Gallstones in Dogs and Cats

Background

The liver makes bile to help digest food and break down fats. Connected to the liver is the gallbladder, which is a sac-like organ that stores the bile and releases it into the intestines through a bile duct. Sometimes when things go awry, gallstones form inside the gallbladder. Gallstones are also called choleliths or cholelithiasis.

Gallstone Formation and Signs

Gallstones are often made up of parts of the bile, such as cholesterol, bilirubin, bile acids, and calcium. Under the right conditions, these substances can layer together inside the bile and form a solid stone. Veterinary scientists aren’t completely sure why gallstones form. Sometimes they form because either the gallbladder isn’t functioning properly or something is wrong with the bile. Conditions that make the formation of gallstones more likely are those that prevent normal movement of bile into the intestines, such as gallbladder inflammation (also called cholecystitis), or conditions that increase the number of different ingredients of bile, such as increased calcium, cholesterol, or triglycerides.

In some cases, gallstones don’t cause the pet any problems, and no clinical signs or issues are noticed; however, gallstones can sometimes lead to cholecystitis and/or cholangitis , which are painful inflammatory conditions of the gallbladder and its ducts. Gastrointestinal signs, such as vomiting or throwing up, diarrhea or loose stool, poor appetite, and sometimes a yellow tinge to the skin and eyes (jaundice) may be seen.

Should gallstones block the bile duct, bile may overfill the gallbladder, causing it to eventually burst (rupture) like a water balloon, which is a life-threatening, very painful emergency. If this happens, dogs and cats may become weak or faint.

Gallbladder rupture is a life-threatening emergency.

A ruptured gallbladder is a worst-case scenario; most animals with gallstones don’t have any signs of disease and live normal lives.

Diagnosis

To diagnose gallstones, a veterinarian will perform a thorough physical examination. The tummy will be felt (palpated), and signs of pain around the gallbladder area (the upper part of the belly under the last few ribs) will be checked. Bloodwork will likely be run to check for liver changes; increased bilirubin, calcium, or cholesterol in the blood; and to look for evidence of inflammation, dehydration, or infection. Next, x-rays will be taken to see if any stones are visible. Unfortunately, only about 50% of gallstones can be seen on x-rays. An ultrasound of the belly may also be needed. This allows the veterinarian to check the size of the gallbladder; look for signs of bile inside the belly; confirm gallstones; make sure the liver looks healthy; and see if the bile duct is blocked. These tests can also help the veterinarian determine what caused the stones so that steps can be taken to prevent more from forming.

Treatment

In all cases, treatment will depend on what signs your pet is experiencing. If the pet is not showing any signs of an issue, there likely isn’t any treatment needed other than watching and waiting. The veterinarian will probably want to monitor the pet periodically with bloodwork, x-rays, and/or ultrasound to ensure the stones don’t change or cause discomfort.

If your pet is showing signs of duct obstruction or pain, surgery to remove the gallstones and often the entire gallbladder may be necessary. If the gallbladder bursts, emergency surgery to remove it and uncontained bile from inside the belly is needed immediately. (Remember, a ruptured gallbladder is a life-threatening emergency.) Hospitalization and intensive care are often required after gallbladder surgery.

Sometimes medications that protect the liver, such as ursodiol or SAMe , will be prescribed to help keep the liver healthy. Antibiotics may also be given if an infection is suspected or if the gallbladder ruptured.

Prognosis and Summary

For pets that don’t show signs of gallstones, the long-term risk for issues is low. Bile duct obstruction may occur, but it’s not common.

For pets that need surgery, the chance for improvement is good, but gallbladder surgery can be risky. If bile leaks into the belly, pets can become extremely ill and may die. For pets that need emergency surgery because their gallbladder ruptured, chances of improvement are much lower than those whose gallbladder didn’t burst. Pets that survive the surgery may need to be hospitalized for a long time before they can safely be sent home to continue to improve.

If you suspect your pet has gallstones, call your veterinarian for a checkup. Fortunately, gallstones are not common, but the signs could be caused by something else that needs to be treated. If your pet was recently diagnosed with gallstones, be sure to follow all your veterinarian’s instructions and give all medications as prescribed. Contact your veterinarian about any questions or concerns, especially if your pet does not improve.

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