Haemorrhagic Effusion

• 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