Congestion and its organ manifestation

1. Definition

• Congestion = passive hyperemia: impaired venous outflow → blood accumulates in veins → ↑hydrostatic pressure → edema + hypoxia; affected organs appear bluish (cyanotic).
• Contrast active hyperemia (↑arterial inflow via vasodilation; red/pink) — inflammation, exercise, blushing, reperfusion.

2. Causes

Local (venous obstruction)

• Venous thrombus → embolism (DVT → pulmonary embolism; saddle embolus → sudden death).
• Venous compression / incompetent valves → ↑venous pressure.
• SVC syndrome: tumor compresses SVC → facial/neck/shoulder swelling + cyanosis.

Systemic

• Right-sided heart failure / CHF → generalized venous congestion.

3. Organ Manifestations

• Liver — nutmeg liver: centrilobular (zone 3) hepatocytes deoxygenated + fatty, periportal spared → nutmeg pattern; chronic → cardiac cirrhosis.
• Lung — brown induration: chronic pulmonary congestion (left HF/mitral stenosis) → microhemorrhage → heart failure cells (hemosiderin-laden macrophages) + septal fibrosis.
• Spleen: congestive splenomegaly ± fibrosis.
• Kidney: dilated stellate veins, livid pyramids.
• Fluid accumulation: hydrothorax, hydropericardium, ascites, anasarca, edema.

4. Consequences of Long-Standing Congestion

• Organ enlargement (hepato-/splenomegaly), brown induration (fibrosis + hemosiderin), skin atrophy, necrosis (bowel, testicle), edema, crural ulcers (post-thrombotic).

💡 High-yield: Congestion = passive (venous, bluish) vs active hyperemia (arterial, red). Two classic chronic pictures: nutmeg liver (right HF) and brown induration of lung with heart failure cells (left HF/mitral stenosis).