Liver Disease in Dogs

Sick dog
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Can dogs get liver disease? How will you know if your dog has a liver problem? These are questions that may cause many dog owners to worry. Liver disease is somewhat common in dogs. In fact, there are many types of liver problems that can affect dogs, some more serious than others.

You can help keep your dog healthy by taking him to the veterinarian for routine wellness exams, as well as by learning all about the types, signs, and treatments of liver disease in dogs.

The Function of the Liver

The liver is responsible for several processes in the body. It creates bile to aid in digestion. The liver helps the body metabolize what has been ingested. This includes fats, proteins, carbohydrates, vitamins, and minerals. The liver also filters out toxins and waste found in foods and medications. The bile helps the body get rid of what is not needed by carrying it out the body in the feces. Excess bile is then transported to the gallbladder via the bile ducts.

The liver stores and excretes essential minerals, proteins, enzymes, and chemicals essential to body function. It plays an important role in blood clotting functions and the immune system. It is also a highly regenerative organ, which means it can often recover from damage. Some damage to the liver is extensive enough to cause illness.

Signs of Liver Disease in Dogs

There are many different types of liver problems. Many cause similar symptoms, but others result in vastly different signs. The following are some of the more common signs of liver disease in dogs. 

  • Lethargy
  • Vomiting
  • Loss of appetite
  • Diarrhea
  • Jaundice (yellowing of eyes, tongue, and/or mucous membranes)
  • Abdominal pain
  • Distended abdominal (due to fluid and/or enlarged liver) 
  • Fever
  • Unsteady gait
  • Confusion
  • Seizures (in the case of a portosystemic shunt)

Of course, these signs may be caused by another problem in the body that is unrelated to the liver. If your dog is showing signs of liver disease or any other signs of illness, it is crucial that you bring him to your veterinarian for care. 

What to Expect at the Vet

Your veterinarian will begin by asking questions about your dog's recent and past medical history followed by a thorough physical examination. Based on the exam findings, your vet will recommend the next steps.

It is highly likely that your vet will recommend lab work to evaluate your dog's health. A blood chemistry will tell your vet a lot about organ function. Certain enzymes, when elevated in the blood, may indicate a problem with the liver. These enzymes include alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP). In addition, the blood levels of bilirubin (a substance found in bile) and albumin (a protein made by the liver) provide information about the health of the liver.

A complete blood count measures the cells found in your dog's blood and may indicate the presence of infection and/or inflammation. A urinalysis will look at the substances excreted in the urine. Bilirubin and/or certain crystals in the urine may indicate liver problems.

Next, your vet may recommend diagnostic imaging, like radiographs (x-rays) or an ultrasound. These tests allow your vet to look at the liver as well as the surrounding organs and structures. Abdominal imaging may reveal inflammation, scarring, and even tumors. 

In some cases, your vet may recommend a liver biopsy to get a sample of your dog's liver. You may be referred to a veterinary specialist for this procedure if your primary vet cannot do it in-house. The liver tissue will be sent to a lab where a pathologist can analyze it. Histopathology may reveal the presence of bacteria, cancer cells, and more.  

Types of Liver Disease in Dogs

Since there are several different types of liver disease, there are a variety of ways to treat liver disease, each unique to a particular form of the illness.

The term acute liver disease (or acute liver failure) is used to describe an issue that has come on suddenly and majorly affects the liver's ability to function. In some cases, part of the liver become necrotic (die). Because the liver is a highly regenerative organ, there are some cases when a dog can recover from acute liver disease.

Toxin exposure is a common cause of acute liver failure. Many substances can poison dogs. Some directly impact the liver function while others cause different organs to fail, leading to secondary liver damage. Treatment options depend on the type of toxin and the degree of damage done to the liver. Xylitol, an artificial sweetener, is known to cause liver damage (and other problems) if ingested by dogs.

Bile duct obstruction occurs when the tubes that carry bile from the liver to the gallbladder become blocked. This may be caused by inflammation, infection, a tumor, a biliary mucocele or even a disorder of the muscles that control the organs in the abdomen. While some medications such as ursodiol can help with bile duct issues, surgery is often necessary to clear a bile duct obstruction.

Portosystemic shunts, also called liver shunts, occur when the blood from the stomach, intestines, pancreas, and spleen bypasses the liver, preventing toxins from being filtered out. These toxins build up in the body, leading to a variety of signs of illness, including seizures. A liver shunt may be congenital (present at birth) or acquired (developed due to another liver problem). Medication can help control the symptoms in some cases. However, surgery is more often recommended in dogs healthy enough to undergo it. Fortunately, surgery has a high success rate and can be a cure for most dogs.

Infections of the liver can also cause acute liver disease or even lead to chronic liver problems. These infections may be viral, bacterial, fungal, or parasitic. Leptospirosis is a bacteria sometimes found in the urine of rodents and wildlife. If ingested by a dog, it can cause major liver damage. It can also be contracted by humans who come into contact with the urine of an infected dog. Fortunately, there is a canine vaccine that can prevent leptospirosis in dogs.

Liver tumors and cancer can occur in dogs at any age, but they are most common in older dogs. Not all tumors are cancerous. Not all types of cancer will manifest as a tumor. It is important to follow your vet's advice for advanced imaging and diagnostics in order to determine if your dog has a liver tumor or cancer affecting the liver. If a tumor or cancer is suspected, your vet will probably recommend a liver biopsy. Treatment will depend on the results and may involve surgery, chemotherapy, and/or other medications.

Chronic active hepatitis is a term used to describe inflammation of the liver that continues long-term. It may be caused by an infection, toxin, or other damage that the liver could not completely recover from. There may be a breed or genetic disposition, or the disease may have an unknown cause. Chronic active hepatitis is generally not reversible or curable, but it can often be managed.

Medications and supplements (like Denamarin) can help many dogs can live for years with minimal symptoms. In some case, diet changes are also necessary. The response to treatment depends on the individual dog, but compliance from the owner is a major component to success. Be sure to adhere to your vet's recommendations for medications, diet, and follow-up testing and exams.