Symptoms and Treatment of Gallstones

Also known as gallstones or cholelithiasis, these are formations in the gallbladder that can end up blocking it, posing a risk to the dog's life.

Luckily, this type of stone isn't very common in dogs, but it's important to know about them, since they can be one of the causes of jaundice (yellowish mucous membranes) and, depending on how severe the blockage is, can be fatal for our dog.

How does the biliary system work?

Bile is a secretion produced by the liver that travels to the gallbladder, where it's stored. Among other functions, this organ digests fat, helping absorb nutrients. A failure in this system will have effects throughout the whole body. Bile contains:

• Mainly cholesterol.
• Bile acids (also called bile salts, essential for digesting fats).
• Bilirubin (a byproduct of red blood cell breakdown).
• Water.
• Body salts (such as potassium and sodium).
• Copper and other metals.

Once fatty food reaches the duodenum (the first part of the small intestine), it triggers contractions in the muscular portion of the gallbladder, which releases its contents into the bile duct and afterward into the duodenum.

What are gallstones?

Gallstones are deposits of cholesterol, bilirubin, oxalate, or calcium. These stones can form in several locations. In the gallbladder, causing a blockage — known as cholelithiasis or gallstone disease — or in the cystic duct or common bile duct. So, choledocholithiasis refers to stones located in the common bile duct.

Meanwhile, the liver keeps producing bile to the point that the extrahepatic ducts overflow, starting a toxic process affecting hepatocytes (liver cells), harming their function and causing systemic symptoms.

How do gallstones form?

Several causes are involved in their formation. Likewise, the clinical picture they cause varies, depending on the size and how much blockage they cause in the bile ducts.

Arias et al. (2001) state that the causes of cholelithiasis can vary, highlighting dehydration, gallbladder infections, and bile stasis as possible causes. In other cases, inflammation or infection occurs after the stones form, as a result of them — peritonitis.

Which breeds can have gallstones?

Although it's not a common problem, some breeds do seem more predisposed, such as the Miniature Schnauzer or Poodle. In dogs it's an uncommon condition, most often affecting animals over two years old.

Symptoms of gallstones in a dog

Some dogs with this type of stones show no symptoms at all — in these cases, the stones are found by chance. Others, on the other hand, show a clinical picture that includes symptoms such as the following:

1. Vomiting, nausea, and possible retching.
2. Diarrhea.
3. Decreased appetite.
4. Acute pain in the upper abdomen.
5. Unusual posturing due to this pain.
6. Fever.
7. Lethargy.
8. Jaundice, meaning yellowish discoloration of the mucous membranes and skin.

Are gallstones dangerous?

Gallstones can cause a blockage of the bile ducts. Depending on where they're located, they'll block the flow of bile from the liver to the intestine, causing a serious health problem in two ways. First, bile buildup in the body can damage various organs and/or cause peritonitis.

On the other hand, since bile doesn't reach the digestive system, fats and fat-soluble vitamins can't be digested or absorbed. In the most severe cases, the stones can end up rupturing the cystic or common bile duct, or even the gallbladder itself, releasing bile into the abdominal cavity and causing peritonitis, which puts the dog's life at serious risk.

The ongoing presence of liver stones can lead to hepatic encephalopathy, in which neurotoxins are released into the blood, seriously affecting astrocytes and neurotransmitters.

The organ becomes unable to carry out its anabolic, catabolic, or excretory functions for many compounds, many of them neurotoxic; patients quickly develop neurological signs such as seizures, ataxia, lack of coordination, and disorientation.

How are gallstones diagnosed?

The basis for determining a gallbladder problem is bloodwork, specifically a chemistry panel, where certain liver enzymes will show abnormal levels, such as GGT, along with triglycerides, bile acids, ammonia, and conjugated bilirubin.

Ultrasounds and X-rays are also done. Ultrasound is a fairly diagnostic additional test, since it can show the gallbladder's contents and shape, as well as the presence of abdominal peritonitis.

More specific tests that can be harder to access due to cost are an MRI or CT scan. The issue is that these aren't available at every vet clinic, though in Spain there are now many clinics and hospitals with this equipment. That said, we'll first try the more affordable additional tests, since these give us a lot of information.

Treatment

Depending on the size and severity of the gallstones, either surgery or conservative medical treatment will be recommended. For small amounts of biliary sludge, treatment with medication aimed at dissolving them is recommended, along with controlling pain and symptoms. Dissolving the stones can be done with ursodeoxycholic acid. Depending on severity, they'll need fluid therapy (lactate-free) to hydrate the patient, and liver protectants such as SAMe.

Surgery is reserved for dogs showing severe symptoms/complications or who don't improve with medication. This involves removing the gallbladder, known as a cholecystectomy, or removing the stones, known as a choledochotomy. The outcome is usually good, and the prognosis is positive.

To adjust treatment, the vet will need to figure out the underlying cause of the stone formation. If peritonitis is present, that fluid should be removed as much as possible, along with strong antibiotic coverage, such as fluoroquinolones like enrofloxacin or marbofloxacin, metronidazole, etc.

Recovery requires a specific, low-fat diet, along with medications appropriate to the symptoms present. Carrot, rice, oats, or chicken are some of the ingredients we can include in a homemade meal if we choose to cook at home.

Giving a liver-specific diet, such as kibble formulated for liver conditions, is also a valuable part of treatment. Many brands already sell these. That said, we can ask our trusted vet about this.