If you’ve noticed your dog’s abdomen getting larger or suspect something isn’t quite right, it might be a good time to check it. One possible cause of this swelling is ascites in dogs, a condition that occurs when excess fluid accumulates in the abdominal cavity.

At first glance, ascites in dogs might just look like weight gain or bloating, but it’s actually a sign of something serious. This fluid buildup can make your dog uncomfortable and even cause difficulty breathing if it becomes severe. The condition can be linked to a range of medical problems, including liver disease, heart failure, kidney issues, cancer, or infections.

Here, we’ll talk about everything you need to know about ascites in dogs so you can give your pup the care it needs.

What Causes Ascites in Dogs?

Fluid buildup in a dog’s abdomen can result from different health issues, ranging from liver and heart disease to infections, cancer, and trauma. Here are the common causes of ascites in dogs:

Liver Disease

Health problems such as liver cirrhosis, hepatitis, and liver cancer can all lead to ascites. The liver is an organ responsible for maintaining fluid balance and producing proteins like albumin, which help keep fluids inside blood vessels. When the liver is damaged or isn’t functioning properly, it may fail to produce enough of these proteins, causing fluid to leak into the abdomen. 

Heart Disease

Heart disease, particularly right-sided congestive heart failure, is another major cause of ascites in dogs. The heart is responsible for pumping blood efficiently throughout the body. But when it starts to fail, blood can begin to back up in the veins, increasing pressure and forcing fluid to leak into the abdominal cavity.

Another heart-related condition that can lead to ascites is heartworm disease. In severe cases, heartworms can block blood flow, causing stress on the heart and leading to fluid retention. 

Kidney Disease

When a dog has kidney disease, the kidneys may start leaking essential proteins into the urine, leading to a condition called hypoalbuminemia. Since albumin is responsible for keeping fluid within blood vessels, a deficiency can cause fluid to seep into the abdominal cavity. Chronic kidney disease is one condition that can greatly contribute to ascites in dogs.

Cancer in the Abdomen

Canine cancer is another possible cause of ascites in dogs, particularly when tumors interfere with the normal drainage of fluid or trigger inflammation. Abdominal tumors, such as those affecting the liver, spleen, or lymph nodes, can block lymphatic flow and blood circulation, leading to fluid buildup.

Infections and Inflammation

Severe infections inside the abdomen can lead to a condition called peritonitis, which can cause fluid accumulation due to inflammation and leakage from infected tissues. Peritonitis can develop as a result of bacterial infections, fungal infections, or even pancreatitis. 

In some cases, the infection may be caused by a ruptured intestine or an abscess within an organ, leading to severe inflammation. In this case, dogs would require immediate medication attention.

Internal Bleeding from Trauma

Internal bleeding is another cause of ascites in dogs. This happens when your dog has suffered injuries from a car accident, fall, or another related case of trauma. When blood leaks into the abdominal cavity, it can create significant swelling, making the belly appear distended. 

What are the Signs of Ascites in Dogs?

While the most obvious sign is a swollen or distended abdomen, dogs with ascites often display additional symptoms depending on the underlying cause. 

Here are the key signs to watch for:

• Abdominal Swelling. The most noticeable symptom of ascites is a bloated or enlarged belly caused by fluid accumulation. The swelling may develop gradually or appear suddenly.
  
  

• Difficulty Breathing. As the abdomen fills with fluid, it can put pressure on the diaphragm, making it harder for your dog to breathe. You may notice labored breathing, rapid breathing, or constant panting even when they are at rest.
  
  

• Lethargy and Weakness. Dogs with ascites often become less active and may seem tired, weak, or unwilling to move. This can be due to discomfort from the swelling or an underlying disease such as heart failure or liver disease.
  
  

• Loss of Appetite and Weight Changes. While the abdomen may appear larger, some dogs with ascites lose muscle mass or experience overall weight loss due to illness. A loss of appetite is also common, especially in cases related to liver or kidney disease.
  
  

• Vomiting and Diarrhea. If ascites are caused by an issue affecting the digestive system, such as liver disease or an infection, dogs may vomit frequently or have diarrhea. This can lead to dehydration and worsening weakness.
  
  

• Excessive Thirst and Urination. Some conditions that cause ascites in dogs, such as kidney disease or some types of cancer, make them drink and urinate more than usual. If you notice your dog’s increased thirst and urination, it might be a possible indicator.
  
  

• Pale or Yellow Gums. If your dog’s ascites are related to liver disease or internal bleeding, your dog’s gums may appear pale or yellow. Checking your dog’s gums can provide a clue about their overall health.
  
  

• Restlessness or Discomfort. Dogs with ascites may have trouble getting comfortable when lying down. They might frequently shift positions and pace or seem anxious, especially if the fluid buildup causes pressure or pain.
  
  

• Collapse or Sudden Weakness. In severe cases, especially if internal bleeding is involved, dogs may collapse, become extremely weak, or struggle to stand. 

How to Diagnose Ascites in Dogs?

Diagnosing ascites in dogs will usually require a couple of tests. Just like any other condition, the diagnostic process will start with a vet checkup and then to the specific exams. 

Our vets will check for signs of abdominal swelling, labored breathing, weakness, and discomfort. We’ll review your dog’s medical history and ask questions about any recent symptoms you observed at home. 

We may also recommend imaging tests to detect any presence of liquids or identify potential causes. X-rays, ultrasounds, and CT scans will check your dog’s organs and detect any fluid buildup, if there is any.

Additionally, we will also perform abdominocentesis, a procedure where we insert a sterile needle into your dog’s abdomen to collect a sample of the fluid. The collected fluid is then analyzed in a lab. From here, we can get a good view of what’s going on.

Blood tests and urinalysis are essential to assess your dog’s overall health and check for conditions contributing to ascites. These tests can reveal signs of infection, anemia, organ dysfunction, or abnormal protein levels.

If heart disease is suspected, we may make use of ECGs to assess your dog’s heart function. Specific tests may also be run to check for liver disease, kidney failure, heart disease, or cancer markers.

What is the Treatment for Ascites in Dogs?

The treatment for ascites in dogs depends on the underlying cause of the fluid buildup. Treatment can involve medications, dietary changes, fluid drainage procedures, or even surgery.

Here is how we treat ascites in dogs:

Treating the Main Cause

Since ascites can result from a variety of medical conditions, the primary focus of treatment is resolving or managing the root cause. If the issue is liver disease, medications and liver-support supplements may be prescribed to help improve liver function. In cases of heart failure, diuretics can be used to remove excess fluid, along with heart medications to strengthen heart function. 

If kidney disease is contributing to ascites, treatment may involve fluid therapy, diet modifications, and medications to help manage protein loss. Dietary changes will require a specialized diet that will involve low-sodium dog food and other foods designed to aid with recovery.

For dogs with infections or peritonitis, antibiotics, and anti-inflammatory drugs will be used to fight the infection. 

If cancer is the cause, treatment might include surgery, chemotherapy, or palliative care to slow tumor growth and relieve discomfort. Tumor removal, repairing a damaged organ, or addressing structural abnormalities may help resolve fluid buildup in some cases.

In severe cases where fluid buildup causes extreme discomfort or breathing difficulties, we might drain the excess fluid. While this can provide immediate relief, it is not a long-term solution, as fluid can quickly return if the underlying disease is not controlled.

How to Prevent Ascites in Dogs?

While ascites in dogs aren’t always preventable, you can help reduce the chance of fluid buildup in your pup’s abdomen. Since ascites are often linked to heart disease, liver problems, kidney issues, or cancer, we can focus on these.

1. Regular Checkups. Routine exams help detect heart, liver, or kidney disease early before they cause fluid buildup.

2. Heartworm Prevention. Keep your dog on year-round heartworm medication to prevent heart failure, a major cause of ascites.

3. Healthy Diet. A low-sodium, well-balanced diet supports heart and liver health, reducing the chances of fluid retention.

4. Exercise and Weight Management. Keeping your dog active and having a balanced weight helps prevent obesity-related health issues.

Our dogs trust us with their lives. Keeping them safe means watching for the signs they can’t tell us about.

- Dr. Lidija Krvavac

Conclusion

Seeing your dog with a swollen belly can be scary, but understanding all about ascites in dogs and taking quick action can make all the difference. Since ascites are usually a sign of an underlying health issue, the best thing you can do is get your dog to the vet as soon as possible. 

Prevention is always better than treatment, so regular vet checkups, a healthy diet, exercise, and heartworm prevention can go a long way in keeping your pup healthy. If you ever notice signs like bloating, breathing trouble, or unusual weakness, trust your instincts and seek veterinary care early.