Liver Shunts in Dogs: Causes, Symptoms & Treatment
There’s nothing we’d want more than our dogs to be healthy and stay with us as long as possible. Unfortunately, dogs can develop various diseases and conditions that can severely impact their longevity. One of those conditions is called a liver shunt. The liver is incredibly important, and it plays several vital roles in our dog’s body. As you can imagine, if something’s wrong with this organ, you are right to get worried. Here’s what you should know about liver shunts in dogs.
The liver, as we have already mentioned briefly, is critical. However, many owners are unaware of the liver's importance. It is responsible for several vital body functions, and you must ensure that your dog's liver is in good health (and make sure yours is healthy too). Here are some of the most important functions of the liver:
- Detoxifies the blood,
- Metabolizes energy sources
- Breaks down drugs.
- Produces proteins to aid in blood clotting
- Produces bile acids to aid in digestion
- Vitamins and glycogen are stored in it
First, some canine anatomy and physiology must be reviewed. The portal system is a network of veins that drains blood away from the digestive tract. This blood transports nutrients, hormones, and waste to the liver before continuing to the rest of the body. The liver takes what it needs to function correctly and detoxifies the blood before sending it on its way.
A shunt is defined as a passage "that allows materials to flow between two structures that are not normally connected." A portosystemic shunt is a type of abnormal blood vessel (or vessels) that connects the "portal" circulatory system that drains the digestive tract to the "systemic" circulatory system that feeds the rest of the body. By doing that, it bypasses the liver.
There are two types of liver shunts: those that form at birth (congenital shunts) and those that develop later in life (acquired shunts).
Congenital shunts are the most common, accounting for approximately 80% of cases. When symptoms appear in dogs, they are usually relatively young (less than 3 years old). Some breeds have a known genetic cause, while other causes are suspected but not confirmed.
Acquired shunts occur when blood pressure within the veins connecting the digestive tract to the liver rises, most commonly as a result of diseases that cause liver scarring (cirrhosis). When compared to dogs with congenital shunts, dogs with acquired liver shunts experience symptoms later in life.
The most common symptom of a liver shunt in dogs is stunted growth. The runt of the litter is frequently diagnosed with liver shunts, which cause problems with the nutrient breakdown from food. Because of the issues with energy regulation, these small puppies may be quieter or more reserved than their healthy littermates.
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Chronic liver shunts and severe cases can cause a dog to head press, stare at walls and doors, stumble around as if drunk, circle, and even have seizures. These frightening symptoms are usually more noticeable to a dog owner than simply having a small and quiet puppy. You might not be sure if the puppy’s character merely is like that or was it born with liver shunts. The following are the most common symptoms associated with both types of liver shunts in dogs:
- Stunted growth (congenital shunts)
- Having a poor appetite and/or eating unusual foods
- Loss of weight
- Heightened thirst and urination
- Difficulty urinating or blood in the urine as a result of bladder stone formation
- Vomiting, possibly containing blood
- Diarrhea that may or may not contain blood
- Changes in behavior such as mental dullness, vacant staring, poor vision, unsteadiness, circling, and head pressing
Unfortunately, because all dogs have livers, all dogs can develop liver shunts. Breeds at a higher risk of congenital liver shunts include:
- Australian Cattle Dogs
- Cairn Terriers
- Golden Retrievers
- Irish Wolfhounds
- Labrador Retrievers
- Miniature Schnauzers
- Old English Sheepdogs
- Yorkshire Terriers
These symptoms we mentioned earlier are not limited to liver shunts. A veterinarian will begin the diagnostic process by taking a thorough look at medical history, performing a physical examination, and performing some basic tests such as blood work and urinalysis. If they suspect a liver shunt, additional testing will be required to make a definitive diagnosis. Bile acid tests, blood ammonia levels, abdominal X-rays, abdominal ultrasound, and advanced imaging studies are possibilities. Based on the specifics of your dog's case, your veterinarian can discuss the benefits and drawbacks of each test with you.
Surgery is frequently required to correct and close the shunt. This type of surgery is usually very successful in dogs with only one extrahepatic shunt. Still, multiple shunts or intrahepatic shunts may be present in some dogs, making surgery’s success rate lower.
If surgery is not financially feasible, a dog has multiple shunts, or the shunts are intrahepatic, medications and diet may help manage the symptoms. Because dogs with liver shunts cannot metabolize protein well, special diets low in protein and medications to help a dog tolerate protein are frequently used. The source of protein and the amount consumed by a dog with a liver shunt can differ from dog to dog, so a veterinary nutritionist may be involved in developing the best treatment plan for your specific dog.
If neurological symptoms such as circling, head pressing, and seizures occur, this is usually due to protein waste that is not excreted from the body due to the liver shunt. Medications may help to alleviate these symptoms, but in extreme cases, euthanasia is chosen if symptoms cannot be managed.
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Dietary changes and medications can help about one-third of dogs with liver shunts. Dogs with liver shunts located outside of the liver and surgically corrected using ameroid constrictors, or cellophane bands have the best prognosis. Around 85 percent of dogs make a full clinical recovery several months after surgery. Dogs with shunts located within the liver, on the other hand, have a higher risk of complications. However, many do very well after surgery.
World Dog Finder team