EXTRAHEPATIC BILIARY TRACT OBSTRUCTION (EHBO)
In both dogs and cats Bile is produced in the Liver, it is secreted from the  Bile Canaliculi (small ducts within the Liver) into larger ducts before it then enters the  Bile duct and comes to be stored in the Gallbladder. From here the Bile drains through the Common Bile Duct which then empties into the Duodenum (The first part of the Small Intestine).Â
EHBO is the blockage of normal Bile flow from the Liver to the Intestinal Tract.
Edema from perioperative handling of the Pancreas
Pancreatic, Bile Duct and Intestinal Neoplasia
What are the clinical signs of EHBO?
Clinical symptoms of EHBO are often nonspecific and can be the same as other abdominal conditions, in addition the signs can wax and wane and therefore patients are often not presented to a vet until icterus develops.
Icterus i.e Jaundice (Yellow discolouration to the mucus membranes, skins and sclera) usually present within 24hrs.Â
Blood Work - When the Bile Duct is obstructed serum levels of Bilirubin will be increased, and due to this the Liver enzymes (ALT & ALP) will also be increased. In severe cases the kidney values (UREA & CREA) will also be elevated and clotting times prolonged.
Radiographs - Useful in identifying stones within the biliary system and other abdominal disorders that could be contributing to the EHBO. Â
Ultrasound - Abdominal ultrasound is a recommended diagnostic technique in all cases when the patient is suspected of either bile duct obstruction or disease of the Gallbladder.
The main aim = Confirm diagnosis, establish a patent biliary system and minimise post-operative complications.Â
EHBO is almost always treated by surgical intervention which involves either removing the obstruction or bypassing it completely. Biliary-enteric anastomoses (cholecystoenterostomy) or rerouting bile from the Gallbladder to the Small Intestine will establish patency of the bile duct and help resolve clinical symptoms.Â
To ensure the outcome is positive early detection and quick resolution is needed as other metabolic issues can arise the longer a obstruction is present. Survival rates following surgery can be anywhere from 40-70%.Â