The liver is responsible for several processes in a dog's body. It creates bile to aid digestion and helps rid the body of waste. The liver also helps a dog metabolize fat, protein, carbohydrates, vitamins, and minerals. Additionally, the liver filters out the toxins and waste found in foods and medications.
A dog with liver disease may have trouble performing some of these biological processes, which can lead to a really sick pet. However, some liver problems are more serious than others. Learning how to spot liver issues before they become a full-blown disease can prevent liver damage and get a sick dog back to full health.
What Is Liver Disease?
Liver disease refers to any abnormality in the liver that prevents it from functioning normally. There are several different types of liver diseases. Bile duct obstruction occurs when the tubes that carry bile from the liver to the gallbladder become blocked. A portosystemic shunt (also called a liver shunt) happens when blood from the stomach, intestines, pancreas, and spleen bypass the liver, preventing the blood from being properly detoxified. Autoimmune disease can cause scarring of the liver. Liver tumors, most common in older dogs, can be cancerous or they can be benign but still affect your pet by pressing on the surrounding liver or other organs.
Symptoms of Liver Disease in Dogs
Many types of liver problems can appear in a dog, causing a multitude of symptoms specific to the type. Often there are no symptoms until the disease is very progressed which is why regular exams and blood work are important, especially in older animals. Jaundice—a yellowing of the eyes, tongue, skin, or mucous membranes—is a tell-tale sign that something is off with your dog's liver. A liver-sick dog may also present with:
Of course, any sign of sickness may be caused by a problem in the body that is unrelated to the liver. A visit to the veterinarian will deduce the issue.
Causes of Liver Disease
Liver disease has many different causes, depending on the type. Each type is unique to a particular form of the illness. Acute liver disease can develop after exposure to a toxic substance or poison, or from exposure to excessive heat (never leave your pet in a hot car!). Some toxins can even cause different organs to fail, leading to secondary liver damage. Bile duct obstruction presents from generalized inflammation, an infection, a tumor, gallstones, or a build-up of thickened bile in the gallbladder called a mucocele. A portosystemic shunt may be present at birth or develop due to another liver problem. Chronic active hepatitis can be caused by an overactive immune system, infection, toxins, a build-up of copper in the liver (usually genetic), or by other damage that the liver could not completely recover from.
Viral, bacterial, fungal, or parasitic infections can all cause chronic liver problems. Leptospirosis, for instance, is a bacteria found in the urine of rodents and wildlife. This bacteria, when contracted by an unvaccinated dog, can cause major liver damage.
If liver disease is suspected, a vet will order lab work to evaluate organ function. Elevated liver enzymes found in the blood, like alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP), can indicate a problem. Additionally, the blood levels of bilirubin, a substance found in bile, and albumin, a protein made by the liver, provide information about overall liver health. Blood sugar levels, cholesterol, and levels of urea nitrogen—a byproduct of protein metabolism—can also give information on whether the level of liver disease constitutes liver failure. A complete blood count may indicate the presence of an infection or inflammation. Abdominal imaging, like radiographs (X-rays) or an ultrasound, may reveal scar tissue and tumors in or around the liver region. A liver biopsy may be recommended to check for the presence of bacteria, cancer cells, and more and is often the only way to get a definitive diagnosis for the cause of the liver disease.
The treatment options for acute liver disease depend on the type of disease and the degree of damage done to the liver. Fluids and electrolytes, and restricted activity are the recommended protocol for pets who have been acting sick. Medications and liver supplements are often used as well. Bile duct obstruction can sometimes be remedied with medications like ursodiol. However, for full duct obstruction, surgery is often necessary. Surgery has a high success rate for liver shunts and can be a cure for most dogs, however not all shunts can be repaired surgically and these cases will need lifelong medical management with diet and medication. Antibiotics and antiviral medications can be given in the presence of infection. Yet, chronic active hepatitis—not reversible or curable—is often managed with medications and a restricted diet. Treatment for liver tumors or cancer will depend on test results and may involve surgery, chemotherapy, and the administration of medications.
Medications and supplements, like Denamarin, can help many dogs with liver disease or damage live for years with minimal symptoms. In some cases, dietary 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.
How to Prevent Liver Disease
While keeping your dog healthy involves routine wellness exams, there are other ways to assure the health of its liver. Refrain from feeding your dog fatty foods as this may cause pancreatitis, which can secondarily affect the liver. Make sure your pet is fully vaccinated to prevent infectious causes of liver disease such as canine adenovirus and leptospirosis.
Keep all toxic substances—like antifreeze and paint solvents—locked up and out of your dog's reach.