Successful surgical treatment of obstructive liver disease caused by a biliary calculus in a captive chimpanzee (Pan Troglodytes)

A 40-yr-old female chimpanzee (Pan troglodytes) presented with intermittent, short-duration episodes of nonspecific clinical signs that included lethargy and reduced responsiveness to external stimuli. Clinical examination and diagnostics suggested obstructive hepatic disease, which was confirmed by subsequent ultrasonographic examination. During routine laparotomy, a biliary calculus was removed from the distal common bile duct and the gallbladder was removed, which resulted in complete clinical recovery. The biliary calculus was analyzed as a mixed composition of predominantly cholesterol, bilirubin, and calcium.