Following are differential diagnoses for dogs presented with increased icterus.
Pre-hepatic causes (hemolysis)
Immune-mediated hemolytic anemia, primary or secondary
Blood transfusion
Non-immune–mediated
Drug-induced
Erythrocyte fragmentation (eg, caval syndrome, disseminated intravascular coagulation)
Erythrocyte membrane or enzyme defects (eg, hypophosphatemia, phosphofructokinase deficiency)
Infectious disease
Paraneoplastic
Toxin (eg, zinc, onion, garlic)
Hepatic causes (hepatocellular dysfunction)
Fibrosis
Inflammatory or infectious hepatopathy (hepatitis/cholangiohepatitis)
Neoplasia
Toxin or drug hepatopathy
Post-hepatic causes (cholestasis, defective biliary excretion)
Diseases of the biliary system
Biliary system rupture
Gallbladder disease
Cholelithiasis
Stricture
Infection
Inflammation
Neoplasia
Diseases outside the hepatobiliary biliary system
Enlarged regional lymph nodes
Pancreatitis
Neoplasia (pancreas, duodenum)
Intestinal disease or obstruction
*Bilirubin can be artifactually increased by lipemia and hemolysis
**Serum bilirubin values >1 mg/dL produce serum icterus; values >2 mg/dL produce tissue jaundice