Reviewed by: Paula Simons, DVM
Has your dog been diagnosed with a liver shunt? It can be a confusing topic, but we’ve worked hard to make it easier to understand.
Most dogs improve almost immediately with the proper treatment. Unfortunately, other dogs aren’t that lucky. The reasons for this are explained in detail in this post.
We’ll explain the impact a liver shunt has on small breed dogs (who tend to develop extrahepatic shunts) versus large breed dogs (who tend to develop intrahepatic shunts).
Confused? Don’t worry. Everything you need to know is fully explained in this post. We’ll explain how a liver shunt is diagnosed, options for medical management, and life expectancy.
WHAT IS A DOG LIVER SHUNT?
The quick definition of a dog liver shunt is essentially an extra passageway not connected to another structure in the body.
This extra passageway (shunt) prevents essential nutrients, hormones, and waste material from entering the liver. They are sometimes referred to as a hepatic shunt or liver shunt.
Before puppies are born, they have what’s called the ductus venosus. This vein acts like a highway to carry blood through the liver to the heart. Once the puppy is born, the ductus venosus is no longer required.
In most cases, that first intake of breath triggers systemic circulation changes in the body and the ductus venosus closes automatically.
When the ductus venosus doesn’t close after birth, a liver shunt develops. That liver shunt causes blood to move around the liver instead of through it. This is considered a congenital birth defect
The Liver: A Matter of Life and Death
The liver plays a major role in the health of animals and people. The developing fetus develops a temporary vein in order to make sure the liver works effectively.
This extra vein is known as a portal vein. It’s responsible for moving blood through the liver. The blood has to circulate through the liver in order for toxins and byproducts to be removed.
When puppies are born, it’s that first intake of breath that starts the circulatory process.
If a liver shunt develops, it diverts blood around the liver. This means that toxins and byproducts are not being effectively filtered out of the body.
Dogs with liver shunts have increased bile acids in their system. The reason for this is because bile acids are produced in the liver and stored in the gall bladder between meals. In a healthy dog, the bile acids are released into the intestines where they break down and absorb fats. The portal system pulls the bile acids back into the liver for detoxification. A healthy liver will reabsorb the bile acids and store them.
Unfortunately, if the bile acids can’t make it back through the liver, they’re forced to go in a different direction. Increased bile acids wreak havoc on the dog’s gastrointestinal tract.
The Two Types of Dog Liver Shunts
There are 2 types of liver shunts that dogs can develop. The first one is acquired at birth and the second can develop later in life due to liver disease.
Congenital Portosystemic Shunts (Congenital PSS)
This type of shunt is the most common in puppies. Dogs are usually around 1 year of age when they are diagnosed but can range from 6 months to 8 years of age. In some dog breeds it’s caused by genetics.
See the list of commonly affected dogs further into this post.
Acquired Portosystemic Shunts (Acquired PSS)
These shunts develop due to high blood pressure within the veins that connect the digestive tract to the liver. A common cause of this type of shunt is due to primary liver disease. Older dogs are more likely to experience symptoms than younger dogs.
Breeds More at Risk of Congenital Liver Shunt
Congenital shunts make up approximately 80% of all cases. In some cases, genetics are the cause. In other types of breeds, it is suspected. The following are examples of dogs who may be more prone to congenital liver shunts:
- Australian Cattle Dogs
- Australian Shepherd
- Beagles
- Bichon Frise
- Cairn Terriers
- Dachshund
- Dandi Dinmont Terrier
- German Shepherd
- Golden Retriever
- Havanese
- Irish Setter
- Irish Wolfhounds
- Labrador Retrievers
- Lhasa Apso
- Miniature Schnauzer
- Old English Sheepdog
- Pekingese
- Samoyed
- Sheepdog
- Shih Tzu
- Toy Poodle
- Miniature Poodle
- Yorkshire Terriers
Liver Shunts in Large Breed Dogs
According to Dr. Phil Zeltzman, DVM, DACVS, CVJ, larger dog breeds tend to have a shunt inside the liver. This is called an intra-hepatic shunt.
Shunts inside the liver are much more difficult to fix. They require the skillset of a highly experienced board-certified surgeon.
This type of surgery can be expensive. Please refer to the Frequently Asked Questions below.
Liver Shunts in Small Breed Dogs
Small breed dogs tend to have extrahepatic shunts (blood vessels outside the liver). Extrahepatic shunts are easier to treat via surgery than intrahepatic shunts.
For the majority of dogs with extrahepatic shunts, surgery offers the best chance for a lengthy, healthy life. The survival rate is over 95% when an ameroid constrictor is implanted.
An ameroid constrictor is a device used to gradually close the shunt vessel over several weeks.
How Liver Shunts in Dogs are Diagnosed
If a dog or puppy experiences some of the symptoms noted further into this post, a veterinarian may suspect a liver shunt. To diagnose the condition, some tests may be required. Diagnostic tests may include:
Physical examination.
Physical examinations are usually pretty quick. The veterinarian may look in your dog’s eyes, ears, and mouth. Sometimes the dog’s temperature is taken.
The veterinarian may do a pat down to check for any signs of physical pain or new lumps and bumps.
Complete Blood Count
A complete blood count can help the veterinarian determine whether your dog has underlying liver disease.
Abdominal Ultrasound (aka abdominal radiographs)
This type of x-ray may be useful in allowing the veterinarian to see where the shunt is located.
Liver Function Tests
Liver chemistries help determine the health of your dog’s liver by measuring protein levels, liver enzymes, and bilirubin in the blood.
CT Scan
A CT scan is just another way the doctor may be able to find the location of the shunt.
Bile Acid Test
The veterinarian may ask that your dog not having anything to eat for 12 hours before performing this test. This includes any kinds of treats or even chew toys.
The reason for this is to give the liver time to retrieve any bile acids remaining in the blood stream.
A blood sample is taken before eating. This is called the resting sample. From there, a small meal of canned food is given to the dog. Two hours after the meal another blood sample is taken.
Bile acid levels are then tested on both blood samples for comparison.
Clinical Signs of Liver Shunts in Dogs
- Slow or lowered growth rate
- neurological signs including behavioral changes
- vomiting (may contain blood)
- bloody diarrhea
- difficulty urinating
- blood in the urine due to the formation of bladder stones
- weight loss
Keep in mind that the signs noted above could be related to a number of other conditions. If your puppy or older dog is experiencing any of these symptoms, it’s important to have him/her seen by a licensed veterinarian.
Treating Liver Shunts in Dogs
Dogs with liver shunts are usually treated with special diets and medications.
These help to reduce the amount of toxins being produced in the body. In severe cases, intravenous fluids may be required to stabilize blood sugar.
Sometimes an enema is given to help remove intestinal toxins. This prevents them from being reabsorbed into the body.
If your dog is having seizures due to the liver shunt, he/she may be given diazepam (brand name Valium) to stop them.
Diet Change
Diet change involves reducing the amount of protein the dog ingests. Food should be high-quality with highly digestible proteins. Dogs with multiple acquired shunts will need to be managed on a protein-restricted diet for life.
Diet and medication do not fix the blood vessels in the liver, they simply reduce the symptoms so the pet can have a more normal life.
Clinical Nutrition Service
Feeding pets with liver shunts
Best Food Choices for Dogs with Liver Shunts
Dogs with shunts may have trouble metabolizing protein. Once the body breaks the protein down, the dog has trouble getting rid of the waste products. This causes neurological signs called “hepatic encephalopathy”.
Signs of hepatic encephalopathy include:
- dullness
- disorientation
- difficulty walking
- behavioral changes
- possible seizures
The amount of protein that works for your dog could be different than what another dog requires. If your dog happens to have signs of hepatic encephalopathy, he/she will require medication to help increase protein tolerance.
A good diet is usually one that is lower in protein, but still has enough to aid normal functioning. Before starting your dog on any kind of “prescription diet” or “therapeutic diet”, be sure to check with the veterinarian.
The reason for this is because some diets are lower in protein but still might not be suitable for your dog. For example, diets designed for dogs with kidney disease have lower protein levels. Unfortunately, they might be deficient in phosphorus. A dog with healthy kidneys needs that phosphorus.
Royal Canin – Hepatic Diet
Assuming you’ve already cleared it with the vet, consider shopping at Chewy.com for specialty diets. The link(s) below is an affiliate link. That means that if you click on the link and make a purchase, I may earn a small commission.
Two good options include the wet and dry version linked below. These links will bring you to the chewy website.
Royal Canin Veterinary Diet Adult Hepatic Loaf Canned Dog Food
Administering Lactulose
This sugar can be administered to change the pH level in the large intestine. This decreases the absorption of ammonia and other toxins. Dogs with multiple acquired shunts will need to have lactulose administered for life.
Antibiotics
Sometimes antibiotics are used to change the bacterial culture in the intestines. This helps to reduce the overgrowth of intestinal bacteria.
Surgery
If your dog is diagnosed with extrahepatic PSS (the shunt has developed outside the liver) surgical correction is often prescribed. This offers your dog the best prognosis overall.
Surgery involves the use of a device known as an ameroid constrictor. The veterinary surgeon implants a metal band with an inner ring of casein (the protein found in milk).
Once implanted, the device absorbs normal abdominal fluid. Gradually, the device swells and presses on the shunt.
This helps to create scar tissue and close the shunt. It could take three to four weeks for it to work.
The survival rate for dogs being treated using the ameroid constrictor is over 95%. Other types of surgical intervention can involve the placement of cellophane bands or a clot-inducing device.
Life Expectancy of a Dog with a Liver Shunt
Life expectancy depends on a few things including whether the dog has an extrahepatic shunt (located outside of the liver) or an intrahepatic shunt (located inside the liver).
Luckily, with the right treatment and care, many dogs will go on to live a normal, healthy life. The most important thing here is quality of life.
Quality of life in dogs can be assessed at the Quality of Life Scale for Dog Owners.
FREQUENTLY ASKED QUESTIONS
Is a Liver Shunt Curable?
Liver shunts in dogs are not a disease but a condition. This condition can be managed through medication and/or surgery in most cases.
What Should Dogs with Liver Shunts Eat?
Your veterinarian will recommend the best diet for your dog. Generally speaking, dogs with liver shunts follow a diet with enough protein to fulfill dietary requirements, but no more.
Can Dogs Die with a Liver Shunt?
Severe cases of liver shunts in dogs may result in a lower life expectancy. Many dogs, however, will recover quickly with appropriate treatment.
Can You Prevent Liver Shunts in Dogs?
There is nothing you can do to prevent liver shunts in dogs.
How Much Does It Cost to Fix a Liver Shunt in Dogs?
The cost to repair an intra-hepatic shunt (inside the liver) can range from $2000 to $12,000. Factors that affect price include:
- medications
- prescription diets
- length of hospitalization
- length of surgery (more shunts to repair will take more time)
- location of clinic (rural vs urban)
- travel to a qualified surgeon (hotels, gas, food, etc.) for people who live in rural areas
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Summary
A portosystemic shunt in dogs is an abnormal connection between the portal vascular system and systemic circulation. There are 2 types of shunts including congenital and acquired.
There are 2 categories of shunts that include extrahepatic (outside the liver) and intrahepatic (inside the liver). Although there is no cure, the condition can be managed through medication and surgery in most cases.
SOURCES:
Works Cited
Portosystemic Shunt in Dogs | VCA Animal Hospital. (n.d.). Vca. Retrieved September 20, 2022, from https://vcahospitals.com/know-your-pet/portosystemic-shunt-in-dogs
Ameroid Constrictor Manufacturer | Research Instruments NW. (n.d.). RINW. Retrieved September 20, 2022, from https://researchinstrumentsnw.com/