Ascites in Dogs – Causes, Symptoms, Diagnosis and Treatment

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Ascites, also known as abdominal effusion, is a common symptom seen in many diseases in veterinary medicine. When noticing any signs of ascites in your dog, it is essential that you bring your pet to the veterinarian immediately for diagnosis and treatment.

In this article, we discuss everything you need to know about ascites in dogs: what it is, possible causes, diagnosis and treatment. 

Symptoms of ascites in dogs - I Love Veterinary

What is Ascites in Dogs?

Ascites in dogs is the medical term to define abnormal fluid buildup within a canine’s abdomen. This fluid may be:

  • Blood
  • Bile: greenish-yellow fluid that aids with digestion of fats
  • Urine
  • Exudate: fluid that is rich in protein and comes out of blood vessels when inflammation is present
  • Transudate: watery low protein fluid that results from pressure 
  • Chyle: milky fluid made of lymphatic fluid and fat. 

It is not a disease itself, but rather a result of an underlying condition, meaning that the cause must be identified to treat ascites. 

French bulldog - I Love Veterinary

What Causes Ascites In Dogs?

There are many causes of ascites in dogs, and some of them are related to organ dysfunction and failure. Let’s look at some of the underlying causes of heart failure:

  • Right-sided heart failure occurs when the right ventricle (part of the heart that receives blood and pumps it to the lung) cannot perform its function. The blood backs up into the vessels and causes pressure, which leads to leakage and buildup of fluid in the abdomen. 
  • Trauma involving traffic accidents and injuries can cause ascites due to internal bleeding.
  • Liver failure results in high blood pressure and causes fluids to go out of the blood vessels and accumulate in the abdomen. 
  • Peritonitis causes ascites as the result of the inflammation of the abdominal cavity (peritoneum) commonly induced by a bacterial infection. 

Other causes of ascites are abdominal tumors, kidney failure, nephrotic syndrome, heartworm, bladder rupture, protein-losing enteropathy.

Symptoms Of Ascites In Dogs

The most noticeable sign of ascites is a distended abdomen, which can be accompanied by abdominal pain. Even though ascites is a secondary sign of many conditions, it can cause other symptoms and discomfort in your dog, such as vomiting, difficulty breathing, lack of appetite, panting, and anemia. This is due to the buildup of fluids and pressure in the surrounding organs, including the kidney, heart, lungs, liver.  

Diagnosing symptoms of ascites with x-rays - I Love Veterinary

How is Ascites in Dogs diagnosed?

The goal of the diagnostic procedures is to get to the underlying cause of the fluid buildup in your dog’s body. History of the patient and physical examination (palpation of the abdomen) are the first steps to determine the cause.

Your veterinarian will ask questions like: how long has the enlargement of the abdomen been present? What other changes in behavior and appearance have you noticed in your dog?

Then your veterinarian will proceed to the diagnostic tests which may include:

  • X-rays or CT scan
  • Urinalysis 
  • Complete blood count
  • Abdominocentesis: this is a minimally invasive procedure that involves taking fluid from the abdomen with a needle for examination

The consistency and color of the fluid can tell your veterinarian a lot about the possible causes. For instance, when your vet is performing abdominocentesis, and they see a watery-like (transudate), pale yellowed-colored fluid, they may suspect congestive heart failure or even a tumor. 

Further tests may be necessary to diagnose certain conditions. For example, electrocardiograms (ECG) and ultrasounds will be used to accurately diagnose congestive heart failure. 

Injured dog - I Love Veterinary

What is the Treatment for Ascites In Dogs? 

Abdominocentesis can also alleviate the discomfort from ascites. However, treatment is entirely based on the underlying condition. If the cause is left untreated, ascites will probably come back. 

Some of the causes of ascites may be treated with medication. Others may require surgery. 

A special diet, low in salt, may be prescribed to control the fluid accumulation in your dog’s abdomen related to conditions like congestive heart failure and liver malfunction. 


A distended abdomen on your dog is something that should never be overlooked as it may be a sign of a serious disease. It is essential that you follow your vet’s advice for the prompt recovery of your canine companion. 

If you would like to say a special thank you to the veterinary team for all their effort and exceptional care they provide to your furry family member, check out this article with some fantastic gift ideas! 

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Arais is a writer and virtual assistant for pet business owners and veterinarians. She is a graduated animal care assistant and has done work experience in veterinary clinics. She is going to start a degree in Veterinary Nursing In Ireland this year! When she is not writing, creating content or petting her three rescued cats, she's volunteering in an animal sanctuary and fostering kittens!