Liver Shunt Screening for Puppies: Early Detection Guide

Liver shunt, also known as portosystemic shunt (PSS), is a congenital condition seen in some puppies where blood bypasses the liver, impairing its ability to detoxify and maintain vital bodily functions. This defect can lead to toxin build-up, poor growth, neurological symptoms, and if untreated, may be fatal.

This guide explains how liver shunt screening works, which breeds are most at risk, and why early detection is essential for your puppy's health and breeding decisions.

Understanding Liver Shunts in Puppies

Liver shunts in puppies occur when abnormal blood vessels divert blood from the portal vein directly into systemic circulation, bypassing liver filtration. The two types are intrahepatic (within the liver) and extrahepatic (outside the liver). While pups in utero receive filtered blood via their dam's liver, the issue emerges after birth as their own liver cannot process blood toxins properly.

The severity varies; some puppies have minor partial shunts causing minimal symptoms, while others suffer severe health risks. This condition is hereditary but not linked to a specific gene mutation, so DNA screening is ineffective. Instead, functional screening after birth is vital.

Which Breeds Are At Higher Risk?

Some breeds have a higher incidence of liver shunts, making screening especially important. The Maltese and mixed breeds like the Maltipoo are particularly prone. Other breeds frequently affected include Irish Wolfhounds, Bernese Mountain Dogs, Huskies, Pugs, Yorkshire Terriers, Labrador Retrievers, and Havanese.

For these breeds, early screening supports responsible pet ownership and breeding practices by identifying affected puppies promptly.

When and How Is Liver Shunt Screening Performed?

The recommended screening window for liver shunts in puppies is typically between 6 and 12 weeks of age. Early screening allows for timely interventions that can improve outcomes significantly.

Step 1: Bile Acid Test (Primary Screening)

This is the most specific and commonly used test:

• Fast the puppy overnight.
• Feed the puppy its usual meal.
• Collect a blood sample 90 to 120 minutes after feeding.
• Ensure precise identification of the puppy to match results accurately.
• Monitor that the puppy eats normally during the test for valid results.
• Normal bile acid levels effectively rule out a liver shunt.

Step 2: Additional Diagnostic Tests

If liver shunt is suspected or bile acid results are abnormal, vets may recommend further testing:

• Complete blood count (CBC) and liver enzyme analysis to assess liver function.
• Blood ammonia measurement, since ammonia bypasses liver detoxification in shunted blood.
• Urinalysis to check for urinary complications that may accompany liver shunts.
• Abdominal ultrasound or X-rays to visualise abnormal vessels or liver size.
• Advanced imaging such as CT or MRI for detailed anatomy when needed.

Symptoms That Should Prompt Screening

Puppies with liver shunts may display symptoms including:

• Poor growth and failure to thrive.
• Poor appetite or restricted eating habits.
• Vomiting or diarrhoea.
• Neurological signs such as seizures, head pressing, circling, or stumbling.
• Increased thirst and urination.
• Behavioural changes and lethargy.

Treatment and Prognosis

Early diagnosis through screening is crucial because treatment can greatly improve quality of life. Many liver shunts can be corrected surgically, especially extrahepatic shunts common in small breeds. Surgery often results in excellent outcomes and normal lifespan.

In cases where surgery is not possible, medical management including dietary protein restriction and medications can help control symptoms and improve wellbeing.

Promoting Responsible Pet Ownership

Screening puppies from at-risk breeds is an important part of responsible pet care and breeding. By ensuring affected puppies are identified early and managed properly, owners and breeders can reduce suffering and support the long-term health of beloved breeds.

Consult your vet if you own a puppy of a susceptible breed or notice any of the symptoms above. Early screening using bile acid testing followed by recommended diagnostics can save lives.

For prospective puppy owners looking to find puppies or purchase from reputable breeders, asking about liver shunt screening is wise, especially in prone breeds.

Summary Table: Liver Shunt Screening Essentials