Cholecystectomy for a ruptured gall bladder mucocoele in a dog

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Gall bladder mucocele (GBM) formation has been considered a significant biliary disease in dogs over the past decade1 and is the most common cause for surgical intervention of canine extrahepatic biliary tract disease2. The consolidation of inspissated bile leads to a reduction in biliary flow, subsequent obstruction and possible rupture of the gall bladder, resulting in bile peritonitis. 

Despite the high mortality rate associated with cholecystectomy in dogs, there is still considerable ambiguity regarding its origins and a lack of consensus regarding the optimal time for surgical intervention in those with GBM1.  

This case report is of a seven-year-old, male-neutered Shetland sheepdog, who presented at emergency for vomiting, diarrhoea and inappetence after being fed a hamburger. He had a long history of gastrointestinal sensitivity but had otherwise been healthy. Examination was unremarkable apart from moderate cranial abdominal discomfort. The dog was trialled on a course of anti-emetics and analgesia, probiotics, and a bland diet.  

He was readmitted to emergency two days later for persistent anorexia, dehydration and yellow diarrhoea. Examination revealed mild pyrexia (39.5oC). Biochemistry revealed moderately elevated ALT (157 U/L), AST (57 U/L) and ALKP (1353 U/L), and complete blood count (CBC) revealed leucocytosis with neutrophilia and monocytosis. Coagulation profile was normal and serum lactate was 1.6 mmol/L.

The dog subsequently underwent abdominal ultrasonography, performed by an internal medicine specialist, which revealed a moderate amount of peritoneal effusion and a cystic structure adjacent to the duodenum measuring 3.3cm. The quadrate liver lobe was hyperechoic but the remainder of the hepatic parenchyma was normal. The mesentery in the cranial abdomen was hyperechoic and there was a strong suspicion of peritonitis, likely due to GBM rupture.

gall bladder mucocele

The dog was referred to surgery and underwent emergency exploratory laparotomy, performed by a surgery specialist. A ventral midline abdominal approach was performed with routine exploration of the abdominal cavity. The abdomen had a large volume of bile-tinged free abdominal fluid with free-floating mucoid gall bladder content. The gall bladder had ruptured and there were numerous adhesions between the gall bladder and liver lobes, confirming the diagnosis of a ruptured GBM with bile peritonitis. 

A 4-0 PDS stay suture was placed in the apex of the gall bladder and the gall bladder was dissected from the hepatic fossa to the level of the common bile duct, using a combination of electrocautery and blunt dissection. A 4-0 PDS encircling suture using a Miller’s knot was placed around the origin of the cystic duct, followed by a second 4-0 PDS encircling suture, and the gall bladder was amputated. The cystic duct was oversewn with a 4-0 PDS simple continuous suture. A biopsy of the liver was obtained using the guillotine method with a 3-0 PDS suture. The remainder of the abdominal cavity was unremarkable, apart from a diffusely mildly inflamed pancreas. 

A gastrostomy feeding tube was placed using a 12 Fr Foley catheter, with the balloon inflated with 10 mL of saline. The feeding tube was secured to the stomach with a 3-0 PDS purse-string suture and pexied to the internal abdominal wall using 4-0 PDS simple interrupted sutures. The feeding tube was also secured to the external abdominal wall using a 3-0 Dermalon fingertrap suture. 

A Jackson Pratt (JP) drain was also placed in the abdomen and exited through a stab incision through the right ventral abdominal wall. The JP drain was secured to the external abdominal wall using a 3-0 Dermalon fingertrap suture. The abdomen was copiously lavaged with warm sterile saline and the external rectus sheath was closed with a 2-0 PDS simple continuous suture. The skin was closed with a 4-0 Monolus continuous intradermal suture and skin staples. 

Samples of the gall bladder and the liver biopsy were submitted for histopathology. A swab of the gall bladder contents was submitted for microbial culture and sensitivity testing. In the interim, the dog was started on empirical antibiotic treatment using amoxycillin/clavulanic acid (Amoxiclav Juno, Juno Pharmaceuticals). Antibiotics were ceased after final culture and sensitivity results were received, which were negative. 

gall bladder mucocele

Histopathology of the gall bladder was consistent with a biliary mucocele with infarction. The cause of infarction in these lesions is unknown and is thought to potentially be associated with an ischaemic event. Histopathology of the liver biopsy was consistent with moderate chronic lymphoplasmacytic and granulocytic cholangitis with moderate periglandular fibrosis and canalicular bile stasis, likely secondary to obstructive biliary disease. 

Following surgery, the dog was transferred to the ICU department for post-operative monitoring and ongoing supportive care. A urinary catheter was passed and connected to a closed collection system to prevent urine contamination of the surgical incision. The JP drain and urinary catheter were removed two days after surgery and he was discharged home four days after surgery.

At follow-up examination a week later, the dog was bright and the surgical site was healing well. The gastrostomy feeding tube was removed. Skin staples were removed the following week with complete healing of the surgical incision.

Whilst the mortality rate associated with cholecystectomy in dogs is relatively high, studies have found no association between mortality rate and biliary rupture3. Rather, major negative prognostic factors have been reported to be elevations in post-operative serum lactate concentrations and immediate post-operative hypotension3. This was supported in this case, where blood pressure was maintained within normal ranges and lactate peaked at 1.9mmol/L post-operatively and continued to trend downward, resulting in an excellent surgical outcome.


References:

1. Rogers, E., Jaffey, J. A., Graham, A., Hostnik, E. T., Jacobs, C., Fox-Alvarez, W., Eerde, E. V., Arango, J., Williams 3rd, F., DeClue, A. E. (2019). Prevalence and impact of cholecystitis on outcome in dogs with gallbladder mucocele. Journal of Veterinary Emergency and Critical Care. doi:10.1111/vec.12910. 

2. Mayhew, P. D., Weisse, C. (2017). Chapter 95: Liver and Biliary System. Tobias, K. M., Johnston, S. A., Veterinary Surgery: Small Animal (pp. 1848-1849). Elsevier. 

3. Malek, S., Sinclair, E., Hosgood, G., Moens, N. M. M., Baily, T., & Boston, S. E. (2013). Clinical Findings and Prognostic Factors for Dogs Undergoing Cholecystectomy for Gall Bladder Mucocele. Veterinary Surgery, 42(4), 418–426. doi:10.1111/j.1532-950x.2012.01072.x


Dr Lily Pham 

gall bladder mucocele

BPharm, Grad Cert Pharm Prac Int, DVM

Surgery intern

Dr Lily Pham graduated as a Doctor of Veterinary Medicine from the University of Melbourne in 2020 and spent the first few years of her career in small animal general practice. 

She is currently undertaking a surgery internship at Animal Referral Hospital in Essendon Fields, Melbourne and hopes to continue developing her skills in this area.

Dr Tania Shaw 

gall bladder mucocele

BVSc (Hons), Grad Dip Ed, DACVS-SA

Specialist in small animal surgery

Dr Tania Shaw graduated from the University of Sydney in 2007 with first class honours, and then spent three years in general practice in Melbourne. 

She completed a small animal rotating internship at Queensland Veterinary Specialists in Brisbane in 2011, followed by a surgical internship at Melbourne Veterinary Specialist Centre in 2012, and another surgical internship at the Murdoch University Veterinary Teaching Hospital in Perth in 2013.

Dr Shaw then returned to Melbourne to complete a three-year small animal surgery residency at Melbourne Veterinary Specialist Centre. 

After completing her residency, she joined Animal Referral Hospital in Essendon Fields, Melbourne as a surgery registrar while preparing to sit her ACVS Board examinations in small animal surgery. She passed her exams in March 2020 and is now a ACVS boarded specialist surgeon, making her a recognised specialist in small animal surgery in both Australia and the US.

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