Liver Shunts in Dogs
Can surface very early or can go undetected for several years

Liver shunts in dogs have two very large misconceptions; they do not always affect small breeds and they do not always affect puppies.

However, there is one thing that is not a misconception; they are extremely serious and can very easily be deadly to you dog if they are not corrected.


Liver shunts, also referred to as PSS or a portosystemic shunt, is a very serious condition.

The normal flow of blood to your dog’s liver, both to the liver and thru the liver, is either drastically reduced, or worse yet, totally absent.

In the majority of cases, this condition will affect puppies at a very early age.

If they are considered minor, they may go undetected for as long as two to three years in some cases.

Under normal circumstances, the blood that returns form your dog’s digestive tract is routed through the liver to what is called the portal vein.

The portal vein conducts blood from the digestive organs as well as the spleen, pancreas, and the gallbladder.

It will than travel through their liver, where it exits and joins the venous blood that is flowing back to the heart.

A liver shunt is a blood vessel that connects the portal vein in your dog with the main flow of blood, called the systematic blood stream.

Once this occurs, it causes the blood to bypass the liver, and if it severe enough, a puppy will not be able to thrive, or in some cases, live.


Husky eyesLiver shunts in dogs can be deadly if not controlled very early

Liver shunts in dogs are congenital, which simply means they are present at birth.

Although they seem to be more common in smaller breeds of dogs, they can affect all breeds, and come in two different forms; intrahepatic and extrahepatic.

If the shunt is intrahepatic, the blood is diverted in a vessel within the liver, if it is extrahepatic; the blood is diverted in a vessel that is around the outside of the liver.

When the liver in a fetus is not yet fully developed and is unable to function on its own, the fetal bloods supply by-passes the liver through a special blood vessel called the ductus venosus.

This vessel transports blood around the developing liver instead of going thru it.

In addition, because the fetal liver is still not fully functional, the blood of the fetus is carried from its developing body to the mother and back again through the umbilical cord.

The umbilical cord in the mother is made up of three major parts; the umbilical artery, the umbilical vein, and the placenta.

It is in the placenta where the blood of the fetus and the mother actually interact, however, what is amazing about this process, is the fact that they never actually comingle.

The mother’s nutrients are than passed from her system to the fetus and waste products from the fetus are taken in by the mother.

From there they are than processed through her kidneys and liver.

To basically sum this process up, the mother’s liver serves the functions of the liver of the fetus as it is still developing.

It is when the puppy is born, that this condition can occur.

Once the puppy is born, the umbilical cord is no longer functional.

It is shortly after this that the ductus venosus will do three things; it contracts, constricts, and then closes.

Once this process is done and the vessel closes, the puppy’s blood is forced to pass through its own liver.

If this vessel fails to close, the shunting process begins in one of the two forms.

If the blood is shunted around the liver instead of to and though it, the liver will not preform properly.

One of the first things that will develop is that the removal of metabolic wastes such as ammonia cannot take place.

As a result, their levels start to rise, placing the health as well as the life of your dog at risk.

This is where liver shunts in dogs either surface right away, or remain hidden for several months or even years.

Everything will ride on the degree in which the blood is being shunted around the liver, and this will all depend on the actual size of the shunt.

The actual extent of the shunting will be different in every dog, regardless of their breed.


The symptoms of liver shunts in dogs will be directly related to the extent of the blood that is bypassing the liver.

If only 5 or 10 percent of the blood is being shunted, your dog will show only very mild symptoms or in some cases, may show none at all.

It is these of types of cases that the shunting goes unnoticed for long periods of times.

However, as the amount of blood that bypasses your dog’s liver increases, the symptoms will be much more obvious and easy to notice.

The first signs to watch for are your puppy or dog becoming very lethargic as well as appearing to grow very slowly.

When these signs do start to surface, they are usually accompanied by vomiting, diarrhea, or just the complete opposite; constipation.

As the shunting continues or worsens, the next set of symptoms is usually increased thirst that is naturally flowed by increased urination.

However, all of these symptoms with Liver shunts in dogs may appear to be very common to most owners, especially with puppies.

But the next symptom that you will see is anything but common; excessive drooling.

As any dog owner understands, drooling is quite common in large breeds of dogs, but even large breeds will not drool excessively as a puppy or young dog.

If drooling does occur with any of the other symptoms, it is a real warning sign that something is very wrong in your puppy or young dog.

If it a small breed, it is even more of a warning sign.

However, there are three more symptoms that may surface as the liver shunts in dogs increase.

If your dog suddenly starts to walk in circles, it is not a cute gesture; it is a severe warning sign that will require immediate medical attention as the shunting has now become life threatening.

If your dog is not immediately treated, there are two more symptoms that they may show you; a seizure that is than followed by the very sudden death of your dog.

This is a very serious condition, and the only way to prevent the last two symptoms is to catch it as early as you can.


Liver shunts in dogs are extremely serious, even if they are very mild.

The reason for this is that even dogs with very mild symptoms face danger every day as they grow and increase in size.

It is important to remember that their blood is by-passing their liver and the larger they become, the more at risk they are because they are producing more metabolic waste.

Your dog has a very little chance at a normal life unless this condition is corrected.

Most all veterinarians will choose one method of treatment; identify the abnormal blood vessel or vessels, and then surgically closing them as soon as possible.

However, this is considered to be a very difficult and complicated surgery, so you will want to get the most seasoned professional you can find to preform it.

There may be some cases where a few dogs can be treated with protein restricted diets as well as medications, but this is extremely rare.


Liver shunts in dogs and the overall prognosis will all depend on the size of the shunts, the location, and how early they are caught.

It can be an expensive process if it is a severe case, and may become a very difficult decision.

However, most dogs will not survive without the surgery.

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