Cats and dogs don’t suffer from the same liver disorders. Here’s the top 3 most common liver diseases in our pets.
Liver Disease in Dogs
The most common type of liver disease in dogs is inflammatory. Hepatitis can be caused by infections, whether bacterial—such as leptospirosis—or viral, like Rubarth’s hepatitis, caused by a virus called canine adenovirus type 1. Ingesting a toxin or unsuitable food, or long-term use of certain medications—such as phenobarbital, which is used in managing epilepsy—can also lead to hepatitis.
When inflammation affects the hepatic tissue, fibrosis—a form of scar tissue—often sets in. Certain breeds, such as the Bedlington Terrier, Doberman, Labrador, Poodle, or Cocker Spaniel, appear predisposed, but all dogs can be affected. These lesions prevent the liver from functioning properly, a condition known as chronic active hepatitis.
Portosystemic shunts are the second leading cause of liver disease in dogs. In most cases, this is a congenital condition, meaning it is present from birth. In a healthy dog, veins from the digestive organs merge to form the portal vein. Carrying nutrients, the blood transported by this vein then passes through the liver via a network of small veins. The blood "cleansed" by the liver then flows into the hepatic vein, which joins the vena cava before reaching the heart and general circulation. In the case of a portosystemic shunt, blood from the portal vein bypasses the liver and directly enters the general circulation—the vena cava. This shunt can be intrahepatic or extrahepatic. As a result, blood from the digestive tract is no longer filtered by the liver, and harmful substances enter the bloodstream, potentially disrupting brain function.
Liver tumors, whether benign or malignant, rank third.
What about cats?
Cats are particularly prone to hepatic lipidosis. This multifactorial disorder often occurs after a period of anorexia. The body then draws energy from fat cells—adipose cells. When the amount of fatty acids reaching the liver exceeds its export capacity, fats are stored in hepatic cells as triglycerides, which impairs the organ’s proper function. Obese cats are predisposed to this condition. The disease is serious and rarely reversible without medical intervention.
The second most common liver disease in cats is cholangitis or cholangiohepatitis. This inflammatory syndrome affects the bile ducts and liver tissue. An ascending bacterial infection may be the cause, although an immune-mediated origin is suspected in certain forms. The anatomical peculiarity of cats makes them particularly prone to what is known as "feline triaditis": the coexistence of cholangitis with inflammatory processes affecting the duodenum, pancreas, and kidneys.
Finally, just as in dogs, liver tumors are the third leading cause of liver disease in cats.
What signs should you watch for?
Liver disorder symptoms vary widely and are often nonspecific. Additionally, most liver diseases present with the same signs. Early on, you may notice a loss of appetite, fatigue (ranging from mild to severe), vomiting, and increased thirst and urination. It’s only as the disease progresses that more specific symptoms appear—such as jaundice, a yellowing of the mucous membranes caused by bilirubin buildup in the blood.
Don’t wait when your pet shows signs of declining health. Only your veterinarian can, after a clinical examination along with blood tests, imaging techniques, and/or a more in-depth study of liver cells such as biopsy and histology, diagnose the issue to provide specific recommendations and tailored treatment.
