Etiology, diagnosis and treatment of canine cholangiohepatitis

Etiology, diagnosis and treatment of canine cholangiohepatitis

The biliary system in dogs is made of ducts that collect and direct bile from the liver and the gall bladder which stores bile. Just like any other tissue in the body, the ducts, gall bladder, and the liver can become inflamed. Inflammation of the ducts and gall bladder is called cholangitis. Inflammation of the liver is called hepatitis. These conditions can occur independently or together in what is termed cholangiohepatitis. [1]

According to Richard Goldstein, DVM, an associate professor of small animal medicine at Cornell University’s College of Veterinary Medicine, there are two potential sources of inflammation. He highlights that one of the origins is likely a bacterial infection, which may start in a close vicinity of an animal's gut, such as the pancreas or small intestine, and then progress up the biliary tract. This process typically results in inflammation of neutrophilic cells, which are mobilized by the body to combat bacteria. Dr. Goldstein notes that this type of infection, known as suppurative or pus-forming, generally shows a favorable response to antibiotic therapy.

The alternative situation, which occurs more frequently, involves an immune-related process that impacts lymphocyte cells. Dr. Goldstein states that these cases, referred to as nonsuppurative, typically do not react positively to antibiotics. Therefore, the common approach is to address this form of cholangiohepatitis with immunosuppressive medications like steroids, as mentioned by Dr. Goldstein. [2]

Given the frequent connection among canine cholangitis/cholangiohepatitis syndrome (CCHS), gallbladder issues, and enteric disease, there is substantial similarity in clinical symptoms across these conditions. The decreasing order of occurrence for clinical signs encompasses lethargy and vomiting (greater than 70%), reduced appetite (approximately 65%), and diarrhea (around 30%). Physical examination observations involve fever (approximately 30%), jaundice (about 25%), lethargy (26%), detectable enlargement of the liver (10%), and occasional instances of polyuria/polydipsia (PU/PD) and abdominal fluid accumulation (ascites).

Hematological characteristics associated with canine cholangiohepatitis may involve an elevated count of neutrophils, showing either a left shift with toxic neutrophils or a degenerative left shift. Alternatively, the hematology may fall within normal ranges. In the majority of cases, dogs exhibit heightened liver enzyme levels and total bilirubin, and a subset may also present with elevated cholesterol levels during the initial assessment.

Anticipated occurrences of these irregularities encompass elevated levels of alkaline phosphatase (ALP) in 98%, ALT in 88%, AST in 79%, gamma-glutamyl transferase (GGT) in 42%, total bilirubin in approximately 64%, and cholesterol in around 56%. The expected median fold increases (with respective ranges) are as follows: ALP about 10 times (ranging from 1 to 52 times), ALT about 5 times (ranging from 1 to 36 times), AST about 2–3 times (ranging from 1 to 17 times), GGT about 2 times (ranging from 1 to 16 times), total bilirubin about 5 times (ranging from 1 to 162 times), and cholesterol about 1,3 times (ranging from 1 to 4,4 times), with values within reference ranges indicated as 1 times. Uncommon abdominal effusion typically does not manifest as ascites but rather signifies altered vascular integrity associated with sepsis, iatrogenic fluid overload, or bile peritonitis. [3]

The symptoms of canine cholangiohepatitis can vary in severity and may include:

• Vomiting
• Diarrhea
• Appetite loss
• Weight loss
• Abdominal pain
• Lethargy
• Jaundice
• Increased thirst and urination
• Fever
• Dehydration
• Pale gums [1]

Initially, veterinarian will recommend performing a general lab panel (blood and urine tests). This panel will provide an overall check of the organ systems and, in the case of cholangiohepatitis, changes in the values associated with the liver. Abnormalities in the liver values on lab work are not specific for cholangiohepatitis, as other liver conditions can cause similar changes in the values. Therefore, veterinarian will recommend imaging the liver using ultrasound.

Liver size and the appearance of the liver tissue, gall bladder, and biliary ducts will be assessed. Fluid in the abdomen (ascites) can also be detected with ultrasound.

Combining lab work and ultrasound findings may result in a suspicion for cholangiohepatitis, but liver and gall bladder biopsy and culture to check for bacterial involvement are needed for a confirmed diagnosis of this condition.

Liver biopsies and gall bladder bile collection can be obtained via ultrasound, guided needle aspiration, laparoscopy, or surgery. Ultrasound-guided needle biopsies/bile collection presents the greatest risk for leakage of bile into the abdomen, when compared to the other two biopsy methods.