EXPRESS: Extrahepatic biliary obstruction secondary to right-sided diaphragmatic hernia in a juvenile cat

Case summary A 10-month-old spayed female European Shorthair cat was presented for a 3-week history of progressive vomiting, lethargy and hyporexia. Complete blood count was unremarkable, while serum biochemistry revealed increased alanine aminotransferase, gamma-glutamyltransferase (GGT), and total bilirubin at the upper limit of the reference interval. Physical examination identified mild dehydration and marked cranial abdominal distension. Abdominal ultrasonography demonstrated gastric atony, severe intra- and extrahepatic biliary duct dilatation, a distended gallbladder and focal duodenal dilatation at the expected location of the major duodenal papilla with a hyperechoic interface producing distal acoustic shadowing, raising suspicion of a duodenal foreign body causing papillary obstruction. Emergency exploratory laparotomy revealed a right-sided dorsolateral circumferential diaphragmatic hernia containing the proximal descending duodenum, pancreas and omentum. Reduction of the herniated viscera and herniorrhaphy were performed, and biliary decompression was achieved by gentle gallbladder expression alone. A history of blunt trauma was reported only after surgery, supporting a chronic, presumptively traumatic hernia. The postoperative course was complicated by the development of cervicothoracic subcutaneous emphysema, pneumomediastinum and a small pneumothorax, managed conservatively. The cat’s appetite returned and it was discharged 3 days postoperatively with residual subcutaneous emphysema. At 1 and 5 months postoperatively the owner reported no gastrointestinal or respiratory signs. Relevance and novel information This report describes an unusual cause of feline extrahepatic biliary obstruction secondary to a chronic, presumptively traumatic diaphragmatic herniation, resulting in mechanical obstruction at the level of the major duodenal papilla. Recognition of this rare mechanism may prevent misdiagnosis as primary hepatobiliary disease.