Diagnostic Value of Plasma Biochemistry, Hematology, Radiography, and Endoscopic Visualization in Companion Psittacine Birds that Underwent Endoscopic Liver Biopsy: 28 Cases, 2007–2016
Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
Although liver disease is common among companion psittacine birds, the diagnosis of hepatic disease is challenging.1 Clinical signs are often nonspecific; hepatocellular leakage enzymes are not exclusive to hepatocytes; and up to 80% of hepatic tissue must be dysfunctional before clinical signs of hepatic failure become apparent.1,2 The correlation of plasma biochemistry and hematologic, radiographic, and endoscopically observed gross abnormalities with histologically confirmed hepatic pathology have not been extensively studied. A retrospective study was conducted from medical records of Psittaciformes at a veterinary teaching hospital from 2007 through 2016. Plasma biochemical, radiographic, and endoscopic visualization findings were classified as abnormal or normal. Each of these findings were compared to hepatic histopathology for agreement or disagreement. Statistical significance was based on the Kappa test for agreement and McNemar’s test for disagreement. On histopathology, 25 of 28 psittacine birds had liver lesions. Only 11 of 28 psittacine birds (39.3%) had clinical signs considered specific for hepatic disease. Gross changes on radiography or endoscopy agreed with histopathology in 57.1% and 53.6% of cases, respectively. Aspartate aminotransferase (AST) (48.1%), creatine phosphokinase (CPK) (73.1%), and albumin by protein electrophoresis (50%) showed highest agreement. No parameter had significant agreement, while disagreement reached significance for radiography, endoscopy, AST, lactate dehydrogenase (LDH), bile acids, total protein, cholesterol, triglycerides, uric acid, and glucose. Abnormalities of plasma biochemistry, hematology, radiography, and endoscopy are nonspecific and do not consistently agree with histopathology results. Reliable predictive value is lacking. Endoscopic liver biopsy is recommended to confirm clinical suspicion of liver disease.
The authors thank Deborah Keys, PhD, for statistical consultation, which was supported by the Pamela de Journo Fund.
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2. Jaensch S. Diagnosis of avian hepatic disease. Semin Avian Exot Pet Med. 2000;9(3):126–135.