Liver Disease in Dogs: Signs, Causes, and Treatment

Signs to watch for

Early signs are vague and look like many other illnesses.

• Poor appetite or picky eating
• Vomiting or diarrhea
• Tiredness and less interest in walks or play
• Weight loss
• Drinking and urinating more than usual
• Yellow color in the gums, the whites of the eyes, or the inside of the ears
• Dark orange urine or pale, grayish stools
• A swollen belly from fluid buildup
• Confusion, odd behavior, or seizures

The yellow color is called jaundice. It means bilirubin, a pigment made when old red blood cells are broken down, is building up in the blood. Jaundice does not always come from the liver. It can also happen when red blood cells are destroyed too quickly, as in some types of anemia, or when a bile duct is blocked.

When it is an emergency

Poisoning or a severe infection can cause sudden liver failure. See a vet the same day, or go to an emergency clinic, if your dog has any of these signs.

• Yellow gums or eyes together with weakness, vomiting, or refusal to eat
• Confusion, walking in circles, pressing the head against a wall, sudden blindness, or seizures
• Bruises, nosebleeds, blood in vomit, or black, tarry stools
• A belly that swells quickly
• Collapse
• Known or possible contact with a liver toxin, even if your dog still seems well

Brain signs, called hepatic encephalopathy, appear when toxins such as ammonia are not cleared from the blood, either because the liver is failing or because blood bypasses it. Bleeding happens because a failing liver makes fewer clotting proteins. After a possible poisoning, it is safer to call a vet right away than to wait for signs. With xylitol, for example, liver values can rise within hours, while visible signs of liver damage may take one to two days or longer to appear.

Common causes

Toxins are a common cause of sudden liver injury. Xylitol, a sweetener in some sugar-free gum, candy, and nut butters, can cause severe liver damage in dogs. Other liver toxins include sago palms, death cap mushrooms, blue-green algae in still water, moldy food that contains aflatoxins, and human pain medicines such as acetaminophen (paracetamol). A few veterinary medicines can also affect the liver in some dogs, which is one reason dogs on long-term treatment have regular blood tests.

Infections can damage the liver too. Leptospirosis is a bacterial infection picked up from the urine of infected animals, often through contaminated water or soil, and it tends to affect both the liver and the kidneys. Infectious canine hepatitis, caused by canine adenovirus type 1, is covered by a core vaccine and is most dangerous for young dogs.

Chronic hepatitis is long-term inflammation that slowly scars the liver. Often the cause is never found. Copper buildup in the liver is a common finding, and some breeds are more prone, including Bedlington Terriers, Labrador Retrievers, Doberman Pinschers, and West Highland White Terriers. Any breed or mixed breed can be affected.

Other causes include liver tumors, which are more common in older dogs, and gallbladder problems such as a mucocele, a buildup of thick bile. Some dogs are born with a portosystemic shunt, an abnormal blood vessel that lets blood bypass the liver. Hormone conditions such as Cushing's syndrome and diabetes can also cause changes in the liver.

Raised liver values on a blood test

Owners often first hear about liver trouble when a blood test shows raised ALT, ALP, GGT, or bilirubin. A raised number is a clue. On its own, it does not tell the vet what the problem is or how serious it is.

ALT leaks out of liver cells when they are injured. ALP and GGT tend to rise when bile flow is slowed. In dogs, ALP is also raised by many things outside the liver. Steroid medicines, Cushing's syndrome, some anti-seizure medicines, stress, and other illnesses can all push it up. Severe muscle injury can raise ALT. Puppies normally have a higher ALP because their bones are growing, and it usually settles into the adult range by about 15 months of age.

The reverse can also happen. A dog with advanced, long-standing liver disease may have normal or only mildly raised enzymes, because little active injury is left to measure. So vets look at the whole picture and often repeat the test after a few weeks.

How vets find the cause

The vet starts with questions about diet, medicines, and anything your dog might have eaten, then a physical exam. A bile acids test, using a fasting blood sample and one taken after a meal, shows how well the liver clears substances from the blood and can point to a shunt. Clotting tests, other blood values, and a urine test add detail. An abdominal ultrasound shows the size and texture of the liver and the gallbladder.

For many chronic liver problems, a firm diagnosis needs a liver biopsy. Small samples of liver tissue are taken under sedation or anesthesia and examined in a lab, where they can also be checked for copper and bacteria. Clotting is usually tested first.

Treatment and diet

Treatment depends on the cause. Leptospirosis is treated with antibiotics. A poisoned dog needs fast treatment to limit absorption of the toxin, plus supportive care. A shunt may need surgery, a gallbladder mucocele often means removing the gallbladder, and a tumor limited to one part of the liver can often be removed.

Very sick dogs are often hospitalized for intravenous fluids and supportive care while the liver recovers. Brain signs are managed with medicines that reduce the toxins made in the gut, belly fluid with a lower-salt diet and medicines or drainage, and bleeding with vitamin K or plasma. Long-term inflammation may be managed with medicine to reduce inflammation, antioxidants such as vitamin E, and medicine that helps bile flow. Dogs with copper buildup may need treatment to lower the copper. Your vet will check blood values regularly to see how treatment is working.

Diet is a big part of care. The aim is enough calories to keep a healthy weight, from tasty, easy-to-digest food given as several small meals a day. Dogs need good-quality protein to repair the liver, so vets usually lower protein only in specific cases, such as signs of hepatic encephalopathy or a shunt. Dogs with copper-related disease usually need a low-copper diet, and dogs with belly fluid may need less salt. A prescription liver diet is often the simplest way to meet these goals. Ask your vet before changing food or adding supplements or herbal products.

The outlook varies. Some dogs recover fully after a sudden injury because the liver regenerates. Dogs with chronic hepatitis that is found early can live for years with treatment. Belly fluid or brain signs usually point to more advanced disease.

Spread to other pets and people

Most liver disease is not contagious. Toxins, tumors, inherited problems, and chronic hepatitis do not pass between dogs. A few infections do.

Leptospirosis spreads through the urine of infected animals and can infect people too. If your dog is being treated for it, wear gloves when cleaning up urine, wash your hands often, and keep other pets away from where your dog urinates until your vet says the risk has passed. Infectious canine hepatitis spreads between dogs through urine, feces, and saliva, and dogs that recover can shed the virus in their urine for at least six months.

Prevention and newly adopted dogs

You can lower the risk of many liver problems. Keep vaccines current and ask your vet whether a leptospirosis vaccine is recommended where you live. Store sugar-free products and all medicines out of reach, and give human medicines only when your vet advises it. Keep your dog away from moldy food, garbage, sago palms, wild mushrooms, and still water with algae scum. Routine blood tests, especially for older dogs and dogs on long-term medicine, can catch changes before signs appear.

A dog that lived on the street may have eaten spoiled food or drunk contaminated water, and its early vaccine history is often unknown. At Paw Squadron, the first stops after every rescue are the vet and a bath, and every animal gets a checkup, treatment, vaccinations, and a microchip before adoption. Some liver conditions stay silent, though, and only show up on blood work.

After adoption, see your own vet in the first few weeks, bring the records you received, and ask whether baseline blood work makes sense. For dogs from southern Europe, including the Balkans, your vet may also suggest a test for leishmaniosis, a parasitic disease spread by sand flies that can affect the liver, spleen, and kidneys. More health guides are in PawPedia, and the dogs waiting for homes are on our Adoptions page.