LIVER SHUNT

 

What is a liver shunt?

 

A liver shunt is a condition in which a portion of the blood in the body by-passes the liver and goes directly to the heart.  Toxins. especially ammonia build up in the blood stream and the dog has seizures due to increased ammonia levels.  The liver is usually smaller than normal and will have decreased liver function.  Secondary liver infection can occur but this plays a minimal role in the liver shunt syndrome.  It is the bypassing of the blood through the liver that is the major problem.

 

The symptoms of  liver shunt can start to appear at almost any age.  Dogs with a liver shunt are usually very thin dogs that pick at food.  They not only have a poor appetite, but they can become lethargic, dizzy, and stagger.  They may try to climb out of their pen, climb higher on you and cry and throw their head far back after eating,  and they may go into convulsions.

 

Many breeders feel that it is an inherited disease and that the only way to eliminate that disease is to cull those dogs that are affected and producing this disease from their breeding program.  SO FAR, IT HAS NOT BEEN PROVEN THAT THIS IS INDEED A HEREDITARY DISEASE, but it will probably be proven with the DNA studies that are being done right now.  If a puppy has a test score that says it is free of liver shunt, it will never develop the hereditary type, but ANY YORKIE can develop an acquired liver shunt due to poor diet, high protein diet, stress and other factors.

 

Treatment

 

This disease usually goes hand in hand with a kidney disorder and it seems that a special diet can sometimes keep it under control with some dogs for a time.  Surgery sometimes works depending on where the "shunt" is and how large it is

 

Liver shunt acquired vs. Congenital

 

Acquired shunts can form with severe liver disease or other conditions that cause high blood pressure in the liver.  Shunts usually connect the portal vein, which normally carries blood from the intestines to the liver, to the caudal vena cava, which carries blood from the legs and kidneys to the heart.  if blood pressure in the portal vein gets too high - maybe from scar tissue or severe swelling in the liver - shunts will form to carry the blood somewhere else.  If there was a toxin in the food that caused severe liver swelling and scar tissue formation, then that could cause shunts to form.  However, most dogs are very sick with the liver disease before they form acquired shunts and most continue to have health problems afterwards.

 

In other words, if their liver is so damaged that they form shunts (like people with alcoholism and cirrhosis), it usually remains damaged.  Some shunts may get smaller as the liver swelling goes down.   Many veterinarians only guess that a shunt is there based on blood work changes.  We have seen several older dogs that have congenital shunts that are fine unless they get another illness; then the problem of the shunt shows up.  Once the other illness resolves, the shunt may not cause noticeable problems (at lease, the owners may not detect them).

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