A portosystemic shunt is an abnormal blood vessel that diverts blood around the liver instead of through it.

Because the liver never “sees” this blood, it cannot detoxify waste, regulate nutrients, or mature properly.

 

Toxins (especially ammonia) build up → neurologic signs (“hepatic encephalopathy”), poor growth, stomach/intestinal irritation, and urinary problems.

 

There are two broad types:

• Extrahepatic (outside the liver) — most common in small-breed dogs (Yorkshire Terriers, Maltese, Shih Tzu, Poodles) and many cats;

• Intrahepatic (inside the liver) — more common in large-breed dogs (not the focus of this guide).

 

Surgery or minimally invasive attenuation gives the best chance at cure or major improvement for EHPSS.

 

Medical management alone helps control symptoms but does not cure the disease. Surgery