Category:Effusions

Effusions

• Increased amount of fluid in peritoneal, pleural or pericardial cavity
• Not a disease in itself
• Indicates pathological process affecting fluid production and/or removal

• Classification
  • Based on cell counts and total protein
    • Transudate
    • Modified transudate
    • Exudate
  • Haemorrhage
  • Chylous effusion

• Transudate and modified transudate are usually present in the clinical sign "ascites"

Transudate

Modified transudate

• High cells and low protein OR Low cells and high protein
• Yellow to serosanguinous, turbid
• Specific gravity 1.018 - 1.030
• Total protein 25 - 50g/L
• Nucleated cells 0.3 - 5.5 x10e9/L (up to 7 x 10e9/L)
• Mesothelial cells, macrophages, non-degenerate neutrophils, small lymphocytes

• Due to:
  • Cardiac disease
    • Increased hydrostatic pressure within blood vessels
    • May be compounded by hypertension
  • Chylous effusions (see below)
  • Lymphatic obstruction (neoplasia - e.g. papillary adenocarcinoma of the ovary in the bitch, also produces fluid)

Exudate

• High cells and high protein
• Turbid - red, yellow, white
• Specific gravity > 1.018
• Total protein > 30g/L
• Nucleated cells >3 x 10e9/L
• Neutrophils non-degenerate or degenerate, macrophages, lymphocytes, eosinophils (with parasites)

• Due to:
  • Inflammation of the pleural/abdominal cavities or their lining
    • Septic
      • Degenerate neutrophils
      • Intracellular bacteria
      • In horses
        • Yellow, brown turbid
        • Look for plant material - rupture or perforation of gut wall
        • Horses with gut rupture will quickly develop cardiovascular collapse
    • Non-septic
      • Non-derenerate neutrophils
      • No bacteria
      • In horses
        • Amber, slightly turbid fluid
        • Neutrophils > macrophages
      • e.g.FIP
  • Long standing modified transudate becomes exudate
  • Neoplasia (cell numbers really high)

Haemorrhage

• Turbid - red
• Specific gravity 1.025 - 1.040
• Total protein > 30g/L
• Nucleated cells 1.5 - 10 x 10e9/L
• WBC from peripheral blood (including neutrophils and macrophages)

• Recent or iatrogenic
  • Erythrocytes
  • Platelet clumps
• Long standing haemorrage
  • Macrophages with erythrophagia of haeme pigment
• In horses in addition to the above
  • Haemorrhagic diapedesis
    • Leakage of blood and fluid from the gut secondary to compromised vascular supply and venous return
    • Seen with interstitial necrosis/ischaemia
    • Fluid appears serosanguinous

Due to

• Most commonly seen in cats and dogs due to traumatic injury to the liver (e.g. infectious canine hepatitis), spleen (e.g. haemangiosarcoma) and kidney
• Warfarin toxicity
• Moldy sweet clover hay fed to pregnant cows may bleed from umbilical vessels into peritoneum
• Manual ablation of corpus luteum in cattle

Chylous effusion

• Opaque, milky
• Specific gravity > 1.017
• Total protein > 30g/L (variable)
• Nucleated cells 1.5 - 20 x 10e9/L
• Small lymphocytes, mature neutrophils, variable macrophages)

• Chyle
  • Triglycerides in fluid > in serum
  • Cholesterol in fluid < in serum
  • Formation of "cream top" (chylomicrons) if refrigerated
  • Does not deparate on centrifugation
  • Sudan III staining lipid droplets

Ectopic sources of fluid

• Urine
  • Uroabdomen
  • Transudate or modified transudate

• Bile
  • Bile peritonitis
  • Green in colour
  • Modified transudate or exudate

• Pancreatitis
  • Modified transudate or exudate