The liver has many, many jobs. One of those jobs is to make bile, which helps us digest fats in our gastrointestinal tract. Bile also exports toxins from the liver into the intestines, where they can be passed with stool. Bile is made in the liver, and then transported to the gall bladder via small bile ducts. When the gall bladder gets the message that bile is needed in the small intestines, it sends bile there via one large bile duct called the common bile duct.
Usually, this system works out just fine. But occasionally, especially in cats, problems can arise. Cholangitis is the term we use to describe inflammation of the biliary tree, or the system of vessels through which bile travels. Cholangiohepatitis occurs when both the biliary tree and the liver are inflamed.
Generally, cholangitis can be classified as either being the result of a bacterial infection or it can be immune-mediated, meaning the body’s own immune system inappropriately targets the biliary tract (and sometimes the liver). Dogs can occasionally get cholangitis, but we see it much more commonly in cats. Himalayans, Persians, and Siamese cats are all overrepresented.
Clinical signs of cholangitis are highly variable, but can include decreased appetite, fever, lethargy, and weight loss. Some cats with cholangitis sometimes seem to feel absolutely fine!
Diagnosing cholangitis can be a challenge. The results of blood tests may show problems in the liver, or they may be normal. An ultrasound may be recommended so that the liver and gall bladder, and common bile duct can be visualized, but again, the results may be normal even if cholangitis is present. In cats, other diseases may be occurring concurrently, which complicates diagnosis.
While dogs can certainly get cholangitis, our feline friends are more prone due to their anatomy. Their pancreas transports digestive enzymes through the pancreatic duct, which shares an entry into the small intestine with the gall bladder’s common bile duct. Bacteria from the intestines can find its way into these portals, causing infection in both the gall bladder and the pancreas.
Consider also that 80% of cats with cholangitis also have inflammatory bowel disease (IBD) and 50% of them have pancreatitis. When the bowels are infiltrated with inflammatory cells, the contents of the bowels can become altered, favoring bacterial overgrowth. It is easy to imagine the bacteria seeping up into the common bile duct and pancreatic duct, wreaking havoc along its way.
Treatment of cholangitis depends largely on the underlying cause. If it’s bacterial in nature, antibiotics will be necessary. If an overactive immune system is to blame, medications aimed at suppressing the immune system will be used. Cats who are very ill or who are not eating may need to be hospitalized for supportive care such as IV fluids and feeding tubes. In severe cases with bile duct obstructions, surgery may be recommended.
Of course, managing concurrent IBD or pancreatitis is a must.
The prognosis is good for cases of bacterial cholangitis, but if cholangitis is immune-mediated, the illness will be harder to manage, especially in advanced cases.
Cats are creatures of habit, and they learn to hide symptoms of disease well. Pay close attention to your cat’s eating and sleeping habits. If something is amiss, please bring it up with your veterinarian. It may turn out to be nothing to worry about, but subtle changes may also signify an underlying condition, and those are best caught early!