Laboratorial diagnosis of biliary peritonitis secondary to cystic duct rupture in a dog - case report

Biliary peritonitis results from damage to the biliary tract, causing exposure of the peritoneal surface to bile with consequent tissue inflammation. Effusion analysis is essential, as it can provide definitive findings for diagnosis. An adult female, mixed-breed dog was attended presenting jaundice, ascites, emesis, dyspnea, hypothermia, and hypotension. The most significant laboratory findings were leukocytosis due to neutrophilia with a left shift, and serum activities of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) above the reference values. Abdominal effusion analysis showed a predominance of intact neutrophils, macrophages containing bluish intracytoplasmic material, golden-yellow pigments on the background of the slide and free and intracellular golden crystals, both suggestive of biliary origin. Total bilirubin concentration in abdominal effusion showed value more than five times higher than serum concentration, indicating, in association with the other findings described above, biliary peritonitis. Abdominal ultrasound revealed a slightly distended gallbladder, with no other significant changes. The dog was euthanized, and necropsy revealed an irregularity in the cystic duct consistent with rupture. The present case highlights the relevance of analyzing abdominal effusion for the diagnosis of biliary peritonitis, especially when ultrasonographic findings are not conclusive.