Cholangiohepatitis

Cholangiohepatitis is inflammation of the bile ducts and adjacent liver parenchyma in cats. It is one of the most common hepatobiliary diseases in cats.

Two main forms:

• Neutrophilic (acute suppurative): Ascending bacterial infection from GI tract; acute illness, fever, icterus, painful abdomen
• Lymphocytic (chronic non-suppurative): Immune-mediated; chronic waxing/waning signs; weight loss, anorexia, vomiting

Triaditis: Concurrent cholangiohepatitis + pancreatitis + IBD. Very common in cats due to shared pancreatic and bile duct anatomy (common channel). Any cat with cholangiohepatitis should be evaluated for all three.

Clinical signs: Icterus (most common), vomiting, anorexia, weight loss, lethargy, hepatomegaly, pyrexia (neutrophilic form).

Laboratory:

• CBC: Neutrophilia with left shift (neutrophilic); normal or stress leukogram (lymphocytic)
• Chemistry: ↑ ALP (cholestatic), ↑ ALT (hepatocellular), ↑ bilirubin (conjugated), ± ↓ albumin
• Coagulation: PT/aPTT may be prolonged due to vitamin K malabsorption

Imaging:

• Ultrasound: Hepatomegaly, hyperechoic liver, distended bile ducts, pericholecystic fluid
• Evaluate pancreas and GI tract for triaditis

Aspiration / Biopsy:

• FNA: Good for ruling out lymphoma; poor for distinguishing neutrophilic vs lymphocytic cholangitis
• Laparoscopic or surgical biopsy: Gold standard for definitive diagnosis and differentiation from lymphoma

Neutrophilic cholangiohepatitis:

• Antibiotics: Amoxicillin-clavulanate 13.75 mg/kg PO q12h or enrofloxacin 5 mg/kg PO q24h for 4–6 weeks
• Ursodiol: 10–15 mg/kg PO q24h (choleretic, hepatoprotective)
• SAMe + vitamin E: Hepatoprotective antioxidants
• IV fluids: If dehydrated or anorexic

Lymphocytic cholangiohepatitis:

• Prednisolone: 1–2 mg/kg PO q12h, taper to lowest effective dose
• Ursodiol: As above
• Monitor: Serial liver enzymes; biopsy if no response to rule out lymphoma

Supportive:

• Nutritional support: Highly palatable diet, appetite stimulants (mirtazapine), or feeding tube if needed
• Vitamin K if coagulopathic
• Cobalamin if concurrent IBD/pancreatitis