Dog Swollen Abdomen: Causes and Symptoms

While you may notice your dog looking a little pudgy after indulging in a big meal, this should be a mild and temporary change. Bloating that is more obvious and persistent could indicate there is something amiss.

This article explores the more common causes of canine abdominal swelling and discusses the additional symptoms that may arise. It will also examine the range of diagnostic tests and therapy options your vet may consider when assisting your pet.

What is a Swollen Abdomen?

It can be tricky for some dogs to determine if their abdomen is truly swollen. This is especially the case for obese pooches and females who have had multiple litters. However, if there is true abdominal swelling, this will usually be clearly visible to you as an owner.

You may notice the abdomen bulging more than it usually does, protruding from the sides, or looking rounded. This will be the case at all times of the day, and it may be more obvious when your dog is lying on its side.

It may be useful to compare your dog to photographs from their past. A normal abdomen should be tucked in rather than bulging out.

When is It a Cause for Concern?

We tend to worry about a swollen abdomen when it persists. If your dog gets a bit bloated after overeating or eating too quickly, the gas will soon pass, and any swelling will be gone within the day.

We also worry about abdominal swelling when it occurs alongside other symptoms. This could include excessive thirst, lethargy, pale gums, or vomiting.

Some dogs may also present with weight loss. While their belly will look fatter, you may notice their spine and hip bones are suddenly more prominent, or their ribs are more visible.

Common Causes of Swollen Abdomen in Dogs

Many different things can cause a dog’s abdomen to swell, some of which are more serious than others. Let's examine some of the conditions we see most in clinical practice.

Bloat or Gastric Dilatation-Volvulus (GDV)

Bloat is a well-known cause of abdominal swelling. The dog develops a tense and distended stomach, which swells within hours and rotates on its axis. A dog with bloat is acutely unwell, with signs such as panting, drooling, retching, and restlessness.

Though dogs can potentially develop bloat, the risk is higher in deep-chested breeds such as Great Danes and Irish Wolfhounds. This is a true emergency that requires immediate intervention if the patient is to survive. Call an emergency vet right away if you suspect your dog may have developed a GDV.

Time is of the essence. Your vet will release the excess gas from your dog’s stomach and perform surgery to return it to its normal position within the body. They can then permanently tack it in place to prevent a GDV from recurring.

Ascites (Fluid Accumulation)

Various medical issues can cause fluid to build up within the abdomen. This would include heart failure, liver disease, and protein-losing enteropathies.

The fluid will cause the abdomen to swell up and feel squishy. When your vet feels the abdomen, they may elicit a visible ‘fluid wave’ as the fluid sloshes about inside.

The presence of ascites is always a red flag and something that needs to be investigated urgently. Treatment will depend on the underlying cause. Typically, the fluid is not physically drained, but your pet may be given medicine to help rid the body of the excess fluid.

If your dog coughs, heart failure is more likely. Other signs that can be present include an inability to keep up when exercising, pale gums, or episodes of collapse.

With protein-losing enteropathies, your dog will generally have ongoing loose stool, which may be bloody. However, chronic diarrhoea in dogs can have many other causes.

Internal Bleeding

The presence of free blood within the abdomen can occur for a number of reasons. These include ruptured tumours (such as splenic tumours), blood clotting disorders, or toxin ingestions.

A dog may show signs, including breathlessness, weakness, pale gums, and blood in the abdomen.

Once blood is found within the abdomen, this is an emergency. The patient may need immediate surgery to stop any bleeding or urgent medical care to improve their blood clotting ability.

Organ Enlargement

If an organ such as the liver or spleen is enlarged, this can press on the abdominal muscles and lead to a bulge or swelling. The abdomen will feel quite firm, and the swelling can occur gradually over weeks or months.

A vet may be able to identify the enlarged organ by feeling the abdomen, and imaging, such as an ultrasound scan, can then be performed to assess the cause of the enlargement. Causes can include organ failure or infections.

Tumours or Masses

When an older dog presents with abdominal swelling, we would also consider tumours. This is especially true if the dog has other signs such as weight loss, vomiting, or lethargy.

In addition to imaging to identify the mass, your vet may discuss taking a sample (biopsy) in order to identify what exactly is going on.

A tumour can cause swelling due to its large size and because it can lead to fluid and/or blood building up within the abdominal cavity.

Other Causes of Swollen Abdomen

There are many other reasons we can see swelling of the abdomen, including:

• Muscle weakness due to, e.g., Cushing’s disease or chronic steroid use
• Obesity
• Pregnancy or pseudopregnancy
• A hernia
• Peritonitis
• An intestinal obstruction
• A parasite burden
• Back pain. A condition like IVDD (Intervertebral Disc Disease) can lead to a changed posture that mimics a swollen abdomen
• Pyometra in dogs (uterus infection)

Diagnosing a Swollen Abdomen in Dogs

Book an urgent vet visit if you suspect your dog’s abdomen is enlarged.

Initial Examination for Swollen Abdomen

Your vet will ask about your dog’s recent medical history and symptoms and perform a thorough physical exam. They will also want to weigh your dog to see if it has gained or lost weight since their last visit.

Diagnostic Tests for Swollen Abdomen

If your vet confirms that your dog has true abdominal swelling, they will likely recommend some tests as the next step.

Depending on their age and the other physical signs present, this may include abdominal imaging, a blood test, and a urine test.

Treatment Options for a Swollen Abdomen in Dogs

How your dog will be treated will depend on several factors, including the cause of its swelling, any co-existing medical issues, its age, and your finances. Your vet should discuss the options available so you can decide on a plan together.

Immediate Care and Stabilisation

If your dog is unstable or critically unwell, it may need to be admitted to the vet clinic. This may include the provision of oxygen, fluid drainage, surgery to remove any bleeding tumours, or the start of injectable diuretics.

Once stable, your dog should be sent home with a management plan. Initially, you may need to return to the clinic for regular tests and checkups to assess how it responds to treatment.

Treating the Underlying Cause

Each patient will receive an individual treatment plan based on their unique circumstances. This can include daily medicine, prescription diets, and/or surgical procedures.

Some dogs may be referred to specialist centres, particularly if they have more complex medical issues, such as metastatic cancer or IVDD.

Post-Treatment Care

Ongoing care will likely include check-ins with your vet and assessment of the abdomen. This may include repeated scans and further tests such as blood tests.

If your dog has had surgery, it will need consultations to assess its surgical wound as it heals. It may also have a dressing that needs to be kept clean and a buster collar to ensure it does not chew its wound.

Preventing Swollen Abdomen in Dogs

Not every case of a swollen abdomen can be prevented. However, it is within your power to keep your dog up to date with their vaccines and wormer, to neuter a female who is not going to be bred from, and to not over-feed your pooch.

For owners of large, deep-chested breeds, you may wish to discuss a surgical procedure (gastropexy) to prevent a GDV. This is sometimes done at the same time as a neutering surgery.

Get Help With Your Dog’s Swollen Abdomen

Do not hesitate to contact us to discuss any concerns you have about your dog and their health.

Our staff are here to ensure your dog gets the best care.