Definitions-and-clinical-manifestations

• Pneumonia: s/s (fever, cough, purulent sputum, dyspnea) + new infiltrate on chest imaging
• Community-acquired pneumonia (CAP): pneumonia acquired outside of hospital setting
• Hospital-acquired pneumonia (HAP): pneumonia acquired ≥48 hrs after hospitalization
• Ventilator-associated pneumonia (VAP): pneumonia acquired ≥48 hrs after intubation
• Lung empyema: accumulation of pus in pleural space
• Lung abscess: parenchymal necrosis with confined cavitation
• Aspiration pneumonitis: acute lung injury after inhalation of gastric contents without infection, though bacterial infection can occur within 24–72 hrs of injury