Portosystemic (Liver) Shunt
Why Should I Bring my Pet to Willows for Treatment?
Willows is one of Europe’s leading small animal referral centres. Our state-of-the-art hospital is led by internationally renowned Specialists, committed to providing the highest standards of veterinary care.
Our Soft Tissue Specialists have a particular interest and extensive experience in the investigation, diagnosis and treatment portosystemic shunts.
Our team of Surgeons are supported by our multi-disciplinary team of Specialists across a number of disciplines including; Anaesthesia, Diagnostic Imaging, Soft Tissue Surgery, Internal Medicine and Emergency and Critical Care.
Willows also has a large dedicated team of Vets, Nurses and clinical support staff available 24 hours a day, every day of the year to provide the best possible care for your pet.
What is a Portosystemic (Liver) Shunt?
A shunt is a hole or small passage which moves, or allows movement of, fluid from one part of the body to another. A portosystemic shunt is a blood vessel abnormality that results in blood from the abdominal organs (small and large bowel and stomach) being diverted to the heart and bypassing the liver. The condition may be either a birth defect (congenital), or acquired. In the case of an acquired condition it is often associated with chronic disease of the liver such as cirrhosis.
Nutrients and toxins (poisons) absorbed from the intestines are usually cleared from the circulation when they are passed through the liver via the portal vein (running from the intestines into the liver). The liver stores some food for energy, uses some to make proteins and other substances, and processes any toxic chemicals to make them safe. Maintenance of a normal liver is largely determined by the blood flow through the portal vein.
The presence of a portosystemic shunt causes blood to enter the bloodstream without passing through the liver. In congenital cases this results in the development of a small liver (hepatic hypoplasia) and the progressive shrinkage of the liver (hepatic atrophy). The gradual build-up of toxins in the bloodstream often results in nervous symptoms know as hepatic encephalopathy. Affected animals may also lack the necessary substances to provide a source of energy, resulting in poor or stunted growth.
What are the Signs of a Portosystemic Shunt?
Clinical signs in congenital cases are often seen at a young age and include;
- Small stature
- Poor muscle development
- Behavioural abnormalities (walking around in circles, disorientation, unresponsiveness, a quiet demeanour, staring into space, pressing of the head against surfaces)
- Seizures
Other less common signs include
- Excessive drinking or urinating
- Apparent blindness
- Diarrhoea and vomiting
- Bladder stones
How is a Liver Shunt Diagnosed?
A diagnosis of a liver shunt should be suspected in any individual showing the clinical signs described in the previous section. A more specific diagnosis will require blood tests, including the measurement of bile acid or ammonia concentrations.
A liver shunt cannot however be definitively diagnosed by blood tests; shunting can only be found with advanced techniques such as ultrasound scans, specialised X-rays, CT scanning, MRI scanning, and/or exploratory surgery.
What Treatment is Available for a Liver Shunt?
The surgical management of portosystemic shunts can be very demanding, which along with the requirement for specialist equipment means that it is best performed by a Specialist Soft Tissue Surgeon working from a well-equipped and well-staffed referral centre.
Surgery can be performed via open abdominal (conventional surgery) or in some cases, via a small incision in the neck (coil embolization). Both procedures aim to locate the shunting vessel and close it as much as possible to re-direct its blood through the liver. In many cases, closure of the vessel must be carried out in a slow and gradual manner. This gradual closure allows the previously under-used blood vessels within the liver time to develop without producing an excessively high blood pressure within the portal vein (portal hypertension).
What can I Expect if my Pet Undergoes Liver Shunt Surgery?
Pets often remain in hospital for a few days following surgery. Our highly skilled nursing team are very closely involved in the post-operative period providing one-to-one nursing care for patients in our Intensive Care Unit.
When patients go home, instructions are provided to restrict a pet’s exercise for the first week or so following surgery. Patients will remain on medical management (prescription diet, lactulose syrup and gut-active antibiotics) for up to six weeks following liver shunt surgery. If a patient remains without any clinical signs the administration of medications is reduced and subsequently stopped.
For the majority of patients, surgery for a congenital liver shunt will result in the complete or near complete closure of the shunting vessel and the restoration of sufficient blood flow to the patient’s liver. Such patients can be expected to lead a normal life, requiring no medication and with a normal life-expectancy.
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Soft Tissue Surgery
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To assist owners in understanding more about Soft Tissue Surgery we have put together a range of information sheets to talk you through the some of the more common soft tissue conditions seen and treated by our Specialists.
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