Venous Congestion

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Generalised (Systemic) Venous Congestion

  • Usually associated with increased in circulation time due to cardiac pumping inefficiency.
    • The cardiac inefficiency is usually the result of:
      1. Cardiac disease, e.g.
        • Valvular disease
        • Myocardial degeneration
        • Cardiac malformation
      2. Increased pulmonary vascular resistance
        • Due to fibrosis or emphysema.
    • Reduced cardiac output gives an increased circulation time and a larger venous volume.
    • The relative quantity of deoxygenated blood in tissues rises.
  • Some organs are more susceptible to venous congestion than others.


  • Severe congestion results in increased size and weight of organs.
  • Encapsulated organs (e.g. spleen, liver):
    • Become swollen.
      • Turgid on palpation.
      • Have rounded free borders.
    • Are frequently darker red or purple.
    • Ooze dark (deoxygenated) blood on cut surface.
  • Oedema fluid may be seen (e.g. lung) if the condition is prolonged.
    • E.g. in the lung.
  • Accumulation of deoxygenated blood often results in cyanosis of tissues.
  • Where the condition persists, hypoxia induces degenerative changes and fibrosis.
    • Replacement of degenerate tissue by more compact fibrous tissue often leads to irregular surface depressions known as induration.
  • Where changes are more insidious, cellular and organoid atrophy may occur with diminution in size.


  • Severe congestion can induce:
    • Oedema formation
      • E.g. in the lung, associated with cardiac mitral valvular disease.
    • Stagnation hypoxia and capillary damage
    • Minor capillary haemorrhage is induced by hypoxia.
    • Fatty change
      • Degenerative change, characterised by fatty change, occurs when whole parenchymatous organs are affected.
        • E.g. the liver and kidneys.

Localised Venous Congestion

  • Affects individual organs or tissues.
  • May be
    • Acute
      • E.g. due to sudden blockage of drainage.
    • More chronic.
      • A slower but progressive blockage to venous drainage.
      • May result in tissue atrophy.


  1. Extra-vascular pressure, for example
  2. Intra-vascular obstruction
  3. Vasculitis
    • Inflammation in and around the vessel wall (phlebitis).
    • May be iatrogenic.


  • The affected organs or tissues show similar changes to venous congestion of systemic origin.
    • Here, the changes are confined to one organ or tissue area.
  • Organ displacements, e.g. intussusception, often show venous congestion followed by hypoxic degeneration and sloughing of tissue.


  • Affected tissues are seen to be congested .
    • Red blood cell stasis in venules and capillaries.
  • Degeneration of tissue cells in the area affected.
    • Varying numbers of inflammatory cells around these degenerate foci.
      • Oedema and leaked plasma protein deposits.


  • Sequelae depend on:
    • Severity
    • Speed of onset of hypoxia
    • Presence of alternative routes of venous drainage.
  • The usual effect is hypoxic localised degeneration.
  • Insidious, long-standing congestion tends to result in a combination of fibrosis and atrophy.

Hypostatic Congestion

  • Seen in long-term recumbent, chronically ill animals, or those dying slowly.
  • The term refers to congestion of the dependant parts of an organ in a failing circulation.
    • In cases of paired organs, it applies to the dependant organ .
  • Particularly affects the lungs and kidneys.