A Gallbladder Mucocele (GBM) or Canine Gallbladder Mucocele is an inappropriate accumulation of mucus or inspissated bile in the gallbladder lumen. It was considered a rare condition but sadly GBMs are becoming an increasingly common diagnosis, especially in older, small- to medium-sized dogs.

Predisposing factors

 

It has been found that MC usually occur in geriatric patients with a median age of 9 years. No sex predisposition has been noted. Smaller dogs (<20 kg) seem to be more commonly diagnosed.

Breeds that are over-represented include:

Cocker Spaniels, Shetland Sheepdogs, and Miniature Schnauzers. Other breeds affected include; Terriers (West Highland White, Scottish), Maltese, Shih Tzu, Pug and Bichons.

Felines can also be affected although this is less common.Cocker spaniels like our Gabby appear to be the most commonly afflicted breed with Shetland sheepdogs and miniature schnauzers also affected. We wished we had known this before.

While the exact cause of Gallbladder Mucoceles (GBMs) is unknown, histologic findings have consistently demonstrated a dysfunction and proliferation of the mucus-secreting glands in the gallbladder wall. Secreted mucus causes distension, obstruction, and in some cases, eventual rupture of the gallbladder. It is unclear whether or not cystic hyperplasia is a primary cause of mucocele formation or secondary to an underlying gallbladder dysfunction or dysmotility. Previous research suggesting an inflammatory or bacterial etiology has not been consistently supported and the etiology is complex and multifactorial.

Diagnosing a Gallbladder Mucoceles (GBMs) is best done via ultrasound imaging.

 

Initial detection of a Gallbladder Mucoceles (GBMs) on ultrasound sometimes occurs incidentally while evaluating for another disease process, but most often it is found alongside an array of non-specific clinical signs. The most common of these include vomiting, anorexia, and lethargy. On physical examination, more specific findings may include abdominal pain, icterus, fever, tachypnea, and tachycardia. A CBC in these dogs is usually unremarkable, but serum biochemistry panels may reveal elevated activities of ALP, ALT, aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT), as well as increased concentrations of blood urea nitrogen (BUN) and total bilirubin. In some cases which lack clinical signs, an unexplained increase in ALP activity may be the only finding which is why we advocate for ultrasounds and specialized blood tests.   

Surgical Treatment for Gallbladder Mucoceles (GBM)

Surgical treatment via cholecystectomy is recommended for dogs diagnosed with a Gallbladder Mucoceles (GBM). This recommendation is based on a number of factors. First, the histologic evidence of mucosal hyperplasia in t  the gallbladder itself is diseased. Also, the semisolid mass of bile-laden mucus that forms in Gallbladder Mucoceles (GBMs) seems unlikely to pass through the use of choleretics, and the risk of rupture and secondary bacterial infections puts the dog at risk until the mucocele has been removed.

Gallbladder Mucocele (GBMs) in dogs can be asymptomatic. In dogs without clinical signs, surgery can be scheduled on an elective basis. More serious cases, and particularly those with evidence of rupture, should be treated as a surgical emergency. Unfortunately, 40% of dogs are asymptomatic until it is too late and surgery is the only option.

Survival and Prognosis

Survival following surgery of this kind tends to be guarded, which reflects the compromised state of the gallbladder at the time of surgery. The perioperative mortality rate ranges from 21% to 32%. The highest level of risk is associated with the early postoperative period, and dogs that survive this period are considered to have a general good prognosis.

Medical Management of Gallbladder Mucocele in Dogs

Less is known about medical management of Gallbladder Mucocele (GBMs). Medical treatment is generally reserved for animals lacking clinical signs or for those whose owners are unable or unwilling to pursue surgery. The mainstay of medical management for a Gallbladder Mucocele (GBMs) includes ursodeoxycholic acid (10 to 15 mg/kg, PO, divided into 2 doses per day), and s-adenosylmethionine (20 mg/kg, PO, on an empty stomach). It is also recommended that these patients return once or twice a month for ultrasonographic monitoring of their Gallbladder Mucocele. If concurrent hypothyroidism is diagnosed, management with levothyroxine may help to improve gallbladder emptying. Low fat diets may also improve biliary flow, especially in patients with confirmed hypertriglyceridemia. It has also been suggested that impaired enteric bile flow increases the risk of bacterial translocation and complicating infections in these patients; therefore, bile culture or prophylactic treatment with antimicrobials may be indicated

Outcomes of Medical Management

Medical resolution of Gallbladder Mucocele (GBMs) has been documented; however, the success rate is not encouraging. In some cases, the GBM does not resolve, but remains static for long periods of time. Even in subclinical cases, GBMs have been known to transform into an acute clinical condition.

Client Education

Clients should be told about the risks associated with medical management. It is also important to educate clients to detect the signs of gallbladder rupture which always requires immediate surgical intervention.

Conclusion

In summary, Gallbladder Mucocele (GBM) in dogs presents with non-specific clinical signs, often necessitating surgical cholecystectomy for treatment. Surgical success varies, and there is a notable perioperative mortality rate. Medical management options are available for asymptomatic cases but have limited success. Regular monitoring and client education on gallbladder rupture are crucial. Early detection and appropriate treatment are key to improving outcomes for dogs with GBMs.M