Biliary Disorders in Horses.

Overview

• This review article discusses biliary disorders in adult horses, particularly focusing on cholangiohepatitis.
• It covers the presentation, diagnosis, and treatment of this condition, and addresses other less common causes of biliary disease in horses.

Cholangiohepatitis in Horses

• Cholangiohepatitis is inflammation of the bile ducts and liver (hepatic parenchyma) in horses.
• The disease often involves biliary obstruction within the liver (intrahepatic) or outside the liver (extrahepatic).
• This obstruction is commonly caused by the presence of thickened, “sludgy” bile or by actual stones known as choleliths.
• Unlike in humans where bile stones are often cholesterol-based, in horses, these calculi typically consist of calcium bilirubinate.
• The obstructive process leads to inflammation and can cause impaired liver function.

Clinical Features and Diagnosis

• Horses with cholangiohepatitis may show signs related to liver dysfunction and biliary obstruction.
• Presentation may include intermittent or persistent liver-related symptoms, as the disease can become recurrent and chronic.
• Diagnostic evaluation typically involves clinical examination, blood work to assess liver enzymes and function, and imaging modalities such as ultrasound to identify bile duct abnormalities or stones.
• Further diagnostic tests might include bile sampling and possibly biopsy to confirm inflammation and the presence of infection.

Treatment and Management

• Treatment aims to relieve obstruction and control infection and inflammation.
• Medical management may include antimicrobial therapy targeting likely bacterial pathogens and supportive care to improve liver function.
• In some cases, procedures to remove biliary stones or relieve obstruction may be necessary, depending on availability and clinical circumstances.
• Because the condition often recurs, long-term management strategies are important.
• Close monitoring and potential repeated treatments may be required to manage chronic cholangiohepatitis effectively.

Other Causes of Biliary Disease in Horses

• Other less common causes of biliary disorders include:
• Foreign body obstruction: Rare instances where a physical object causes blockage in the bile ducts.
• Neoplasia: Tumors affecting the biliary tract that may obstruct bile flow.
• Liver fluke infestation: In certain geographic areas, parasitic flukes infect the liver and biliary system leading to disease.
• These causes are less frequent but are important differentials to consider in horses presenting with biliary signs.

Summary

• Cholangiohepatitis is the primary biliary disorder in adult horses discussed, characterized by inflammation often associated with biliary obstruction.
• The disease may be chronic and recurrent, emphasizing the need for ongoing management.
• Recognition of the unique composition of equine biliary stones and diligent diagnostic efforts are critical for effective treatment.
• Awareness of rarer biliary diseases ensures comprehensive evaluation of affected horses.