Dogs with intrahepatic portal hypertension of congenital cause have distinct diagnostic findings compared to dogs with chronic hepatitis-related portal hypertension

Objective: To compare signalment, laboratory, and imaging findings in dogs with intrahepatic portal hypertension (PH) secondary to congenital hepatic disorders or chronic hepatitis (idiopathic or copper associated). Methods: This was a multi-institutional retrospective study (January 1, 2013, to August 25, 2024). Dogs were included if they had clinical evidence of PH (multiple portosystemic shunts, peritoneal effusion, or both) and evidence of liver dysfunction. Dogs were classified as having congenital disease or chronic hepatitis causing PH based on blinded review of liver histopathology. Categorical variables were compared with the Fisher exact test. Continuous variables were compared via the Mann-Whitney U test; variables with P < .2 were included in a multivariable model. Results: 39 dogs met inclusion criteria (16 congenital and 23 chronic hepatitis). Dogs with chronic hepatitis were older and had higher serum bilirubin, ALP, and GGT concentrations; lower serum albumin concentrations; and lower platelet counts compared to dogs with congenital disease. Dogs with congenital hepatic disease had lower MCV. Age and MCV remained significant on multivariable analysis. Hepatic parenchymal heterogeneity on abdominal ultrasound was reported more frequently in dogs with chronic hepatitis. Conclusions: Liver biopsy remains the gold standard for diagnosing the cause of intrahepatic PH in dogs. However, age, specific clinicopathologic abnormalities, and hepatic ultrasonographic heterogeneity might help clinicians differentiate these conditions when histopathology is unavailable. Clinical Relevance: When liver biopsy is unavailable, clinicians evaluating dogs with PH might use age, MCV, albumin, platelet count, cholestatic enzyme activities, and hepatic ultrasonographic echotexture to prioritize congenital versus chronic hepatitis etiologies and guide prognostic counseling.