Dear Pet Docs: Our cat has been diagnosed with liver disease and we do not know what to do. She has been vomiting for the past few weeks and now has stopped eating. Can you give us any advice?

A: Cats, just like people, have livers and gall bladders so they too can develop problems. Knowing your cat’s age and some history helps us determine which diseases are most likely, but I (Perry Jameson) can give you some information about diseases we commonly see.

There are several specific liver diseases unique to the cat and very different than the liver diseases observed in dogs and humans. This is due in part to specific anatomical and metabolic differences of the cat.

First how do you know your cat has liver disease? At home, the only way you would suspect liver disease is if your pet is icteric, a yellow color of the skin, eyes and mucous membranes. Bilirubin is a normal waste product from natural red blood cell death. Cat red blood cells have a limited life span; they wear out, the body removes them from circulation, saves the iron portion and gets rid of the rest, bilirubin. The liver cells remove bilirubin from the blood, put it into the gall bladder and it is eliminated in the feces. If the liver is not working well or the gall bladder is obstructed, then bilirubin levels start to increase. When they get high enough, they deposit in body tissues giving the skin, eyes and mucous membranes a yellow color.

If your cat is not icteric, the other symptoms are nonspecific and can be seen with many other disorders. These would be loss of appetite, weight loss, unkempt hair coat, vomiting and lethargy.

During a physical examination, your pet’s doctor may notice the icterus if you have not. She may or may not be able to feel changes in the liver during a physical exam.

Blood tests are the primary way liver diseases are diagnosed. Measuring bilirubin levels will allow us to determine that it is elevated. Liver cells also produce enzymes that are released at low levels all the time. If these enzymes are elevated, they tell us something is occurring to cause the liver to release more than normal.

Primary liver disease in cats generally falls into the following categories: idiopathic and secondary lipidosis, cholangitis and neoplasia. Fluid-filled hepatic cysts are also an occasional finding in some cats and rarely cause problems.

Hepatic lipidosis, or fatty liver, is where liver cells accumulate fat to the point it affects their ability to function. The cause of hepatic lipidosis is unknown and many theories have been put forward. Affected cats generally are older, obese cats that have undergone a stressful event and become anorexic. I have seen this following a move, introduction of a new pet or even following a marriage and new person moving into the home. Hepatic lipid accumulation also can result secondary to a number of other disease syndromes such as diabetes mellitus, pancreatitis, starvation or other organ dysfunction.

Treatment involves resolving another problem if present, and aggressive nutritional support. This usually requires placement of a feeding tube to provide adequate nutrition to reverse the changes. With appropriate treatment, 80 percent of cats will do well.

Cholangitis refers to an inflammatory disorder of the hepatobiliary system. In young cats, it is more commonly associated with a bacterial infection and may respond to fluid support and antibiotics.

In older cats, there may be inflammation without infection. It is speculated this may have been an immune response to a bacterial infection that resolved, but the inflammation continued. If left unchecked, the chronic inflammation can result in irreversible scarring and liver failure. In a large number of cats, inflammation may be found in the intestines (inflammatory bowel disease) and pancreas (pancreatitis), too. Treatment usually involves steroids to decrease the inflammation. Chronic therapy is usually needed and flareups are common.

Primary liver disease can be secondary to a viral infection (FIP) and toxic injury as well but these are not common.

Unfortunately, cats can develop liver cancer, with lymphoma being the most common. While we cannot cure this, we may be able to get them into remission where they feel well. They can also develop primary liver cancer or cancer of the gall bladder and bile ducts. In some instances, these can be surgically removed.

Feline liver disease might also be secondary to conditions such as inflammatory bowel disease, hyperthyroidism and cardiac disease.

It is not common, but our feline patients can also develop diseases where the gall bladder does not empty, so bilirubin backs up. These can be primary problems like inflammation, gall stones or tumors. Pancreatitis may cause icterus, too. The swollen pancreas and inflamed surrounding tissues may close off the bile duct.

After blood testing, the next diagnostic step is an ultrasound. This allows us to visually look for changes and is great at diagnosing gall bladder disease, pancreatitis and cancers that cause tumors. Unfortunately, it is not great at diagnosing inflammation or lymphoma.

For most liver disease, a sample is needed for a pathologist to assess under the microscope. The most benign way to obtain a sample is to aspirate the liver with a small needle. The pros are that this is safe and associated with little pain. The cons are that the sample is small and frequently the pathologist cannot give us a definitive answer. The best option in most cases is to get a biopsy through surgery or laparoscopy. This almost always gives the answer, but it is more invasive and requires anesthesia.

So to answer your question, the next diagnostic steps are bloodwork and an abdominal ultrasound. Based on this information, your veterinarians can then guide you as to if an aspirate or biopsy is needed or if supportive treatment is appropriate.

Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to petdocs@postandcourier.com.