gray hepatization
Summary
Third stage of lobar pneumonia (days 4-6) in which the consolidated lung becomes gray-brown, dry, and firm as red cells lyse and neutrophils/fibrinopurulent exudate predominate. Lung still has a liver-like consistency, hence 'hepatization.'
Detail
Lobar pneumonia, classically due to Streptococcus pneumoniae, progresses through four stages: congestion (day 1-2), red hepatization (day 3-4), gray hepatization (day 4-6), and resolution (day 7+). In gray hepatization, RBCs are degraded and the alveoli are filled with a fibrinosuppurative exudate of neutrophils and fibrin, giving the lobe a pale gray, dry, firm appearance. The pleura often shows a fibrinous exudate (pleuritis), and patients still present with fever, productive cough, and bronchial breath sounds. Resolution follows as macrophages clear debris and the architecture is restored without significant scarring. High-yield boards association: S. pneumoniae lobar pneumonia.
Sources
- Robbins Basic Pathology 10th ed
- First Aid for USMLE Step 1 2024
- Pathoma
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