Affects: Cats, Dogs
Canine gallbladder mucocele (GBM) is an emerging biliary disease in dogs described as the excessive and abnormal accumulation of thick, gelatinous mucus in the lumen, which results in an enlarged gallbladder. GBMs have been diagnosed more frequently in comparison to prior to the 2000s when it was considered rare. The mucus is usually pale yellow to dark green in appearance.
The name originates from the Greek word kele meaning tumour as a mucocele resembles a mass. Although this disease is primarily identified in dogs, cats and ferrets have also been diagnosed.
Signs And Symptoms: About 77% of dogs with a GBM display nonspecific and vague clinical signs that can last up to a week including;
loss of appetite
lethargy
vomiting
diarrhoea
Pathogenesis: The underlying pathogenesis and cause for a formation of a GBM is still yet to be identified. However, there is strong association with the rapid increase and hyperplasia of mucus-producing cells and hyper-secretion within the gallbladder epithelium. This will lead to distension which refers to the enlargement of something due to internal pressures. The pressure in this case is the thick mucus as it cannot be effectively expelled. Without proper treatment the severity increases as the thickened material can cause obstruction in the bile ducts. This results in the risk of gallbladder rupture which is life-threatening thus early diagnosis is necessary.
Additionally the composition of biliary sludge has been suggested to encourage the formation of a mucocele. Biliary sludge occurs when more water or mucin is reabsorbed and there is excessive bile salts. As this progresses more water is increased causing the contents to become more solid and severely decrease the motility of the gallbladder
It is most likely that there are multiple factors that contribute to the formation of a gallbladder mucocele.
Diagnosis: The diagnosis of gallbladder mucoceles is done by veterinarians and is dependent on an ultrasound examination. Additional procedures and diagnostics include physical examination and blood tests. Blood-work may reveal liver issues caused by obstruction of the common bile duct caused by sludge from the Gall Bladder. Serum Biochemical Profile (CHEM) of affected dogs with a GBM have shown elevated liver enzymes.
A urinalysis will provide information about the kidneys.
Complete Blood Count (CBC) as it will show the basic information about the red blood cells, white blood cells and platelets. This is important as a dog with a gallbladder mucocele which is infected will display a higher amount of white blood cells in comparison to healthy dogs.
Treatment: Medical management is one option for select cases. Asymptomatic patients without the evidence of gallbladder rupture can be managed medically with a drug treatment plan formulated by a veterinarian however their GBM will not be resolved in this case. Antibiotics are prescribed for a period of 6 to 8 weeks to the patient depending on the bacteria that is isolated in the bacterial cultures and microbiologic sampling. The bile could also reveal more than one infection present, in this case a combination of medications is often given. To promote the excretion of excessive bile, choleretic drugs can also be prescribed to manage the GBM. This is used to increase the bile flow by deliberately minimising the cholesterol content in the bile as well as diluting the secretions to allow it to exit more freely via the bile ducts. This occurs due to a naturally occurring bile acid present in the drug called Ursodiol. Hepatoprotectants are simultaneously prescribed to protect the liver as the gallbladder lives between two liver lobes, it works to protect it from bile acids. Dogs who are being medically managed must be rechecked for mucoceles after 4 to 6 weeks of being on antibiotics. If there are no signs of improvement and the symptoms are worsening surgery is necessary.
Surgical removal of the gallbladder also known as cholecystectomy is recommended at initial detection to avoid spontaneous gallbladder rupture since the rate of leakage or rupture is unpredictable this also removes the potential for a reoccurring GBM. If the patient shows clinical signs, abnormal blood work and pain the removal of the gall bladder is necessary. In case of rupture they should undergo immediate emergency surgery.
Before surgery begins preoperative tests must be conducted to look at a patient's blood count, urine analysis, serum chemistry profile and coagulation panel. This is to ensure that all results and levels are normal and do not display anything that isn't expected. This is necessary to commence surgery. However this would have been completed during the diagnosing process unless immediate surgery is necessary. All patients are also given appropriate intravenous fluids and electrolytes. These steps are necessary to reduce the risks of anaesthesia because most patients are older aged dogs.
During surgical procedures the whole abdominal cavity is checked in case of any concurrent and or occult problems. The bile ducts will be commonly be expressed to perform biopsies of the liver as well as the collection of bile and liver samples for further diagnosis. If the patients gallbladder has ruptured the cavity will be extensively flushed and the abdominal drained.