Canine liver shunts are also called portosystemic shunts or portal caval shunts and are potentially deadly. In a normal puppy foetus, the mother's liver filters out the unborn puppy's body toxins. To help the mother's liver do this essential performance, veins connecting the intestines to the liver are closed but veins around the liver are open. These are shunts.
The liver acts to filter many toxic chemicals from a dog's diet, including ammonia. In a healthy dog, blood flow from the intestines goes directly to the liver in order for the liver to filter out the toxic chemicals. But if a dog has a shunt, it has a particular vein that bypasses the liver completely so that the toxins are not removed from the body.
According to Dog Owners Home Veterinary Handbook, there are two ways dogs can develop liver shunts. One is damage from cirrhosis. But the most common reason is that they are born with it. Breeds that are most prone to liver shunts are miniature schnauzers, Maltese, Irish Wolfhounds and Yorkshire terriers.
The symptoms of liver shunts in dogs vary depending on how many shunts the dog has. Symptoms can range from seizures, vomiting, diarrhoea or constipation, excessive drooling, coordination problems and urinating far for frequently than normal. The first symptom is that the puppy is not growing as fast as it should be. However, some puppies do not begin showing symptoms until they are a year old.
There are a variety of tests to diagnose liver shunts. These include X-rays, ultrasounds or a liver biopsy. There is also a test called a scintigraphy that measures blood flow, but this test is not widely available due to its complexity. Mainly tests of the blood and bile acids are done. Dogs with liver shunts also tend to have smaller livers than a healthy dog.
The usual treatment for liver shunts in dogs is through surgery. According to Dr. Karen Tobias of the University of Tennessee, the survival rate for canine liver shunt surgery is 95 per cent. If the dog is too ill for surgery, then adjustments in diet are done and antibiotics given until the dog is stronger. But all dogs with liver shunts will eventually need surgery or they will die.