Biliary disorders in horses warrant closer attention in chronic cases: full analysis
A review in Veterinary Clinics of North America: Equine Practice is putting fresh focus on biliary disorders in horses, especially cholangiohepatitis in adults, a condition that can be difficult to recognize early and frustrating to manage once it becomes chronic. The authors, Simon F. Peek and Kimberley Sebastian, emphasize that these cases often involve some degree of biliary obstruction, whether from inspissated bile, biliary sludge, or mineralized stones, and that recurrence is common enough that clinicians should think beyond short-term stabilization. (merckvetmanual.com)
That matters because equine biliary disease sits at the intersection of internal medicine, imaging, and sometimes surgery. Horses have no gallbladder, an anatomic difference that shapes both disease presentation and biliary flow. Published case literature suggests that choledocholithiasis and related obstructive disorders can be clinically silent for a time, but they can also progress to cholangitis, cholangiohepatitis, hepatic fibrosis, and significant hepatobiliary injury. (pmc.ncbi.nlm.nih.gov)
The broader clinical picture is often nonspecific. Merck’s veterinary references describe signs including weight loss, abdominal pain, fever, depression, and jaundice, while review literature on equine clinical pathology notes that GGT is a particularly useful screening marker for hepatobiliary disease in horses. When GGT is markedly elevated relative to hepatocellular leakage enzymes such as SDH, GLDH, or AST, biliary disease, including cholangiohepatitis, should move higher on the differential list. Inflammatory markers such as fibrinogen or serum amyloid A can also support suspicion of an active inflammatory process. (merckvetmanual.com)
The source review’s focus on obstruction is consistent with other published material. Merck states that cholelithiasis in horses may cause biliary obstruction and concurrent liver disease, although some stones are incidental findings. A recent case series and literature review described extrahepatic biliary obstruction associated with ingesta-related choledocholithiasis and noted that these lesions can ultimately drive fibrosis and cholangiohepatitis. In horses, the stones are generally pigment stones rather than cholesterol stones, which is an important distinction when veterinarians are explaining pathophysiology and recurrence risk to pet parents. (merckvetmanual.com)
Direct expert reaction to this specific review was limited in publicly available sources, but the surrounding literature points to a consistent clinical message: these are not cases to underestimate. AAEP proceedings and review articles describe cholangiohepatitis and cholelithiasis as conditions that may require serial monitoring, imaging, and, in selected cases, surgery. They also reinforce that prognosis is tied to the severity of concurrent hepatic injury and fibrosis, not just the presence of stones or enzyme elevations alone. (aaep.org)
Why it matters: For equine veterinarians, the practical takeaway is that biliary disorders deserve earlier consideration in adult horses with persistent inflammatory signs, recurrent colic, unexplained icterus, or a cholestatic biochemical pattern. Workups may need to go beyond routine bloodwork to include ultrasound, bile duct assessment where possible, and liver biopsy for diagnosis and prognosis. The chronic, recurrent nature described in the review also has implications for case communication, follow-up planning, and setting expectations with pet parents, especially when medical management may be prolonged or when referral for surgical evaluation becomes necessary. (merckvetmanual.com)
What to watch: The next step for the field is likely not a single breakthrough therapy, but better recognition and stratification of cases, including which horses can be managed medically, which need intervention for obstruction, and which are at highest risk for recurrence or progression to fibrosis and liver failure. (merckvetmanual.com)