricopharyngeus muscle, the cough reflex, and ciliary clearance of the airway. The material aspirated must generate an inflammatory response or cause obstruction. The nature of the pneumonia that develops depends on the inoculum and the host response. Historically, anaerobic bacteria were considered the most common pathogens in this setting, reflecting both pathogenic potential and importance in the normal flora of the upper airways; however, recent data have challenged this view. Risk factors for aspiration may be transient (anesthesia, intoxication) or persistent (e.g., neuromuscular disorders, achalasia). Recurrent aspiration risk depends on recognition and resolution of the inciting defect.1,2 SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1195014941 ER -