Bloating (Abdominal Distension) in Dogs

Key Takeaways

Abdominal distension is a symptom where a dog’s abdomen has increased in size. It may be focal, affecting only one small area, or generalized across the entire abdomen. 

• Abdominal distension can be caused by fluid or blood accumulating in the abdomen, excess fat, tumors, swelling of an organ, weakness in the muscular wall of the abdomen, and free air in the abdominal cavity

• Associated conditions range and include congestive heart failure, cancer, infections, injuries, hernias, and bowel perforation

• Diagnostics include medical imaging, abdominocentesis, blood/urine analysis, and biopsies

• Treatment depends on the underlying cause but can include surgery, antibiotics, other medication, symptomatic care, and fluid drainage

• Prognosis is varied depending on the underlying cause but all causes require immediate veterinary intervention to increase the chances of a positive prognosis

A Closer Look: What is Abdominal Distension in Dogs?

Abdominal distension is a common symptom as it is often associated with a large number of conditions. Many causes of abdominal distension are life-threatening and require immediate intervention. In these cases, other symptoms are usually present alongside the distension including pain, blood in excretions, seizures, and lameness.

It is best to seek out rapid care to determine the underlying cause.

Possible Causes

There is a large range of conditions associated with abdominal distension. The accumulation of blood, other fluids, or air in the abdominal space may produce abdominal distension. The characterization of the bloating suggests the underlying disease process. For example:

Clear fluid in the abdomen (Ascites) is associated with:

Congestive heart failure

Heartworm disease

• Liver disease

• Protein losing enteropathy

• Bacterial/Viral infections

Blood in the abdomen is associated with 

• Physical injuries

• Bleeding tumor

• Bleeding/clotting disorder

Free air in the abdominal cavity (pneumoperitoneum) is usually associated with gastric or intestinal perforation.

In addition to fluid and air accumulating in the peritoneal space, other conditions and physiological changes that can cause abdominal distension include: 

• Excess fat, such as in cases of obesity and Cushing’s disease.

• Tumors, such as abdominal tumors in the spleen/liver or visceral hemangiosarcoma.

• Swelling of abdominal organs, such as the uterus during pregnancy or infection (pyometra), the stomach during GDV or in cases of heavy intestinal parasite infestation, or the liver in cases of hepatic lipidosis

Finally, some forms of hernias also cause abdominal distension. These are caused by weakness, perforation, or congenital defects in the abdominal wall muscles.

Risk Factors

Abdominal distension can vary in severity based on a wide range of factors, including the extent of distension, whether it is acute or chronic, intermittent or persistent, localized or generalized, and progressive or stable. Regardless, with the exception of confirmed obesity or pregnancy, it is a serious and concerning symptom that requires immediate attention.

Testing and Diagnosis

After a physical examination and medical history, a number of tests can be done to determine the underlying cause of the distension:

• Medical imaging (X-rays, ultrasounds)

• Abdominocentesis

• Bloodwork

• Urinalysis

• Biopsies

Treatment varies depending on the condition causing the distension but can include;

• Drainage of the fluid

• Surgery

• Medication (diuretics)

• Antimicrobials

• Symptom management

Similar symptoms

There are not any symptoms that can be mistaken for abdominal distension.

Associated Symptoms

Other symptoms that appear in conjunction with abdominal distension are dependent on the underlying condition. Some common examples include;

Heart Disease/Congestive Heart Failure

Exercise intolerance


Cushings’s Disease

Excessive thirst

Excessive urination

• Thinning hair coat

Splenic tumor/internal bleeding



Pale gums

• Visible protrusion from the abdomen, most readily visible when lying on one side

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