Mar Vista Animal Medical Center

3850 Grand View Blvd.
Los Angeles, CA 90066

(310)391-6741

marvistavet.com

BILIARY MUCOCOELE

 

BILIARY MUCOCOELE: A SURGICAL LIVER DISEASE OF DOGS

It all starts with a sick, usually middle-aged or older dog. He is listless, not eating, maybe having vomiting and/or diarrhea, fever. These are symptoms that could mean any number of things but usually when he reaches the veterinarian’s examination table he has jaundice (yellow pigmentation visible in the whites of his eyes and possibly on his skin and gums). Hospitalization is recommended to rehydrate him and provide supportive care and blood tests point to a liver problem. Medications are administered to minimize the liver’s workload but soon ultrasound is being discussed to image the liver and costs may be rising quickly.

In a survey of dogs with hepatobiliary mucocoeles, the following symptoms were observed:

Vomiting – 77%
Lethargy – 73%
Appetite loss – 71%
Jaundice – 47%
Abdominal pain – 44%
Diarrhea – 29%
Fever – 22%

The alphabet soup of blood tests can be confusing and it can be tempting to wait a few days and see how medical support works out before imaging. While this may be a fair choice depending on the patient, there is an important reason to image the liver quickly and this reason is the possibility that surgery is needed urgently.

If the patient has a surgical disease,
he/she will not get better until surgery is performed.
Further, it is possible that a surgical emergency is afoot
(not only will surgery be needed but it will be needed immediately).

The sooner the surgical patient is identified, the better the chance of survival.

 

WHY DO WE NEED ULTRASOUND IF WE ALREADY KNOW THE PROBLEM IS LIVER DISEASE?

Dr. Jon Perlis of DVMSound at our hospital performing ultrasound exam.

(original graphic by marvistavet.com)

While blood testing can point to the liver, the fact is that there are numerous diseases that can affect the liver. The liver can have an infection or cancer or scarring (cirrhosis) or any number of conditions and the more specific our diagnosis gets, the more specific treatment can be.

Ultrasound represents a non-invasive way to evaluate the internal texture of the liver and gall bladder. By looking at the liver’s texture it is possible to see a tumor and determine if removing it is possible or if it has invaded too far. Ultrasound can evaluate scarring and abscessation. Through ultrasound it is possible to guide a biopsy needle to an exact area to sample tissue should this be deemed necessary.

Ultrasound evaluates the gall bladder and bile ducts. One of the more important diseases to rule out promptly is the biliary mucocoele because it commonly represents a surgical emergency. If one waits a few days to see how the patient responds to general liver support, it may be too late.

 

WHAT ARE THE GALL BLADDER AND BILIARY SYSTEM?

 

(original graphic by marvistavet.com)

The liver serves as a toxic waste processing center for the body. It filters bacterial products (as well as nutrients) entering the body from the gastrointestinal tract and it removes toxic waste products from the bloodstream. This material, that the body would like to get rid of, is bound to special biochemicals call bile acids. The solution of bile acids, water, mucus, pigments, and cholesterol forms the greenish yellow fluid we call bile.

Bile is made in the liver, collected into small ducts called bile ductules and bile ducts and moved into the greenish round organ called the gall bladder for storage. During food digestion, hormones cause the gall bladder to contract and squirt bile through the large common bile duct and into the intestine. The bile assists with digestion and carries toxins out of the body so they may be eliminated in feces. The gall bladder and its ducts represent the biliary system.

IF THE BILIARY TRACT BECOMES OBSTRUCTED,
THE PATIENT BECOMES RAPIDLY JAUNDICED, PAINFUL, AND SICK.

 

WHAT IS A BILIARY MUCOCOELE?

 

The gall bladder containing a mucocoele appears similar in texture pattern to the cut surface of a kiwi fruit.
(Photo Credit: DVMSound)

 

(original graphic by marvistavet.com)

We mentioned that one of the components of bile is mucus. In fact, normal bile is probably less than 3% mucus but when a mucocoele develops, the bile becomes mostly mucus. Normal bile is very liquid but mucocele bile is thick and goopy and will not flow easily through the common bile duct. The gall bladder distends and if it actually ruptures, it is likely the patient will likely die.

The gall bladder with a mucocoele develops an appearance on ultrasound described as resembling the cut surface of a kiwi fruit. When this is seen on ultrasound in a jaundiced sick patient, surgery to remove the diseased gall bladder should be performed as soon as possible.

 

WHY DOES THIS HAPPEN?

Mucocoele development starts with the glands that normally supply the gall bladder with mucus become overgrown and over active. There seems to be an association with this phenomenon diseases that involve increased blood cholesterol levels. Cushing’s disease, for example, represents an adrenal hormone excess and increased cholesterol is common in Cushing's disease patients. Cushing's disease patients have an incidence of biliary mucocoele development that is 29 times the incidence of patients without Cushing's disease. There also seems to be an association with mucocoele development and hypothyroidism, another hormone imbalance with an increased blood cholesterol level. Mucocoele development has been linked to pancreatitis (inflammation of the pancreas) as well.

 

(original graphic by marvistavet.com)

Having Cushing’s Syndrome increases a dog’s risk of developing a biliary mucocoele by 29 times.

Oddly, the biliary mucocoele, which is now a fairly common cause of canine liver disease, was only rarely seen before the 1990’s. No one knows why this might be so.

The Shetland sheepdog, cocker spaniel, miniature schnauzer and dachshund seem predisposed to developing biliary mucocoeles. 

Shetland Sheepdog

(photocredit: MorgueFile.com)

Cocker Spaniel

(photocredit: MorgueFile.com)

Miniature Schnauzer

(Photocredit: PublicDomainPictures.net)

Dachshund

(photocredit: MorgueFile.com)

  

REMOVING THE GALL BLADDER (CHOLECYSTECTOMY)

Removing a dog’s gall bladder is a serious surgery generally requiring referral to a surgical specialty practice. The goal of therapy is to remove the gall bladder before it ruptures. If it has already ruptured, tissue damaged by the rupture must be cleansed and/or removed. If the mucocoele has become infected, ruptured, and has spilled infected bile into the abdomen this is a particularly disastrous outcome but statistically survival rate is not impacted by this.

Mortality rate with mucocoele surgery is approximately 20-25%.

The gall bladder’s function is mainly one of bile storage. Without the gall bladder, bile simply dribbles into the intestine constantly rather than in controlled squirts. One might think this would be a problem but it turns out not to be. Some patients require long term medication for liver support but generally speaking, if the dog recovers from surgery prognosis is excellent and the patient can return to normal life.

 

WHAT IF SURGERY IS NOT AN OPTION?

There is no question that surgery is the best treatment choice but there is more to the story. Biliary mucocoeles can be in an incidental finding in dogs that are not sick or who are sick from something else and are having ultrasound of the belly for some other reason. In the patient that is not experiencing problems with a mucocoele, medication may be able to stave off illness.

As for skipping surgery in a dog that is sick from its mucocoele, this is a risky move but survival is possible.

It is possible to attempt treatment with general liver support medications, low fat diet, and choleretics (medications to help liquefy bile, such as ursodiol) but the problem is that the gall bladder is obstructed with a big wad of goop. This goop is unlikely to liquefy in a timely fashion if at all, no matter what we do. If medical management is attempted, it is important to regularly recheck the gall bladder by ultrasound to watch for any sign of progression that would indicate that surgery should no longer be postponed.

 Page posted: 8/12/2012
Page last updated: 2/9/2017