From WikiVet English
(Redirected from Edema)
Jump to navigation Jump to search


Oedema is NOT a disease; it is the sign of a disease state.

  • Oedema is defined as :"The swelling of tissues resulting from accumulation of excess fluid in the intercellular tissue spaces and serous cavities."
  • Small amounts of fluid are normally present to lubricate cavities and viscera - this is not oedema.
  • Excess fluid may accumulate in:
    • Subcutaneous tissue and between muscle.
    • Serous cavities.
      • Depending on the cavity, this has different terms.
        • Thorax - hydrothorax.
        • Pericardium - hydropericardium
        • Abdomen - hydroperitoneum (ascites).
      • Anasarca is when there is generalised body cavity accumulation plus subcutaneous involvement.
    • Lungs.

Local oedema

General oedema

Composition of oedema fluid

  • Inflammatory oedema which produces an exudate.
    • This is a protein rich fluid containing many inflammatory cells.
  • Non inflammatory oedema which produces a transudate.
    • This fluid is low in protein and cells.
  • Transudates and exudates are distinguished by the following criteria:
Criteria Transudate Exudate
Appearance Clear/ pale yellow ("straw coloured") Dark yellow, red or brown. Often cloudy or opaque.
Consistency Thin, serous Viscous
Protein content 0.05 - 0.5%, mainly albumin Usually 2 - 4%
Coagulability No fibrinogen, no coagulation Contains fibrinogen, coagulates
Specific gravity Low (< 1.012) High (1.012 - 1.020) +
Cell content Very low. mesothelial cells, some macropahges and lymphocytes/Monocytes. High. Often macrophages, neutrophils, lymphocyes etc. Depends on cause and chronicity

  • Examples of transudates:
    • Ascites
      • Excessive fluid in abdominal cavity.
    • Hydrothorax
      • Excessive fluid in the thorax.
    • Hydropericardium
      • Excessive fluid in the pericardium.
    • Anasarca
      • Generalised tissue oedema most noticeable in subcutaneous tissues.
    • Ventral subcutaneous oedema
  • Seen in heart failure in horses and cattle.

Pulmonary Oedema