Liver Shunts in Labrador Retrievers: When Blood Bypasses the Liver Entirely

Normally, blood from the intestines travels through the portal vein directly to the liver, which filters out toxins, including ammonia produced during protein digestion, before that blood joins general circulation. A shunt is an abnormal vessel — present from birth in most cases (a congenital shunt) — that allows some or most of that blood to skip the liver entirely and go straight into general circulation.

The result is a buildup of unfiltered toxins, most notably ammonia, which particularly affects the brain and produces a set of symptoms collectively called hepatic encephalopathy: disorientation, staring into space, circling, or even seizures, often worse after a protein-rich meal when ammonia production spikes. Affected puppies are also frequently smaller than littermates, since the liver plays a broader role in growth and nutrient processing beyond just detoxification.

Diagnosis typically starts with bloodwork showing elevated bile acids, followed by imaging — ultrasound, CT angiography, or sometimes nuclear scintigraphy — to actually visualize the abnormal vessel and plan for surgical correction, which is the standard treatment for congenital shunts when the dog is a good surgical candidate.

No single sign confirms a shunt, but this specific cluster — especially tied to timing after meals — is what prompts vets to check bile acid levels.

If you think your Lab has liver shunts, the plan is three steps: write down what you have seen and when it started, book a veterinary appointment rather than waiting for the next flare, and take video of the behaviour or symptom before you go — the thing you are worried about rarely happens in the consulting room. Screening in the parents covers hip dysplasia, elbow dysplasia, obesity.

What the vet visit should produce is a diagnosis and a written plan, not just reassurance: what is being ruled out, what the monitoring interval is, and which signs mean you come back sooner. Ask what the treatment costs across a year rather than per visit, because that is the number that decides whether you are managing this condition or reacting to it.

Between appointments, keep a short log — dates, what you saw, what changed. It is the single most useful thing an owner brings to a follow-up, and for liver shunts it is often what separates a clear pattern from a guess.