Portosystemic Shunt

Portosystemic Shunt (PSS) 

Portosystemic Shunt (PSS), also known as a liver shunt, is a serious condition in dogs where blood bypasses the liver instead of flowing through it for detoxification. Normally, the liver filters toxins, nutrients, and waste products from the bloodstream. In dogs with a PSS, an abnormal blood vessel diverts this flow directly into the general circulation, allowing harmful substances to accumulate in the body. This can lead to neurological, digestive, and urinary complications if left untreated.

Dogs affected by Portosystemic Shunt often show neurological and digestive symptoms, such as poor growth, vomiting, diarrhea, loss of appetite, excessive thirst, disorientation, and seizures. Some may display strange behavior after eating, such as circling or head pressing, due to toxin buildup affecting the brain (a condition known as hepatic encephalopathy). Puppies with PSS may appear smaller and weaker than their littermates, and in severe cases, urinary stones or infections can also occur.

The cause of PSS can be congenital (present at birth) or acquired due to chronic liver disease. Congenital shunts are more common and are often seen in small or purebred dogs. Depending on where the abnormal vessel is located, the condition is categorized as intrahepatic (within the liver) or extrahepatic (outside the liver). Early diagnosis and treatment are essential to prevent long-term liver and brain damage.

Dog Breeds Commonly Affected by Portosystemic Shunt

Certain breeds are genetically predisposed to developing congenital Portosystemic Shunts. These include:

• Yorkshire Terriers
• Maltese
• Miniature Schnauzers
• Shih Tzus
• Cairn Terriers
• Irish Wolfhounds
• Pugs
• Dachshunds
• Havanese
• Australian Cattle Dogs

Diagnosis typically involves blood tests, bile acid tests, ultrasound imaging, or advanced scans like CT or MRI angiography to locate the shunt. Treatment depends on the type and severity of the shunt. Surgical correction is often the preferred option, allowing the abnormal vessel to be gradually closed, restoring normal liver function. In mild or inoperable cases, medical management with a special low-protein diet, antibiotics, and lactulose can help reduce toxin buildup and control symptoms.

With proper treatment and ongoing monitoring, many dogs with Portosystemic Shunt can lead normal, healthy lives. Regular veterinary checkups, maintaining a liver-friendly diet, and following your vet’s recommendations are essential for long-term management. Early diagnosis is key to improving prognosis and ensuring your dog enjoys the best quality of life possible.