Prognosis of Dogs Presented with Hyperbilirubinemia
Craig B. Webb, PhD, DVM, DACVIM (Small Animal), Colorado State University
In the Literature
Brough A, Caraguel C, Ciaravolo S, Stickney A. Clinical findings and assessment of factors associated with survival in dogs presenting with hyperbilirubinaemia: 115 cases in Victoria, Australia (2015-2020). Vet Rec Open. 2022;9(1):e42. doi:10.1002/vro2.42
The Research …
Significant disease is often present when bilirubin is increased enough to cause icterus (usually, >34 µmol/L [2 mg/dL]) in veterinary patients. Prehepatic (eg, immune-mediated hemolytic anemia), hepatic (eg, copper-associated hepatopathy), and posthepatic (eg, extrahepatic biliary obstruction) differentials should be included in initial assessment of hyperbilirubinemic patients.
This retrospective study described clinical presentation and outcome of dogs (n = 115) with hyperbilirubinemia from 2 referral practices in Australia and sought to identify factors associated with survival. Clinical signs at presentation were nonspecific; vomiting, anorexia, lethargy, and fever were most common. Median patient age was 9 years, but a wide range (10 months to 16 years) was represented. Most dogs underwent advanced imaging (ie, abdominal ultrasonography [66.9%], abdominal CT scan [10.4%]). Liver biopsy (21.7%), fine-needle aspiration (11.3%), and tissue or bile culture (13.9%) were also performed.
Hepatic icterus was most common (44.3% of cases), followed by posthepatic (36.5%) and prehepatic (15.7%) icterus. Fifty-three dogs (46.1%) survived to discharge, and median survival time for all dogs was 40 days. Prehepatic hyperbilirubinemia (eg, due to immune-mediated hemolytic anemia, posttransfusion hemolysis, tiger snake envenomation) was associated with a significantly higher risk for death compared with hepatic or posthepatic conditions.
Serum bilirubin ≥60 µmol/L (3.5 mg/dL) was associated with significantly decreased median survival time. This result supports the importance of hyperbilirubinemia in patient assessment and prognosis and suggests hyperbilirubinemia should be discussed with pet owners, regardless of underlying cause or disease process.
… The Takeaways
Key pearls to put into practice:
Hyperbilirubinemia indicates potentially significant disease, and the underlying cause should be determined quickly. Prehepatic, hepatic, and posthepatic differentials should be considered.
Prehepatic hyperbilirubinemia was associated with higher risk for death in this study. Prehepatic differentials can often be supported or excluded with a hematocrit test (ie, packed cell volume, total protein). Low packed cell volume with normal total protein is a strong indicator of RBC lysis.
A conversation with owners regarding prognosis should occur promptly in cases of hyperbilirubinemia. Severe elevations in total bilirubin and prehepatic hyperbilirubinemia are considered poor prognostic indicators of survival and may help owners make treatment decisions.
It is difficult to apply population statistics to individual cases. In this study, 41 dogs failed to survive to discharge, and 53 dogs were still alive when median survival (40 days) was calculated. Clinicians have a vital role in helping owners understand the implications of research when making treatment decisions for their pet.
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