Comparison of diet, lactulose, and metronidazole combinations in the control of pre‐surgical clinical signs in dogs with congenital extrahepatic portosystemic shunts

BACKGROUND: Hepatic supportive diet (HSD), lactulose, and antimicrobials are medical treatments for dogs with congenital extrahepatic portosystemic shunts (cEHPSS). The relative contribution of these treatment components is currently unknown. OBJECTIVES: To determine which treatment combinations are most efficacious in pre‐surgical control of clinical signs of cEHPSS in dogs. ANIMALS: Thirty‐six dogs with untreated cEHPSS. METHODS: Three‐arm randomized clinical trial. At inclusion (T0), dogs were divided into 3 groups: HSD (n = 12), HSD + lactulose (n = 12), or HSD + metronidazole (n = 12) and received the randomized treatment for 4 weeks (T1) followed by combined treatment of HSD + lactulose + metronidazole for 2 weeks or until cEHPSS attenuation (T2). Clinical score as well as fasting ammonia (FA) and C‐reactive protein (CRP) concentrations were compared among groups and time points. RESULTS: Thirty‐four dogs were evaluated. Thirty‐four dogs reached T1 and 29 dogs T2. At T1, clinical scores decreased in the HSD + lactulose (n = 11; P = .001), but not in the HSD (n = 8; P = .96) and HSD + metronidazole (n = 10; P = .06) groups. Adding metronidazole to HSD + lactulose (n = 11) did not result in further clinical score improvement (T2; P = 1.000). Moderate and weak correlation between clinical score and FA and clinical score and CRP was present (ρ = .35, P < .001; ρ = .27, P = .01, respectively) with FA decreasing over time on medical treatment (P = .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Combined HSD + lactulose seems sufficient for pre‐surgical cEHPSS stabilization unlike sole HSD or HSD + metronidazole. Medical treatment of cEHPSS clinical signs decreases FA.