stages of community-acquired pneumonia
first stage--congestion, proteinaceous fluid, scattered neutrophils, and many bacteria in alveoli.
W/in a few days, stage of red hepatization: lung lobe has a liver-like consistency; alveolar spaces are packed w/ neutrophils, red cells, and fibrin.
In gray hepatization, lung is dry, gray, & firm, cuz red cells are lysed, while fibrinosuppurative exudate persists w/in alveoli.
Resolution: follows in uncomplicated cases. granular, semifluid debris ingested by macs, coughed up, or organized by fibroblasts growing into it. pleural rxn (fibrinous or fibrinopurulent pleuritis) may resolve or undergo organization, leaving fibrous thickening or permanent adhesions