Bile duct obstruction, or cholestasis, occurs when bile isn't able to properly flow from the gallbladder into the small intestine. When the bile is prevented from leaving the bile duct, a cat may become very ill as it can't get the proper nutrition it needs. Excess red blood cell breakdown products affect the lungs, brain, kidneys and heart.

Bile is a fluid that aids the cat's body in the digestion of food. It is made in the liver and is stored in the gallbladder. After eating, bile travels through the bile duct into the intestines, where it helps break down the food in order for the cat to get the needed nutrients and deposit the excess as waste.

Symptoms of the condition may vary, depending on the condition or disease that is causing the obstruction to occur. 

Bile duct obstruction isn't a disease in itself, but rather a secondary condition that arises from another disease or condition. 

The veterinarian will ask for the cat's complete health history, details about when the symptoms began and any possible trauma or recent surgeries that could have caused the obstruction to occur. Next, a complete blood count, a urinalysis and a biochemistry panel will be taken. These tests will help the vet to determine what underlying diseases may be causing the obstruction and any other problems, such as anemia, that resulted due to the blockage. If the labs show that the cat's bilirubin levels are high, this indicates that waste products are building up in the bloodstream. A stool analysis will help the vet determine if normal amounts of bilirubin are leaving the body. Too much bilirubin in the body is indicative of an obstruction of the bile duct. The cat's liver enzymes will show if liver damage or disease is present that are causing the obstruction. A urinalysis will help the vet determine how the kidneys are reacting to the obstruction.

The veterinarian may also perform an abdominal ultrasound or x-ray to look at the pancreas, gallbladder, and liver. These tests will allow the veterinarian to see any inflammation, growths or scar tissue that is causing the obstruction. Exploratory surgery may be done if the labs, ultrasounds, and x-rays don't give conclusive results as to what is causing the obstruction.

Treatment of bile duct obstruction depends on the underlying disease or condition that caused the blockage to occur. 

Bile duct obstruction needs to be treated promptly as it can result in severe damage to the liver and gallbladder. The cat will need to follow-up as directed by the veterinarian after initial treatment in order to monitor their underlying condition. If dietary restrictions were recommended, the cat will need to follow these in order to prevent the duct from becoming blocked once again. Cats who experience bile duct obstruction have a good prognosis as long as the underlying conditions are treated promptly and are managed under a veterinarian's care.