Dog Liver Shunts Explained by Rhiannon Koehler, DVM, MPH and Reviewed by Brittany Kleszynski, DVM, Published on April 25, 2023, and Last Reviewed on April 30, 2025. Shares on Facebook, Twitter, Email, or Print available.
In the canine kingdom, the liver plays a pivotal role in keeping Fido ticking, detoxifying the blood as it absorbs nutrients and potentially harmful substances. But when this detoxification process is bypassed due to a liver shunt, trouble brews for our four-legged friends. Here, we dive into the nitty-gritty of liver shunts in dogs, from their causes and symptoms to potential treatments.
The Lowdown on Liver Shunts (a.k.a. Portosystemic Shunts)
To grasp the essence of liver shunts, imagine the highway system in your dog's body. The vessels carrying blood from the intestines, spleen, and pancreas to the liver make up this intricate freeway network. When a vein is abnormally connected in such a way that blood is diverted away from the liver, it's called a portosystemic shunt. Essentially, blood takes a detour around the liver, bypassing its detoxification duties. These shunts can manifest at birth (congenital) or develop later in life (acquired).
The Birth-Issue Shunt (aka Congenital Shunt)
When a dog is still in their mother’s womb, they don't need the liver for detoxification as they aren't eating anything. During this time, they have a large shunt called the ductus venosus that allows blood to bypass the liver. This vessel is supposed to collapse after birth. However, if it remains open or if the puppy develops another abnormal venous connection while growing inside its mother, it results in a congenital liver shunt. Inherited genetics play a part, but congenital liver shunts are considered a complex trait, meaning they're not simply inherited from a dog's parents.
Breeds at higher risk of congenital liver shunts include Yorkshire Terriers, Old English Sheepdogs, Irish Wolfhounds, Cairn Terriers, Maltese, Labrador Retrievers, Miniature Schnauzers, and large breeds like St. Bernards that commonly experience single intrahepatic shunts.
The (Possibly Un)Welcome later-in-Life Shunt (a.k.a. Acquired Shunt)
Acquired shunts typically crop up later in a dog's life and are often associated with liver conditions that increase pressure in the liver's vessels, such as cirrhosis. They can also stem from trauma or ongoing liver problems. What’s more, any dog can be affected by these shunts, regardless of breed or age.
On the Lookout for Liver Shunt Symptoms
Dogs with large congenital liver shunts will develop symptoms early, while those with small, less severe shunts might exhibit symptoms later in life. Warning signs of a liver shunt in dogs may include:
- Stunted growth
- Poor muscle development
- Odd behaviors (such as appearing disoriented, staring into space, walking in circles, or pressing head against walls) that sometimes manifest after meals
- Seizures
- Excessive drinking and urinating
- Vomiting
- Diarrhea
- Prolonged recovery after receiving anesthesia
The symptoms of acquired shunts are similar to those of congenital shunts but are often seen in middle-aged or older canines. In addition, dogs with acquired shunts might also display signs of the underlying disease causing portal hypertension, such as jaundice (yellow gums and eyes).
Unmasking a Liver Shunt: Diagnosis and Treatment
To diagnose a liver shunt, your veterinarian will start with a physical exam and routine lab work. Based on these results, they might recommend additional tests, including bile acid tests, X-rays, ultrasounds, CT scans, MRIs, exploratory surgery, or liver biopsies.
Treatment for congenital liver shunts largely depends on the situation. If your dog is experiencing severe symptoms, doctors may initially stabilize them with special diets, medications, lactulose for reducing the absorption of toxins, and rectal enemas to remove toxins from the intestines before they're absorbed. After stabilizing your pup, the shunt will typically be closed surgically using a metal band known as an ameroid constrictor. This innovative device contains a milk protein core that absorbs fluid and gradually swells, closing the shunt over time. The success rate for this treatment tops 95%, and most dogs recover within 4-8 weeks.
In cases where medical management is acceptable, a protein-restricted diet, lactulose, and possibly antibiotics to reduce toxin-producing bacteria might be recommended.
Liver supplements, like milk thistle and SAM-e, may help but won't be sufficient to replace surgery or medical management.
The cost to treat liver shunts in dogs can vary widely, anywhere from $2,000 to over $10,000, depending on factors like your dog's size and the type of shunt.
In conclusion, while congenital and acquired liver shunts differ in their origins and treatment options, both can pose significant health challenges for our canine companions. Prompt diagnosis and appropriate treatment can help ensure a happy, healthy future for your furry friend.
- Understanding pet health is crucial in detecting medical-conditions like liver shunts, and science plays a pivotal role in this field, especially in the diagnosis and treatment of such conditions.
- In the realm of health-and-wellness for dogs, liver shunts are a significant concern, particularly in breeds like St. Bernards, as they are more prone to congenital shunts, and any dog can be at risk for acquired shunts later in life, causing various symptoms and potentially serious health issues.
