Ascites
Basic Information 
Clinical Presentation
Physical Exam Findings
• Ventral abdominal or distal limb edema is often present.
• Other clinical signs are variable and depend on the cause of ascites.
• Rectal examination may be abnormal, with organ enlargement, intestinal distension, or palpable masses if intraabdominal neoplasia is the cause.
Etiology and Pathophysiology
• Abdominal neoplasia may result in obstruction of abdominal lymphatics or production of excess peritoneal fluid (especially with mesothelioma) and may result in ascites.
• Right-sided heart failure causes congestion of the venous circulation and increases capillary hydrostatic pressure, resulting in a transudative abdominal effusion.
• Hypoproteinemia may result from protein-losing enteropathy or protein-losing nephropathy, causing a decrease in colloid oncotic pressure that results in loss of fluid from the vascular space.
• However, clinically apparent ascites is uncommonly seen with right heart failure or hypoproteinemia in horses because of the large capacity of the equine peritoneal cavity.
• Also, in contrast to other species, ascites rarely accompanies hepatic disease in horses.
