Cholelithiasis associated with recurrent colic in a Thoroughbred mare.

This research article documents a case study of a 13-year-old Thoroughbred mare that had recurrent colic symptoms, which were later associated with cholelithiasis, a condition characterized by the presence of gallstones in the gallbladder or bile ducts.

Background and Case Presentation

• The 13-year-old mare had been retired from racing and presented with symptoms of colic. Over the course of a few months, the horse was admitted to the hospital twice, each time with signs of colic that were resolved through treatment with intravenous fluids and analgesics.
• On the third admission, the mare’s health didn’t improve despite extended treatments and she was put to sleep after 38 days of hospitalization, because of the severity of her condition and as per the owner’s request.

Clinical Observation and Diagnosis

• The mare exhibited various alarming clinical signs including fever and discoloration of the eyes (icterus), signals of potential liver damage. This, together with intermittent colic, indicated a possible obtructive biliary disease such as chololithiasis.
• The diagnosis was supported by laboratory findings demonstrating elevated levels of several enzymes and blood fibrinogen, indicative of obstruction in the bile duct.
• The study highlights that liver enzymes and bilirubin tests, though not routinely included in colic case screenings, can provide crucial insights in emergency situations.
• Following euthanasia, a necropsy revealed the presence of multiple liver stones (choleliths) obstructing the hepatopancreatic duct, some of which were as large as 3-5 cm in diameter.

Discussion and Conclusion

• Further histopathologic findings showed extensive liver damage, characteristic of cholelithiasis. These included biliary fibrosis (scarring), bile pigment plugging in the bile canaliculi (small drainages in the liver), hepatitis, and pigmentation in the hepatic lymph node with bile-laden macrophages (immune cells).
• In conclusion, the authors of the study emphasise that while diagnosing liver stones can be difficult in horses, the condition should always be kept in mind when identifying causes for recurrent colic.