Serum gamma glutamyl transferase activity in horses with right or left dorsal displacements of the large colon.
Authors: Gardner Rachel B, Nydam Daryl V, Mohammed Hussni O, Ducharme Normand G, Divers Thomas J
Journal: Journal of veterinary internal medicine
Summary
Right dorsal displacement of the large colon (RDDLC) in horses produces a distinct biochemical signature absent in left dorsal displacement (LDDLC), according to this retrospective analysis of 37 RDDLC and 48 LDDLC cases confirmed surgically or post-mortem. Nearly half the RDDLC horses (49%) displayed elevated serum gamma glutamyl transferase (GGT) activity compared with just 2% of LDDLC cases, with surgical findings demonstrating that dorsal positioning of the colon compresses the bile duct, resulting in extrahepatic bile duct obstruction. This mechanistic insight—that GGT elevation in RDDLC reflects bile duct compression rather than primary hepatic disease—carries important diagnostic value: whilst 97% of RDDLC cases achieved good long-term outcomes with none developing secondary hepatic complications, clinicians can differentiate displacement type and anticipate the prognosis more confidently when GGT elevation accompanies colic signs. For farriers and equine physiotherapists, these findings reinforce that RDDLC is surgically addressable with favourable recovery prospects, whilst the GGT marker assists your veterinary colleagues in narrowing differential diagnosis and guiding case management in the critical immediate period.
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Practical Takeaways
- •Elevated serum GGT in a colic case can help differentiate RDDLC from LDDLC, supporting clinical diagnosis and surgical planning
- •RDDLC-induced bile duct compression is reversible with successful surgical correction, as evidenced by good post-operative outcomes without hepatic complications
- •GGT measurement within 24 hours before surgery is a useful diagnostic tool to support presumptive diagnosis of right versus left dorsal displacement
Key Findings
- •49% of horses with RDDLC had elevated serum GGT activity compared to only 2% with LDDLC
- •RDDLC results in compression of the bile duct causing extrahepatic bile duct obstruction and elevated serum GGT
- •97% of horses with RDDLC were discharged with good prognosis and none subsequently developed hepatic disease
- •Serum GGT activity is significantly higher in RDDLC than LDDLC cases