Ingesta-associated choledocholithiasis in horses: 2 cases and literature review.

The research article discusses a rare disease in horses known as “ingesta-associated choledocholithiasis”, providing details on two observed cases and comparing them to previous ones. This disease, indicated by the formation of a stone-like object in the bile ducts due to ingestion of foreign materials, can lead to severe symptoms in horses, often with poor prognosis.

Research Cases Details

• Case 1: This involved a 4-year-old Thoroughbred mare presenting with colic symptoms. Upon evaluating, the veterinarians found a 5-cm choledocholith (bile duct stone) enveloping a piece of hay. The horse demonstrated elevated biomarkers for liver cell damage and bile duct obstruction, and suffered from neutrophilic cholangiohepatitis, an inflammation of the liver and bile ducts, and bridging fibrosis, a form of advanced liver scarring.
• Case 2: This case involved an 18-year-old American Paint Horse mare also showing colic signs, along with long-term weight loss and abnormal mental behavior. The horse had an irregularly formed choledocholith containing fragments of hay, a wooden stick, and twigs. Like the first case, this horse also had heightened biochemical markers of hepatocellular injury and cholestasis, and was found to have extensive hepatocellular necrosis, a form of liver damage, with mild neutrophilic cholangiohepatitis and bridging fibrosis.

Microbiological Findings and Comparisons

Bacterial cultures of both cases indicated the presence of certain bacterial species known to cause infections in the bile duct. Furthermore, both cases were compared with two other cases outlined in literature previously. The resultant similarities included:

• Increased activity of cholestatic enzymes and high bilirubin levels, indicating a bile flow obstruction from the liver.
• Portal inflammation and bridging fibrosis, suggesting severe liver tissue damage.
• Colic symptoms, fever, leukocytosis with neutrophilia, or the increase in white blood cells especially neutrophils, and elevated hepatocellular enzyme activity, observed in three out of four cases.
• Foreign material found in all instances was of plant origin, suggesting ingestion of these materials led to the formation of bile duct stones.

Conclusion

The researchers suggest that ingesta-associated choledocholithiasis should be recognized among the potential causes of colic, fever, and heightened cholestatic biomarkers in horses, despite its rarity. The condition carries with it a notable risk of severe morbidity and mortality due to serious damage to the liver and bile ducts. The foreign plant material ingestion seems to be a key factor in stone formation, thus, monitoring and managing the horse’s diet can play a crucial role in the prevention of this disease.