What is a Liver Shunt (Portosystemic Shunt)?

A liver shunt, also known as a portosystemic shunt (PSS), is an abnormal connection between the portal vascular system (which carries blood from the abdominal organs) and the systemic circulation (which supplies blood to the rest of the body). In a normal pet, blood from the abdominal organs should be drained by the portal vein into the liver for filtration and detoxification. However, in animals with a liver shunt, a portion of this blood bypasses the liver and is shunted directly into the systemic circulation. This results in decreased hepatic blood flow and impaired normal liver function.

Indications:

• Congenital Shunts: Most liver shunts are congenital, meaning the dog or cat is born with the shunt. Breeds commonly affected include:
  • Miniature Schnauzers
  • Yorkshire Terriers
  • Irish Wolfhounds
  • Cairn Terriers
  • Maltese
  • Australian Cattle Dogs
  • Golden Retrievers
  • Old English Sheepdogs
  • Labrador Retrievers
• Acquired Shunts: Under certain circumstances, liver shunts may be acquired secondary to another liver problem. Acquired shunts are almost always multiple vessels and develop in response to hepatic hypertension.

Signs & Symptoms:

• Small body stature
• Anesthetic intolerance (prolonged recovery following anesthesia)
• Behavioral abnormalities (often episodic and more noticeable after eating)

Diagnosis:

• Clinical signs and imaging (such as ultrasound) help identify liver shunts.
• Blood tests may reveal elevated liver enzymes and altered bile acid levels.

Treatment Options:

1. Medical Management:
   • Dietary modifications (low-protein diets)
   • Medications (such as lactulose and antibiotics) to manage hepatic encephalopathy
   • Symptomatic treatment for associated conditions
2. Surgical Treatment:
   • Gradual closure of the shunt is considered the treatment of choice in most animals.
   • Surgical techniques include placing constrictors (metal loops) around the vessels or using coil embolization.
   • Surgical complications are rare but can be significant.

Benefits:

• Improved Quality of Life: Relief from symptoms associated with liver shunts.
• Prevention of Hepatic Encephalopathy: Surgical closure helps prevent hepatic encephalopathy (altered central nervous system function due to liver failure).

 

Remember, always consult a veterinarian for personalized advice tailored to your pet’s specific needs.