Medical treatment of cholangiohepatitis and cholelithiasis in mature horses: 9 cases (1991-1998).
Authors: Peek S F, Divers T J
Journal: Equine veterinary journal
Summary
Cholangiohepatitis and cholelithiasis in horses present significant diagnostic and therapeutic challenges, yet limited guidance exists on optimal medical management strategies for these conditions. Peek and Divers evaluated nine horses diagnosed via transabdominal ultrasound and hepatic biopsy, treating them with prolonged antimicrobial therapy (median 51 days; range 17–124 days) supported by intravenous fluid therapy where clinically indicated. Seven horses recovered successfully and returned to work with minimum 12-month follow-up, though histological evidence of severe periportal and bridging fibrosis at presentation predicted treatment failure. Notably, serum gamma-glutamyl transpeptidase (GGT) paradoxically increased during early clinical improvement in surviving horses, suggesting that normalisation of biochemical markers lagged considerably behind clinical recovery—a critical observation that challenges reliance on routine liver enzymes for treatment decisions. The authors advocate continuing antimicrobial therapy until GGT normalisation rather than stopping at clinical improvement, implying that many previous failures stemmed from inadequately prolonged treatment courses, a recommendation with substantial implications for managing these challenging hepatobiliary cases in equine practice.
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Practical Takeaways
- •Prolonged antimicrobial therapy (minimum 51 days or longer) is critical for successful medical management of cholangiohepatitis in horses; treatment periods of inadequate duration may be a major cause of previous failures
- •Use transabdominal ultrasound to obtain hepatic biopsies for culture and histopathology, monitor hepatic changes, and track cholelith dissolution—do not rely on the presence or absence of discrete calculi as these are found in only about 44% of cases
- •Continue antimicrobial treatment until serum GGT values normalize rather than stopping when clinical signs improve, as biochemical indices lag behind clinical recovery; supportive IV fluid therapy is also essential in acute and deteriorating chronic cases
Key Findings
- •Seven of nine horses (78%) recovered with long-term antimicrobial therapy (median 51 days, range 17-124 days) and returned to normal use with minimum 12-month follow-up
- •Treatment failure was associated with severe periportal and bridging hepatic fibrosis on admission biopsy, with one case also presenting hyperammonaemic hepatic encephalopathy
- •All nine horses had suppurative cholangiohepatitis with dilated bile ducts on ultrasound; discrete calculi were identified in only 4 cases but all had ultrasonographic evidence of biliary obstruction
- •Serum GGT levels increased during initial clinical improvement in recovering horses and should be normalized before discontinuing antimicrobial therapy, rather than using early biochemical normalization as an endpoint