Canine Vacuolar Hepatopathy in Dogs

Canine vacuolar hepatopathy is a disorder of the liver in which small fluid-filled cavities referred to as vacuoles develop in the liver of your dog. Although the vacuoles in the liver are most often filled with glycogen, a polysaccharide that provides carbohydrate storage for most animals, they can also be filled with fat, water, or waste products. The primary treatment for this disorder is the treatment of the underlying cause. Canine vacuolar hepatopathy without a clear cause usually ends up being benign. However, regular monitoring of the liver should take place to ensure prompt action if related disorders develop.

Vacuolar hepatopathy is a disorder of the liver characterized by small fluid-filled cavities called vacuoles that reside within the cells of the liver.

This condition itself often does not have any visible symptoms unless the liver starts to fail, however, a significant number of the dogs that develop hyperadrenocorticism, or Cushing’s Syndrome, also develop vacuolar hepatopathy due to the increase in glucocorticoids. Symptoms of hyperadrenocorticism can include:

• Abdominal enlargement
• Excessive thirst
• Excessive urination
• Hair loss
• Increased appetite
• Increased panting
• Thin skin
• Urinary tract infections

Types

There are several breeds of dog who are somewhat prone to canine vacuolar hepatopathy due to either a predisposition for hyperadrenocorticism, also known as Cushing’s disease or predisposition to developing high levels of cholesterols or triglycerides, known as hyperlipidemia. 

Breeds prone to hyperadrenocorticism:

• Beagles
• Boston Terriers
• Boxers
• Dachshunds
• Jack Russell Terriers
• Poodles
• Scottish Terriers
• Staffordshire Terriers
• Yorkshire Terriers

Breeds prone to hyperlipidemia, due to increased levels of triglycerides:

• Brittany Spaniels 
• Miniature Schnauzers

Due to increased cholesterol levels:

• Briards
• Dobermans
• Great Pyrenees
• Rottweilers
• Rough-coated Collies
• Shetland Sheepdogs

• Adrenal abnormalities - Enlargement of the adrenal glands as well as increased production levels of progesterone can cause vacuoles to form
• Genetics - Certain breeds are more likely to develop canine vacuolar hepatopathy than others due to a predisposition to either Cushing’s syndrome or high levels of lipids in the blood
• Hyperadrenocorticism (Cushing’s Syndrome) - This disease causes an increase in glucocorticoids in the from either the pituitary gland or from the adrenal glands
• Hyperlipidemia (primary) - Dog breeds predisposed to elevated lipids in the blood are more likely to develop canine vacuolar hepatopathy that includes fat or lipid-filled vacuoles
• Steroid use - Dogs who use steroid treatment for allergies or itchy skin are more prone to developing vacuolar hepatopathy
• Stress - Systemic disorders and diseases that are associated with stress, such as chronic pancreatitis, severe dental disease, and hypothyroidism, may contribute to the formation of vacuoles of the liver

As dogs that have canine vacuolar hepatopathy are generally asymptomatic except for the symptoms of the underlying disorder, the disorder is usually caught due to testing for other disorders. Standard blood tests for dogs include a complete blood count and a biochemistry profile, and these tests will show an increase in alkaline phosphatase (ALP), a liver enzyme. Your veterinarian will perform a complete physical analysis including urinalysis at this time, checking for an enlarged liver and urinary tract infections, as well as determining if any other disorders are occurring concurrently.

It is important to inform your dog’s doctor about any medications or supplements your dog is taking as these can contribute to the formation of vacuoles and may need to be reassessed. Imaging of the liver by radiograph or ultrasound will show a “swiss cheese” appearance to the liver due to the vacuoles, but the definitive diagnosis has to be made based on a liver biopsy as other necroinflammatory disorders of the liver may show the same clinical signs as vacuolar hepatopathy.

Determining and treating any underlying conditions such as Cushing’s disease, a reaction to steroids, or hyperlipidemia, is the primary focus of therapy for vacuolar hepatopathy. It is essential with this disorder to thoroughly re-examine all of the medications and supplements that are being given to your pet. Steroids may either cause or exacerbate the formation of vacuoles, and holistic and herbal treatments should be checked for anything that may have a stimulating effect on the adrenal glands or pituitary gland.

Medications that may contribute to the further formation of vacuoles should be discontinued and replaced with an alternate treatment. Your veterinarian is also likely to recommend a change in the diet for your dog, which will depend on the underlying cause of the disorder. Protein should not be restricted, but in the case of lipid-filled vacuoles, a fat restricted diet may be recommended. Vitamins and antioxidants will be added to your dog’s daily regimen, and in some cases, hepatoprotective medications may be prescribed.

Prognosis for this disorder is highly variable and is based mostly on the underlying cause. If the cause of the disorder is caused by medications, the cessation of the medications will often result in a complete reversal of the disorder within just a few weeks. Some dogs with this disorder may continue to have unimpeded liver function and never show any outward symptoms of vacuolar hepatopathy, but others may develop progressive dysfunction of the liver or hepatocellular carcinoma. Dogs who have been diagnosed with canine vacuolar hepatopathy should have the functionality of the liver regularly monitored to ensure that changes are promptly addressed.