Gallstones in Cats

Though gallstones are rare in cats, the presence of large stones is a medical emergency as the stones can block the bile from being released and cause problems with the liver, digestive system and the kidneys.

The cat's gallbladder is a small, balloon-shaped organ that is located in the lobes of the liver. Its primary function is releasing bile into the digestive tract to aid in the digestion of food. Cholelithiasis is a condition that causes small stones, or choleliths, to form in the gallbladder. These stones are typically made of calcium carbonate mixed with other secreted substances and minerals.

Symptoms may be mild or not present at all until the gallstone blocks the flow of bile from the gallbladder. Typical symptoms include:

• Lack of appetite
• Weight loss
• Vomiting
• Abdominal pain
• Jaundice, which will present with yellowing of the inner ears, whites of the eyes and mucous tissues
• Fever
• Lethargy
• Frequent changing positions or stretching
• Frequent wandering or pacing

Types

Gallstones can be divided into two different types, which are categorized depending on the minerals that combine with calcium carbonate to form them:

• Black-pigment gallstones are composed of bilirubin polymers
• Brown-pigment gallstones are composed of calcium bilirubinate

There are several different reasons why cholelithiasis occurs in cats. These causes include:

• Malfunction of the gallbladder
• Bile sludging, which causes the bile to thicken and slow down
• Bacterial infection
• Tumor
• Nutritional imbalance, such as consuming too much calcium or cholesterol

The veterinarian will need the cat's complete health history, which will include any history of gallstones, a detailed list of all of the cat's systems and an approximate date when the symptoms first began. Because many of the symptoms of gallstones are also present with more serious diseases, such as liver disease, gallbladder inflammation, bile duct inflammation and pancreatitis, these conditions will need to be ruled out.

A complete blood count, biochemical profile and urinalysis will be ordered by the veterinarian. These labs will look for the presence of an infection that could be causing the gallstones and help to rule out other conditions or diseases. Because most gallstones don't contain enough minerals to be detected on a radiograph, X-rays are rarely done but could be ordered if the veterinarian suspects another condition that is identifiable by an X-ray. 

Ultrasound imaging will be done of the cat's abdominal area. The ultrasound will look for the presence of gallstones, inflammation of the liver, blockage of the bile duct, thickened gallbladder walls or an oversized bile duct tract. An ultrasound can detect gallstones that are two millimeters or larger in size.

No Treatment

Small gallstones that aren't causing symptoms or digestive problems may not need any treatment. These stones are typically found during an ultrasound for another condition, such as pregnancy.

Medication

Antibiotics will be prescribed to the cat to clear infections or bacterial complications that are causing the gallstones to form. Antibiotics may also be prescribed before surgery in order to prevent infection from occurring after surgery. Ursodeoxycholic acid may be prescribed twice a day in order to dissolve small gallstones that aren't blocking the bile duct. S-Adenosylmethionine, or SAMe, may also be given in order to improve bile production and function of the liver.

Intravenous Supplements

In addition to medication, the doctor may recommend that the cat receives supplements intravenously. Vitamin K1 will be given to treat jaundice and vitamin E will help reduce inflammation in the liver and gallbladder.

Surgery

If the gallstones are blocking the bile duct, are causing cystic duct obstruction or are causing gallbladder inflammation, surgery will be necessary. The veterinarian will determine the best surgery for the cat's individual situation. If gallstones have formed in the past, the veterinarian may elect to remove the gallbladder from the cat. If this is the first time gallstones have formed, the veterinarian may remove only the gallstones from the gallbladder or bile duct opening, retaining the gallbladder. 

During surgery, the cat will be placed under general anesthesia. An incision will be made in the cat's abdomen and gallbladder. The gallstones will be removed before the gallbladder is closed with dissolvable sutures. Gallbladder surgery carries a risk of infection and of gallstones forming once again in cats who only have the gallstones removed rather than the entire gallbladder.

With proper diagnosis and treatment, the prognosis is positive after gallstone treatment. The cat will need to follow up with the veterinarian two weeks and four weeks after surgery. The veterinarian will look for any signs of infection and remove sutures when necessary. An Elizabethan cone will need to be worn in order to prevent the cat from licking or biting its sutures. Any redness or pus at the incision site or fever may indicate infection. If these signs occur, the cat should be brought back to the hospital immediately.

Regular ultrasounds or blood tests may need to be done to monitor the function of the liver and the bile system. Because the gallbladder helps digest ingested fat, a low-fat, high-protein diet may be recommended by the veterinarian that will need to be continued throughout the cat's life.