Cat & Dog - Abdominal Enlargement

Abdominal enlargement is not unusual in dogs.  It can occur with obesity but there are many other causes.  For example, redistribution of fat into the abdominal cavity may occur with Cushing's syndrome (hyperadrenocorticism).  This occurs in dogs but is rare in cats.  Hypothyroidism (lack of thyroid hormone) can also result in abdominal enlargement in dogs.  This is another condition rare in cats.

Abdominal enlargement can also be due to fluid accumulation in the abdominal cavity.  This can be the result of liver disease, cardiac disease, abdominal tumours and, in cats, feline coronavirus disease (FCoV), causing feline infectious peritonitis (FIP).

Rapid onset abdominal enlargement in both dogs and cats can be the result of internal bleeding or leakage of urine into the abdominal cavity as a result of trauma, due to a fall or road traffic accident.

What is involved with diagnosis?

The first step is to take a thorough history and carry out a physical examination together with routine urine and blood tests, including haematology and serum biochemistry.  These will give an indication regarding the functioning of the liver and kidneys.

Urine analysis is helpful since it gives an evaluation of the physical and chemical properties of the sample.  These values in association with the serum biochemistry results, often point to the diagnosis.

Will additional tests be necessary?

This depends entirely upon the information obtained from the physical examination and the 'general' tests undertaken.  For example, in the case of hyperadrenocorticism (Cushings syndrome) we may have to admit the animal for a few hours in order that special blood tests can be carried out.  Hypothyroidism may be confirmed by determination of serum thyroxin (T4 tests) again involving blood samples.

If there are organ problems such as liver disease, specific tests such as serum bile acid determination may be required together with diagnostic imaging (x-rays, ultrasound), etc.

In the case of abdominal enlargement due to fluid accumulation, tests involving fluid sampling via fine needle aspiration may be necessary.  Depending on the results obtained, biopsies may be the next step.