Gallbladder mucocele – A case of “kiwi” gallbladder
Remington, a 13 year old Pomeranian, had been in remission from lymphosarcoma for over a year. He was feeling well, but came to the hospital periodically for an abdominal ultrasound and blood tests to make sure that there was no recurrence of cancer. Unfortunately, on his visit in February of this year, his blood tests showed increased liver enzymes and an abdominal ultrasound showed an abnormality in the gallbladder called a gallbladder mucocele. Because Remington was not showing any signs of illness at that time, it was recommended that the abnormality be monitored with ultrasound. An abdominal ultrasound was repeated 3 weeks later. Unfortunately, there was no change in the gallbladder abnormality and no improvement in the blood tests, so a decision was made to remove the gallbladder. At surgery, the gallbladder was distended with gelatinous bile and the bile duct was filled with a mucous plug. The bile duct was flushed and the gallbladder was removed. Remington recovered well from surgery and will continue to have his routine periodic examinations. Remington was lucky because his gallbladder mucocele was found while he was still healthy and his long term prognosis is excellent. Unfortunately, if the gallbladder ruptures due to the mucocele, or there is concurrent infection, dogs may die before surgery can be performed. The following information describes this condition, the risk factors involved, the diagnostic tests that need to be performed and recommendations for treatment.
The gallbladder functions to store and modify bile that is produced in the liver. After a meal, the gallbladder contracts and drains bile into the intestine through the cystic and common bile ducts. In the intestine, bile aids in the absorption and digestion of fats and fat soluble vitamins, neutralizes stomach acid and prevents absorption of bacterial toxins. In addition, many toxic waste products, such as bilirubin (a product of the breakdown of red blood cells), are eliminated from the body by secretion into bile before being eliminated in the intestine.
A gallbladder mucocele is a gallbladder that is distended with an excessive amount of mucinous material. The presence of this mucinous material in the gallbladder can lead to obstruction of the bile duct preventing bile from draining into the intestine. Eventually, the gallbladder may rupture and cause peritonitis from the leakage of bile into the abdomen.
Gallbladder mucoceles have become an increasingly common diagnosis in older (average age 9-10 years) small to medium sized dogs. There is an increased incidence in certain breeds, such as the Cocker spaniel, Shetland Sheepdog and Miniature Schnauzer suggesting that there may be a genetic predisposition. Additional risk factors for mucocele formation include high blood levels of triglycerides and cholesterol, hyperadrenocorticism/Cushing’s disease (a disease where the adrenal glands produce excess steroid hormones) and hypothyroidism.
Dogs with a gallbladder mucocele often have nonspecific and vague signs such as a decreased appetite, lethargy, vomiting and diarrhea. These signs may wax and wane for weeks before a diagnosis is made. Unfortunately, dogs may not seem very sick until the gallbladder ruptures, in which case signs of abdominal pain, collapse and shock may be seen. On physical examination, dogs with a gallbladder mucocele may have yellow discoloration of the whites of their eyes or gums (jaundice), abdominal pain and fever. Blood tests often show increased liver enzyme values. Ultimately, an abdominal ultrasound is needed to make the diagnosis. The classic appearance of a mucocele on ultrasound and at surgery is that of a kiwi fruit on cross section, and for this reason many people refer to the disease as a “kiwi gallbladder.”
Any patient with a gallbladder mucocele and clinical signs of obstruction of the bile ducts should have the gallbladder removed (cholecystectomy) after the bile duct is flushed. If there is evidence of gallbladder rupture, surgery is an emergency. Prognosis for dogs that survive the hospitalization is excellent, but approximately 30% of patients having surgery may die depending on how sick they are when surgery is performed. Patients with a mucocele found incidentally, like in Remington’s case, may also be considered for elective cholecystectomy. If the gallbladder is not removed treatment includes antibiotics and choleretics (drugs that stimulate bile excretion) and careful monitoring with serial blood tests and abdominal ultrasounds. Although successful medical management has been reported, if the gallbladder is not removed, there is always a risk of potentially fatal biliary obstruction or rupture.
“Medical” pictures of a gallbladder that has been removed and contains a mucocele, a gallbladder cut in half to show how it looks kind of like a kiwi