A liver shunt in dogs (also called a portosystemic shunt, or PSS) is a serious condition that prevents blood from being properly filtered by the liver. This allows toxins like ammonia to circulate in the bloodstream, causing problems with the brain, gastrointestinal system, urinary tract, and growth.
At Oklahoma Veterinary Specialists, we regularly diagnose and treat dogs with congenital and acquired liver shunts. This article provides a comprehensive overview of liver shunts in dogs - from what causes them, to how they are diagnosed, treatment options, surgery recovery, prognosis, and frequently asked questions from dog owners.
What is a Liver Shunt in Dogs?
A liver shunt in dogs is an abnormal blood vessel that allows blood from the intestines to bypass the liver and flow directly into the body’s circulation. Normally, the liver filters toxins, processes nutrients, and supports metabolism. When this process is bypassed, toxins remain in the bloodstream and affect multiple organs.
There are two main types of liver shunts in dogs:
- Congenital liver shunt (CPSS): Present at birth. Usually a single shunt.
- Acquired liver shunt (APSS): Develops later in life as a complication of chronic liver disease and portal hypertension. Dogs can test negative as puppies and still develop an acquired liver shunt later on.
Are all liver shunts in dogs genetic?
No. Many congenital shunts are hereditary in certain breeds (Yorkshire Terrier, Maltese, Cairn Terrier, Irish Wolfhound), but acquired shunts are not genetic - they develop secondary to liver disease.
Are liver shunts in dogs congenital?
Not always. Some are congenital (hereditary, present from birth), while others are acquired.
Causes of Liver Shunts in Dogs
- Congenital causes (genetic/hereditary): A failure of fetal blood vessels (like the ductus venosus) to close after birth.
- Acquired causes: Severe liver disease or cirrhosis leading to high portal blood pressure. This pressure opens up tiny fetal blood vessels that should normally stay closed.
What causes a liver shunt in dogs?
Congenital shunts are caused by abnormal blood vessel development. Acquired shunts are caused by chronic parenchymal liver disease and portal hypertension.
Signs and Symptoms of Liver Shunt in Dogs
The signs of liver shunt in dogs can vary, but the most common include:
- Neurological symptoms (hepatic encephalopathy): disorientation, circling, head pressing, seizures, or acting “spaced out.” These often worsen after eating.
- Digestive issues: vomiting, diarrhea, poor appetite, or a dog with liver shunt who won’t eat. Some dogs have pale/yellow stool (liver shunt dog yellow poop).
- Urinary problems: blood in urine, frequent urination, or bladder stones (ammonium biurate uroliths).
- General signs: small size compared to littermates, poor growth, dull coat, or prolonged recovery after anesthesia.
What to do when your dog falls off the bed like a seizure (liver shunt)?
Contact your veterinarian immediately. Seizures are a serious complication of liver shunts and may require emergency stabilization with anticonvulsants.
How is a Liver Shunt Diagnosed in Dogs?
If your veterinarian suspects a liver shunt, the diagnostic process may include:
- Bloodwork: low BUN, low cholesterol, low albumin, microcytosis, and variable liver enzyme changes.
- Bile acid stimulation test: compares fasting and post-meal bile acid levels. Abnormal results suggest poor liver function.
- Plasma ammonia test: high fasting ammonia supports the diagnosis.
- Imaging: abdominal ultrasound, CT angiography (gold standard for mapping shunts before surgery), or scintigraphy.
What does a liver shunt fraction of 83% mean in a dog?
It means that 83% of the blood is bypassing the liver - a very significant shunt that will usually cause clinical signs.
Treatment Options for Liver Shunts in Dogs
1. Medical Management
- Lactulose: reduces ammonia absorption.
- Antibiotics (metronidazole, rifaximin, or neomycin): decrease ammonia-producing gut bacteria.
- Anticonvulsants (levetiracetam): for seizure control.
- Supplements: zinc, vitamin E, milk thistle, probiotics.
- Not recommended: cannabis treatment for dogs with liver shunts. Cannabis can be toxic and has not been proven effective.
2. Nutritional Management (Liver Shunt Diet for Dogs)
- Best dog food for dogs with liver shunt: veterinary prescription diets such as Hill’s l/d or Royal Canin Hepatic.
- Homemade dog food for liver shunt: must be formulated by a veterinary nutritionist to ensure balance.
- Protein guidelines: moderate protein restriction with highly digestible proteins (egg, dairy, soy).
- Foods to avoid: organ meats, high-protein treats.
- Safe treats for dogs with liver shunts: carrot slices, apple pieces (no seeds), prescription-friendly dog treats.
- FAQ: Is broccoli bad for dogs with liver shunt?
Broccoli isn’t toxic, but cruciferous vegetables can cause gas. Small amounts are usually safe if tolerated.
Avoid ketogenic diets. A dog liver shunt keto diet is unsafe due to high protein and fat levels, which can worsen symptoms.
3. Surgical Correction
The definitive treatment for many congenital shunts.
- Ameroid constrictor or cellophane banding: gradually closes the shunt.
- Suture ligation: immediate closure (higher risk of portal hypertension).
- Intrahepatic shunts are more complex and riskier than extrahepatic ones.
How to fix a liver shunt in dogs?
Surgery at a specialty hospital is the gold standard for congenital shunts.
Dog Liver Shunt Surgery Recovery
Recovery usually involves:
- Hospital monitoring for seizures and portal hypertension.
- A restricted diet during healing.
- Rechecks with bile acid or protein C testing.
What to expect after my dog has liver shunt surgery?
Dogs often improve gradually over weeks to months. Some may need ongoing medication or a special diet long term.
Prognosis and Life Expectancy
- Can a dog survive with liver shunt?
Yes, many dogs survive and thrive, especially with surgery.
- How long can a dog live with a liver shunt (without surgery)?
With medical management only, dogs may live months to years, but symptoms usually worsen over time.
- How long can a dog live after correcting liver shunt?
With successful surgery, many dogs live a normal lifespan.
- Can liver shunts kill dogs?
Yes - untreated shunts can lead to seizures, liver failure, or urinary complications that may be fatal.
- Putting down a dog with liver shunt:
Euthanasia may be considered if quality of life is poor and surgery isn’t an option.
Cost of Liver Shunt Surgery
FAQ: How much is liver shunt surgery in dogs?
The average cost of surgery for a liver shunt in dogs is typically $5,000–$12,000 depending on the hospital, diagnostics, and complications.
Future Directions in Liver Shunt Research
- Genetics: studies at institutions like Purdue University (dog liver shunt research) are working to identify genetic markers.
- Advanced surgery: minimally invasive techniques and interventional radiology are expanding.
- Better medical therapy: research continues into improved drugs for hepatic encephalopathy.
Final Thoughts
A liver shunt in a dog is a serious but often manageable condition. Surgery offers the best long-term prognosis for congenital shunts, while medical and dietary management can help stabilize patients.
At Oklahoma Veterinary Specialists, our board-certified surgeons and internists work together to provide comprehensive care, from advanced imaging to surgery and post-operative support.
If you suspect your dog may have a liver shunt, contact us today to schedule a consultation.
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