Ascites is defined as the buildup of free fluid in the abdomen. It is characterized by a distended belly, which may be accompanied by nonspecific clinical signs such as lethargy. Ascites can be a symptom of other conditions, most commonly liver disease or right side heart failure, and cannot be treated successfully without also addressing the underlying cause. The prognosis depends on the source of the ascites.

Free fluid can build up in the abdomen when blood flow is impeded, whether due to liver disease, heart failure, or other conditions. This buildup is referred to as ascites (or abdominal effusion) and is characterized by a distended abdomen. Treatment and prognosis will vary depending on the underlying cause, since removing the accumulated fluid will not fully resolve the condition and may, in fact, encourage further ascites formation.

When fluid builds up in the abdomen, your dog's stomach will be visibly distended. Other clinical signs rising from the underlying cause for ascites (or the ascites itself) include:

Ascites is a symptom of many other conditions. One of the most common is liver disease, which leads to an increase in pressure in the vessels that lead to the liver. When blood flow is impeded, free fluid can build up in the abdomen. Fluid can also accumulate when the liver produces less albumin, a serum protein that helps keep water in the blood at the capillary level.

Another common cause of ascites is heart disease, specifically right side heart failure. With congestive heart failure, the heart is unable to pump blood out effectively, leading to a fluid build-up in other areas of the body. Other causes for ascites include hepatitis, kidney failure, and hypoproteinemia.

The veterinarian may make a circumstantial diagnosis of ascites based on your dog's distended abdomen and other physical findings. Laboratory testing, including blood work and a urinalysis, may be conducted both to discover the cause of the ascites and to determine your dog's overall condition. Radiographs and abdominal ultrasounds can confirm the presence of fluid in the abdomen, and a sample of the fluid can be withdrawn with a needle for cytologic examination and culture.

Further diagnostic tests may be required to reveal the extent of the underlying condition. If the veterinarian suspects that the ascites is a symptom of liver disease, a chemistry panel, and complete blood count may be performed. Other tests, such as serum bile acids and ammonia tests, are also very useful for measuring the liver function. In cases of heart failure, thoracic radiographs, and a Knott's test for heartworm may be useful for diagnosis.

A full diagnosis of the underlying condition is vital to proper treatment.

Treatment for ascites varies according to the underlying condition. The fluid can be removed via abdominocentesis, but this is only a temporary solution, as fluid can build up again if the cause of the ascites is not addressed. Unless your dog is having difficulty breathing because of the amount of fluid in the abdomen, the veterinarian most likely will not recommend this procedure. Your dog will lose albumin along with the fluid and decreasing pressure in the abdomen may lead to an increase in the fluid buildup.

Instead, a diuretic to increase the loss of water through urine, combined with a low sodium diet, is more often used to manage ascites. During this time, the condition causing ascites will also need to be treated, with treatment ranging from special diets for dogs with liver disease to drug therapy to improve cardiac function.

During the recovery process, provide your dog with a quiet and secure place to rest. Keep your dog calm and restrict activity in order to minimize stress. If your dog received treatment for the condition that is causing ascites, monitor him or her daily, and check that the ascites is resolving. Your veterinarian will provide you with instructions for care and let you know what to expect over the next few days. Follow-up exams may be recommended to ensure that your dog is healing well.

The prognosis for recovery is highly variable and depends on whether or not the underlying condition can be successfully treated.

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There are a few different treatments that the veterinarian may suggest. One of which may be abdominocentesis. This treatment is only a temporary fix and is usually only recommended if your dog is having trouble breathing. It can cost between $420 and $720. The other option that the veterinarian may suggest is the use of a diuretic. A diuretic can help increase the amount of water lost through urination. Combining a diuretic (e.g. Furosemide) with a low sodium diet can help reduce the fluid buildup in the abdomen. Furosemide 40mg/80mg can cost $13/$18 per 100ct. There is prescription dry dog kibble that promotes cardiac health that would be low in sodium. An 18 pound bag of this special kibble can cost $55-$78. The veterinarian may be concerned about your dog’s cardiac function and may prescribe cardiac improving drugs such as Spironolactone. Spironolactone 25mg can cost between $16 and $26 per 100ct. bottle. In total, the cost of all of these treatments can range from $504 to $549. Fluid buildup in the abdomen is nothing to take lightly and should always be treated by the veterinarian.