Portosystemic Shunts and Your Pet

Portosystemic shunts (PSS), or liver shunts, are an abnormality in a pet’s blood flow through the liver. The liver normally filters toxins and impurities from the bloodstream. In a pet with a PSS, though, an extra blood vessel allows the blood to skip circulation through the liver. This prevents proper cleansing of potentially harmful substances from the body.

As you can imagine, a PSS can result in some pretty serious consequences. At Oakland Veterinary Referral Services, we are able to accurately diagnose and treat liver shunts medically as well as surgically.

What Causes Portosystemic Shunts in Pets

There are two primary ways a pet may be affected by a portosystemic shunt. A PSS may be:

Congenital – A congenital problem is one a pet is born with. It is thought that PSS may be inherited and results from the failure of a normal fetal blood vessel to close off after birth. These are often diagnosed prior to one year of age.

Acquired – A liver shunt may develop when there is a problem with the liver in which the organ cannot handle its normal blood flow. In this case the shunt is the body’s effort at trying to prevent liver failure.

Symptoms of a Portosystemic Shunt

Portosystemic shunts are most commonly a canine problem, however they can be seen in cats as well. They can affect any age or breed of pet. Shunts contained within the liver (intrahepatic) are most often seen in larger dog breed while shunts outside of the liver are often seen in small breed dogs.

In pets with liver shunts, symptoms arise from the inability of the liver to function normally. They can be nonspecific and often wax and wane. Common signs of a PSS include:

• Poor growth
• Digestive problems (Drooling, vomiting, diarrhea, anorexia)
• Behavioral changes (Depression)
• Neurological signs (Loss of balance, walking in circles, blindness)
• Seizures

Diagnosis of Pet Liver Shunts

We are often able to diagnose a PSS in a pet based on his or her clinical signs and lab work. A liver function test, called a bile acids test, is what is typically performed for a diagnosis. Once a diagnosis is made, though, it is important for us to locate where the liver shunt is, and how the liver looks; which will involve more-advanced testing.

In many pets, abdominal ultrasound can be used to obtain this information. In some pets, however, more intensive techniques will need to be used. These include contrast portography (in which dye is used to visualize the vasculature in the region of the liver) or nuclear scintigraphy (in which radioactive substances are used to show the details of the liver).

Treating Pet Portosystemic Shunts

Luckily for pets with a PSS, there are some very effective treatments available. There are two primary approaches for treating liver shunts:

Medical treatment of PSS – Medical management of liver shunts is aimed at easing the workload of the liver and symptomatically managing symptoms. This includes the use of a specialized diet, antibiotics, and a medication called lactulose. Anti-seizure medications may also be used. This approach is most often used for pets with acquired shunts or those shunts that are not good surgical candidates.

Surgical treatment of PSS – Surgical treatment of portosystemic shunts is often very effective and considered the gold standard for treatment. During this procedure, it is attempted to mostly or entirely close off the shunt. This is done by one of our boarded veterinary surgeons with either an ameroid ring or cellophane band placed around the blood vessel. These are designed to slowly close over a 4-6 week period.

Diagnosis and treatment of a portosystemic shunt can be an involved process. Most pets, however, have a good prognosis, particularly if surgical treatment can be pursued. OVRS is able to provide advanced veterinary care for our patients to provide the best possible outcomes. We are proud to be able to offer help for pets with liver shunts, as well as counseling and relief for their owners.