(original graphic by marvistavet.com)
We will begin this discussion assuming the cat in question has already been diagnosed with liver failure/hepatic insufficiency, based on routine blood work, manifestation of jaundice (also called "icterus"), and general symptoms of malaise, appetite loss and/or intestinal distress. Since treatment and prognosis of liver failure vary highly with the actual nature of the liver disease in question, further tests are typically needed.
Ultrasound or similar advanced imaging, looks at the textures of the liver tissue. If a tumor is present or a disease process involves part of the liver, imaging can detect the texture changes and help with the diagnosis. If the liver is affected diffusely (meaning the whole liver is involved in the disease equally), a tissue sample is going to be needed to figure out what it going on and that means either an aspirate or a biopsy.
An aspirate or needle biopsy involves withdrawing a small sample through a needle. The cells obtained this way can be examined individually. This method can detect lymphoma and lipidosis readily but cholangitis is a bit trickier because it involves the bile duct system and may not involve the actual liver tissue that the bile ducts travel through. Looking at liver cells individually may not be helpful. For a diagnosis of cholangitis, a chunk of tissue for biopsy is best so as to see the inflammation in the bile ducts. Culturing the bile fluid is also useful as infection of the gall bladder is frequently involved in the most common types of cholangitis, though obtaining the sample can be challenging without actual surgery. Let us assume for the rest of the article that we have confirmed or have strong suspicions that the cat has cholangitis/cholangiohepatitis.
WHAT IS “CHOLANGITIS?" AND IS IT DIFFERENT FROM "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. Recently, it has been determined that the term "cholangiohepatitis" should probably be replaced by the term "cholangitis" because, in cats, inflammation into the liver itself separate from the bile system is not consistently found. Still, the term "cholangiohepatitis" has been used for years and will probably continue to be used. Your veterinarian may use either or both terms interchangeably.
(original graphic by marvistavet.com)
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 and 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 bind toxins that the liver has processed so they can be expelled into the intestine and defecated away.
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?
This combination of cholangitis (particularly the acute neutrophilic form), inflammatory bowel disease, and pancreatitis is often referred to as "triaditis." Often the patient does not recover until all three conditions are addressed.
Recently the World Small Animal Veterinary Association (WSAVA) has organized a classification system for liver disease and has defined several categories of cholangitis:
The liver biopsy can generally distinguish all of these conditions.
Most cats begin to show great improvement within one week of beginning proper therapy.
In time, the acute disease described above will progress into a chronic disease which is also called "lymphocytic-plasmacytic" cholangitis. Scarring begins to complicate the disease. Affected cats tend to be older than those with acute disease and tend to show a more waxing/waning disease course over time. Treatment is similar to what is described above except that immune suppression/anti-inflammatory medication is needed to control the inflammation and minimize the scarring. Often medication is needed indefinitely or very long term.
This may seen intuitively inappropriate for a condition that involves a bacterial infection, but some patients simply cannot get better until their immune system is suppressed. Why is this? 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, or cyclosporine, an immune modulator, can be used.
This form of cholangitis represents a more extreme type of lymphocytic cholangitis where the liver is completely infiltrated with lymphocytes and scarring is present. When disease has gotten this extreme, it is has become very difficult to treat. At this point, bile ducts have actually been destroyed and the entire liver may be involved. A chemotherapy protocol using methotrexate has been proposed by Cornell university.
Page last updated: 11/8/2021