Ascites in Dogs


Overview of Ascites in Dogs

Ascites is the abnormal accumulation of fluid in the abdominal cavity. The volume of the fluid can be quite subtle, or it may be significant, causing distention of the abdomen. In dogs, ascites has many causes, most of which can be very serious. Ascites is caused by the leakage of fluid into the abdomen from blood vessels, lymphatics, internal organs or abdominal masses.

Causes of Canine Ascites 

  • Hypoalbuminemia or a decrease in the blood albumin level
  • Severe liver disease
  • Right sided heart failure
  • Abdominal masses
  • Trauma
  • Peritonitis or inflammation of the inner lining of the abdomen
  • Bleeding disorders
  • Diseases of lymphatics
  • Obstruction of the hepatic vein or caudal (lower) vena cava causing compromises in blood circulation
  • What to Watch For

  • Abdominal distension
  • Breathing difficulty or increased respiratory effort
  • Abdominal discomfort
  • Lethargy
  • Cough
  • Vomiting
  • Diarrhea
  • Fever
  • Anorexia
  • Weakness
  • Diagnosis of Ascites in Dogs

    Certain diagnostic tests must be performed for a definitive diagnosis of the underlying cause of ascites. The following tests should be considered:

  • A complete history and physical exam should always be performed
  • Complete blood test (CBC)
  • Biochemical profile
  • Urinalysis
  • Chest and abdominal x-rays
  • Abdominocentesis or peritoneal lavage with fluid analysis and culture. This involves sampling of the fluid from the abdomen for analysis and cultured if infection is suspected

    Based on the results of these initial tests, further diagnostics might include:

  • Bile acid measurements
  • Serum lipase
  • Abdominal ultrasound and ultrasound guided biopsies
  • Echocardiogram
  • Endoscopy (a fiber optic scope that is placed through the mouth and into the stomach and small bowel. The mucosa can be visualized and biopsies obtained)
  • Treatment of Ascites in Dogs

    An accurate diagnosis is needed for proper therapy. Pending a definitive diagnosis, certain treatments may be appropriate:

  • Therapeutic abdominocentesis (removing a larger amount of fluid from the abdomen) if the amount of abdominal distention is compromising the animal’s ability to breath
  • Diuretics to promote fluid excretion
  • Oxygen therapy if the animal is in respiratory distress
  • Intravenous fluids in cases of shock or dehydration
  • Transfusions of blood products
  • Antibiotic therapy if infection is suspected
  • Home Care

    Keep your dog calm and minimize stress. Make sure your pet stays warm and provide fresh water if your pet wants to drink. Seek veterinary care immediately if your pet is having trouble breathing or is extremely weak.

    In-depth Information on Ascites in Dogs

    Ascites, itself, usually does not cause a problem, but the primary disease process causing the ascites can be a serious condition. Ascites is usually produced slowly and in small amounts; however, if a large amount of fluid is produced, or rapidly produced, an emergency situation may exist. Large amounts of free fluid in the abdomen may compress the diaphragm, leading to respiratory compromise and difficulty breathing. Fortunately, this is a rare occurrence.

    Another potential emergency situation is the rapid onset of ascites. If the ascites develops quickly, it is often associated with profound weakness or shock. The loss of intravascular (within the blood vessels) blood volume may lead to acute anemia and shock as fluid leaves the blood vessels and moves freely into the abdominal cavity. The most common cause of such an event is the rupture of a blood vessel within the abdominal cavity. Bleeding tumors within the abdomen or traumatic injury are likely causes.

    Most of the time, the fluid buildup is more gradual and an emergency situation is not present. Any amount of ascites is a significant finding, however, and steps should be taken to find a diagnosis. Ascites has many different causes and establishing a diagnosis is usually not difficult. A good physical exam, basic blood tests and evaluation of the ascitic fluid often lead to the diagnosis, or they provide a direction upon which further diagnostics need to be done.

    Hypoalbuminemia Causes

    Hypoalbuminemia is a decrease in serum albumin levels. Albumin is available through the diet, but it is also produced in the liver. The kidney functions to maintain albumin concentration in the plasma by preventing its excretion in the urine. Normal gastrointestinal function is needed for proper absorption. Albumin is responsible for much of the colloidal osmotic pressure of the blood, and thus is an important factor in regulating the exchange of water between the plasma and the interstitial compartment (space between the cells). Decreases in the albumin level (usually under 1.5 gm/dl) lead to a pressure gradient that causes fluid to leak out of the blood vessels, producing ascites.

  • Protein-losing nephropathy. Disease of the kidney’s glomerulus (filtration system) may produce a condition where protein is excreted through the urine resulting in very low plasma albumin levels. This may be caused by infectious, immune, neoplastic or idiopathic (unknown etiology) mechanisms.
  • Gastrointestinal diseases that prevents the absorption of albumin. If albumin is not being absorbed, low blood levels are to be expected. Some diseases causing this include gastrointestinal lymphoma, inflammatory bowel disease and intestinal lymphangiectasia.
  • Severe liver disease may cause ascites by decreased albumin production or by increased resistance to blood flow within the liver. Severe hepatitis and liver cirrhosis are examples.
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