Yorkshire Terriers are known for being tiny, bright, and full of personality. Their small size, however, can make subtle health changes easy to dismiss. A puppy who stays unusually small, seems disoriented after meals, or has repeated stomach or urinary problems may need more than time to “grow out of it.”
One condition Yorkie families should understand is a congenital portosystemic shunt—often shortened to a liver shunt. It is not simply a weak or irritated liver. It is an abnormal blood vessel that allows blood from the digestive tract to bypass the liver instead of being filtered through it.
Because the liver is bypassed, toxins such as ammonia can circulate through the body and affect the brain. The liver may also receive fewer nutrients and growth signals, which can interfere with normal development.
recognition matters. Signs may come and go, and routine liver enzyme values alone do not rule out a shunt.
Understanding the condition
What a Liver Shunt Actually Does
In a healthy dog, blood from the stomach and intestines travels through the portal vein into the liver. The liver processes nutrients, regulates energy, and removes or transforms substances that should not enter the general circulation unchanged.
With a portosystemic shunt, some or most of that blood takes an abnormal shortcut into the systemic circulation. A congenital shunt is present from birth and is usually a single abnormal vessel. Small breeds, including Yorkshire Terriers, are more likely to have a shunt outside the liver, called an extrahepatic shunt.
Yorkies can also be affected by hepatic microvascular dysplasia, a microscopic blood-vessel disorder that can produce similar laboratory findings and symptoms. A dog may have one condition, both conditions, or abnormal test results without obvious outward signs. That distinction matters because there is no single large vessel to close surgically in microvascular dysplasia.
Possible warning signs
A Shunt Can Affect More Than the Stomach
Signs vary widely and may be intermittent. Some become more noticeable after a protein-containing meal, when the body is processing nutrients and producing more ammonia. Contact a veterinarian promptly if a puppy or dog shows any concerning pattern, especially neurological changes.
A dog who is disoriented, head pressing, unable to stand, temporarily blind, collapsing, or having a seizure needs urgent veterinary care. Do not wait for a scheduled appointment or try to treat the episode with a diet change at home.
Finding the cause
How Veterinarians Diagnose a Liver Shunt
Diagnosis usually begins with the dog's history, a physical exam, blood chemistry, a complete blood count, and urinalysis. Findings can include low blood urea nitrogen, low albumin, low glucose, small red blood cells, or ammonium biurate crystals in the urine, but no single routine result confirms every case.
A veterinarian may order fasting and post-meal bile acid tests or an ammonia test to evaluate how effectively the liver is handling blood from the digestive system. Abnormal results show that more investigation is needed; they do not, by themselves, locate a shunt or reliably distinguish a large shunt from microvascular dysplasia.
Imaging is used to find the abnormal vessel and plan treatment. Depending on the dog and the specialist, this may include abdominal ultrasound, CT angiography, nuclear scintigraphy, or contrast portography. A liver biopsy may be recommended when microvascular dysplasia or another liver disorder remains a concern.
Diet requires balance
Does a Yorkie With a Shunt Need a Low-Protein Diet?
Sometimes—but “feed as little protein as possible” is not safe general advice. Puppies need adequate protein and calories for growth, and adult dogs need protein to maintain muscle and support healing. Severe or unnecessary restriction can create new problems.
Dogs showing hepatic encephalopathy may benefit from a veterinarian- directed protein-modified diet. The amount, digestibility, and source of protein are tailored to the dog's symptoms, age, body condition, and laboratory results. Some dogs tolerate dairy or high-quality vegetable protein better than certain meat proteins, but a complete prescription plan matters more than any single ingredient.
The goal is to provide the highest amount of good-quality protein the dog can tolerate without triggering neurological signs—not to remove protein indiscriminately. A veterinarian or board-certified veterinary nutritionist should guide the plan, especially for a growing puppy.
Stabilizing the patient
Medical Management Can Control Toxins and Symptoms
Medical treatment is often used to stabilize a dog before surgery, to manage dogs who are not surgical candidates, or to control symptoms while advanced testing is completed. A veterinarian may prescribe lactulose to reduce intestinal absorption of ammonia, along with an antibiotic that changes ammonia-producing intestinal bacteria.
Treatment may also address dehydration, low blood sugar, nausea, infection, urinary stones, seizures, or other complications. Medication choices and doses must be individualized. Products that seem routine can behave differently in a dog whose liver is not receiving normal blood flow.
Medical management can improve comfort and quality of life, but it does not close a congenital shunting vessel. Symptoms may return if medication or diet is stopped, and some dogs remain at risk for progressive problems.
Correcting the abnormal vessel
Surgery Offers the Best Long-Term Chance for Many Dogs
When a single congenital shunt can be safely corrected, surgical attenuation is generally preferred for long-term outcome. Specialists often use a device or material that closes the vessel gradually, giving the underdeveloped portal circulation time to adapt to increased blood flow.
A shunt cannot always be fully closed at the first procedure, and surgery has real risks, including portal hypertension, low blood sugar, and postoperative seizures. Careful imaging, experienced surgical planning, hospitalization, and follow-up testing are essential.
Prognosis depends on the shunt's anatomy, whether complete closure is achieved, the presence of additional liver abnormalities, and how the dog responds after surgery. The American College of Veterinary Surgeons notes that surgery is associated with a better chance of long-term survival than medical treatment alone for congenital portosystemic shunts.
The Yorktown Difference
Take Unusual Patterns Seriously
A Yorkie can be tiny and still be healthy. What matters is the pattern: growth, appetite, muscle, energy, digestion, urination, behavior, and recovery from ordinary stress. Repeated episodes deserve answers, even when the dog seems normal again between them.
Families should document what happened, when it occurred, what the dog had eaten, how long the episode lasted, and any video that can be safely recorded. That information can help a veterinarian recognize a pattern that may not appear during a short examination.
Education cannot replace veterinary testing, but it can help a family know when to ask the right question: could this be a liver shunt?
This article is for education and awareness. Dr. Terri Widdick is a Doctor of Physical Therapy and pet advocate, not a veterinarian. It is not a diagnosis, treatment plan, or substitute for veterinary or emergency care. Never change a dog's protein intake or medication without veterinary guidance.