Gallstones are solid formations of bile and other compounds that coalesce in or near the gallbladder.
• Gallstones occur when the chemical makeup of bile is altered, or when the movement of bile is disrupted
• In many cases, gallstones are asymptomatic and require no treatment
• In cases where gallstones block the bile duct partially or temporarily, symptoms include vomiting, diarrhea, poor appetite and yellow gums
• Diagnostic tools include physical exam, bloodwork, X-rays and ultrasound
• Surgery is necessary to remove the stones and in some cases the gallbladder itself
• Additional treatment includes medication to increase bile flow, antibiotics, and dietary changes
• Most cases have a good prognosis with appropriate management
Gallstones occur when there is a disruption to the gallbladder. The gallbladder sits on the liver and collects bile to secrete into the intestines. Bile aids in digestion, especially of fats, and the absorption of vitamins and nutrients. Gallstones can occur in the gallbladder itself (choleliths) or in the common bile duct (choledocholiths).
In mild cases where the gallstones do not block the bile duct, there are usually no symptoms. It is possible for gallstones to remain in the gallbladder indefinitely without causing an obstruction. Sometimes, gallstones leave the gallbladder and travel through the biliary tract without complication. In some of these cases, symptoms include intermittent pain that resolves quickly.
In cases where a blocked biliary duct is severe and long-term, the bile can accumulate in the gallbladder causing it to swell. If sufficient bile accumulates, the gallbladder can rupture, spilling bile into the abdomen. A ruptured gallbladder is a medical emergency requiring urgent veterinary attention. Symptoms of a ruptured gallbladder include:
Gallstones are uncommon in dogs, but are most common in middle-aged and older female dogs. Smaller breeds and dogs with other underlying endocrine diseases such as diabetes mellitus, hyperadrenocorticism, or adrenal gland disorders are more susceptible to gallstones.
Gallstones that cause bile duct obstructions are an emergency. Dogs showing symptoms such as abdominal pain, vomiting, diarrhea, or sudden weakness require immediate veterinary attention.
The relationship between gallstones and the conditions that often accompany them is complex. It is not always clear which caused which. There are many factors that predispose to the development of gallstones, including:
• Altered chemical composition of bile from an underlying condition
• Disruptions to the normal movement of bile, such as from endocrine diseases like hypothyroidism and diabetes
• Inflammation or infection of the biliary system, including cholangitis and cholecystitis
• Poor diet
• Tumors affecting the bile duct or liver
It is difficult to determine if these changes in system function create the conditions for gallstones or gallstones create the conditions for these alterations.
Many cases of gallstones do not show symptoms. Cases that do show symptoms are often subtle and do not directly indicate a gallbladder problem. When present, symptoms include:
• Abdominal pain after eating, including unusual posture to try and relieve pain
In the case of asymptomatic gallstones, their discovery is often the result of investigation into unrelated issues. The veterinarian discovers the presence of gallstones while performing an ultrasound or X-ray. In these cases, no treatment is necessary and periodic monitoring of the gallbladder and surrounding structures is sufficient to mitigate the risk of complications. In cases where gallstones cause mild to moderate symptoms, veterinary attention is required. Diagnostic tools include:
• Physical examination
• Diagnostic imaging, such as X-rays and ultrasound
• Blood work
• Surgery to remove the gallstones or the gallbladder itself
• Medications to increase bile flow such as ursodiol
• Antibiotics in the case of infection
• IV fluids
• Pain relievers
• Anti-nausea medication
In cases where gallstones cause the gallbladder to rupture, emergency veterinary attention is required. Treatments include:
• Surgery to remove the gallbladder and evacuate bile from the abdomen
• Hospitalization with intensive care
Any time gallstones are identified, changes to the diet and the addition of dietary supplements are recommended. Typically, low-fat diets and supplementation of vitamin E are suggested for gallstone patients.
The prognosis for dogs that are asymptomatic or experience mild to moderate symptoms is good. Dogs who have had their gallbladder removed can live healthy lives, especially in cases where a low fat diet is adopted. Once the gallbladder is removed, the liver delivers the bile to the intestine directly.
For dogs where the gallbladder has ruptured, prognosis depends on how quickly the surgery is performed and how significant the complications are. Dogs who experience significant bile leakage into the abdomen require long term hospitalization and have high rates of mortality.
Preventative measures have not yet been proven, however dogs with balanced diets may have a lower incidence of gallstones. Weight management strategies are useful to prevent or mitigate endocrine disorders which are associated with gallstones.
Gallstones are one of the most common abnormalities affecting the gallbladder. Asymptomatic gallstones are common. Cases where gallstones block the biliary duct partially or temporarily are less common. Blockages that cause a rupture of the gallbladder are rare.
In asymptomatic cases, no treatment is required.
In mild to moderate cases treatment may include,
• Surgery • Ursodiol • Antibiotics • IV fluids • Pain relievers • Anti-nausea meds
In severe cases treatment includes
• Emergency surgery • Hospitalization • Intensive care
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