Biliary mucocoele in Border Terrier – a case study from our Specialists

Cases of symptomatic biliary mucocoeles are a true emergency and while mortality rates have improved significantly in recent years estimated mortality remains at 30%.

Our Internal Medicine team have written up details of a recent case of biliary mucocoele they found in a 10-year-old Border Terrier.

Presenting complaint:
5 days of progressive lethargy and hyporexia. He bloods run which had shown an hyperbilirubinaemia at 85µmol/l. He had received supportive care with fluid therapy, antiemetics, prokinetics, analgesia and antibiotics and had shown some improvement in demeanour but unfortunately bilirubin had increased further to 135µmol/l.

Diagnostic testing:
Abdominal ultrasound – this showed a distended gall bladder with organised stellate sediment filling the lumen. Free abdominal fluid was present and there was a local peritonitis surrounding the gall bladder. Otherwise within the abdomen there was some mild focal inflammation associated with the right limb of the pancreas and some diffuse hepatic change.

Diagnosis and treatment:
A diagnosis of biliary mucocoele was made. Coagulation parameters were normal and emergency surgery was recommended. At surgery the gall bladder was found to be ruptured and the diagnosis was confirmed grossly. Cholecystectomy was performed. The dog recovered well from surgery and made an excellent post operative recovery.

Biliary mucocoeles are a recent phenomenon of the last 30 years with very few cases recorded prior to this time despite being a conspicuous gross pathology finding that would have been visible at post-mortem. Many causes have been postulated including environmental (eg flea treatments), genetic and hormonal conditions. We do know that presence of an endocrinopathy (Cushings or hypothyroidism) and breed (particularly Border Terrier and Shetland Sheepdog) are associated with significantly increased risk of a biliary mucocoele.

Normal bile is formed from mucous, cholesterol and bile salts. With biliary mucocoele the normally liquid mucus molecules are altered to produce cross-linking gelatinous bile that ultimately progresses to the point of a solid structure, often likened in appearance and consistency to a kiwi fruit. This can exist asymptomatically until it grows to a critical point where it obstructs outflow and/or causes pressure necrosis of the gall bladder wall when a crisis ensues.

Symptomatic biliary mucocoeles are a true emergency and while mortality rates have improved significantly in recent years estimated mortality remains at 30% with surgical treatment. Medical management with ursodeoxycholic acid (destolit) can be attempted but should only be considered in asymptomatic patients with normal bilirubin and close monitoring is essential.