The Maltese breed, along with the Yorkshire Terrier and Wolfhound, has a 20 time greater risk of congenial liver shunts than all other breeds.
A liver shunt, also called a portosystemic shunt (PSS), is a genetic defect in which there is a problem with the vein that carries blood in and out of the liver. Normally, blood that is brought through the liver is filtered out and then sent back into the body. A shunt, which is a diversion of this flow, leads to a toxic buildup in the body.
There are two types of liver shunts seen in Maltese and other breeds:
Intrahepatic: Blood is diverted into a vessel within the liver.
Extrahepatic: Blood is diverted outside of the liver.
A shunt may be partial (some of the blood flow is blocked) or full (all of the blood flow is blocked).
In either case, this is usually a very serious condition that needs to be treated as soon as possible, as toxins quickly build up a dog's body.