THE PET HEALTH LIBRARY By Wendy C. Brooks, DVM, DipABVP Educational Director, VeterinaryPartner.com

When a cat’s liver fails, there are four conditions that we look to as the most common causes:

• Hepatic lipidosis (fatty liver)
• Lymphoma (a type of cancer)
• Feline infectious peritonitis
• Cholangiohepatitis

The most common of the above is hepatic lipidosis, which occurs when a cat, particularly an overweight one, goes for a long period without eating. (Clearly, any condition that causes a cat to lose his appetite could cause hepatic lipidosis as a serious complication.) The next most common cause of feline liver failure is cholangiohepatitis, which amounts to a bacterial infection and prognosis is generally fair. The other two common causes carry a much poorer outlook, so obviously it is important to distinguish them and this can only be done with some sort of tissue sampling of the liver, ideally a biopsy.

We will assume that you have already had this procedure done, that you already know your cat has cholangiohepatitis, and that you are looking for more information.

What is Cholangiohepatitis?

The word cholangiohepatitis breaks down into “chol” (bile), “angio” (vessel), hepat (liver) and “itis” (inflammation). Putting this all together means inflammation of the liver and bile ducts.

You have probably heard of bile ducts but may not really be sure what bile is all about. Bile is a greenish material the liver makes, then transports to the gall bladder via small bile ducts. The gall bladder is a small greenish sac about the size of a superball where bile is stored. When the appropriate hormonal signals are present, the gall bladder contracts and squirts bile into the small intestine via one very large duct called the common bile duct.

Bile has several functions. It emulsifies the fat in our diets so that we can absorb it into our bodies. It also serves as a medium to dump toxins that the liver has removed and processed from our bodies.  Mixed and bonded in bile salts, these cannot be reabsorbed from the intestine back into the body and are harmlessly excreted in feces.

This is a fine system but problems can occur when the bacteria that live in the small intestine venture up the bile duct and invade the liver, which is normally sterile (free of bacteria). Inflammation results and the liver can fail.

What is the Connection with Inflammatory Bowel Disease and Pancreatitis?

In one study, 80% of cats with cholangiohepatitis also had inflammatory bowel disease and 50% also had pancreatitis.

Feline anatomy is a little different from other species. In cats, the pancreatic duct, which delivers digestive enzymes to the intestine, opens into the same pore as the common bile duct. Both ducts share a doorway to the intestine. This means that if bacteria invade the doorway, both the liver and pancreas are at risk for infection.

Inflammatory bowel disease involves infiltration of the intestinal lining with cells of inflammation. Absorption of nutrients becomes altered, which in turn alters the populations of bacteria living in the intestine. An overgrowth of bacteria can occur or more aggressive species of bacteria can take over the area. It is easy to see how the bile duct can become invaded.

Treatment

A cat in liver failure will require hospitalization, fluid therapy, and some kind of nutritional support (force-feeding, syringe feeding of a liquid diet or whatever is necessary) regardless of the cause of the liver disease.

Antibiotics
Antibiotics are helpful in any liver failure case as they help reduce the intestinal bacterial populations (any noxious substances they produce are normally detoxified by the healthy liver, but a sick liver will not be so efficient). Antibiotics also clear the liver of invading bacteria, which is what cholangiohepatitis is all about. Expect the cat to require 3 to 6 months of antibiotics after recovery.

Choleretics
A choleretic is a medication that makes bile more liquid so that it can flow smoothly without sludging. Flow of bile in the proper direction helps remove not only the toxins the liver is trying to remove in bile but also helps prevent bacteria from swimming upstream towards the liver tissue. The chief choleretic prescribed for animals is ursodiol. A cat may well be on this medication for life after an episode of cholangiohepatitis.

SAMe
This nutritional medicine has gained tremendous popularity in therapy for all liver diseases and should probably not be left out here. SAMe stands for S-adenosylmethionine. It has several desirable functions but mostly it is an antioxidant, protecting the sick liver cells from the toxins they have absorbed and normally would be excreting in bile.

Silymarin
This is the active ingredient in the herbal medication commonly known as milk thistle. It has been shown to be protective to the liver in Amanita mushroom poisoning and many have extrapolated that it should be protective to the liver in other toxic scenarios. It can be prescribed for cats with cholangiohepatitis.

Immune Suppression

This may seem intuitively inappropriate for a condition that involves a bacterial infection, but some patients simply cannot get better until their immune system is suppressed. Why? For many cats, the problem started with inflammatory bowel disease: infiltration of the intestinal lining with inflammatory cells. Immune suppression is the cornerstone of therapy for this condition. Once the immune reaction is suppressed, the lining of the GI tract regains normal thickness and function, the bacterial bloom subsides, the invasion of the liver and pancreas ceases. In some cases, immune suppression is simply needed to relieve the inflammation inherent to cholangiohepatitis. Typical medications include prednisone (or prednisolone depending on how severe the liver failure is). More aggressively, chlorambucil, a chemotherapy drug, is used.

Overall, cholangiohepatitis is one of the more treatable liver conditions of cats. This does not mean that every cat will recover; some cats are quite advanced by the time they are first seen by the veterinarian. Pancreatitis can represent a lethal complication, depending on severity. Cats that survive an acute episode can expect long term medication administration and the possibility of relapse or flare-up. The owner should become familiar with inflammatory bowel disease  and pancreatitis   as well.

Date Published: 3/28/2005 11:23:00 AM
Date Reviewed/Revised: 02/25/2007