Case Study

Portosystemic shunt in a 1 year old M Maltese dog

A 1-year-old M Maltese dog was presented due to dark colored urine and minimal appetite. Physical examination was unremarkable. Urine was clear and yellow in appearance and on analysis showed normal pH and specific gravity, 3+ bilirubinuria, and the presence of bilirubin and ammonium biurate crystals. The only abnormality on CBC was thrombocytopenia. Blood chemistry showed an icteric serum, elevated ALP, ALT, and AST activity, hyperbilirubinemia. Both pre-and postprandial bile acids were markedly elevated.

A 1-year-old M Maltese dog was presented due to dark colored urine and minimal appetite. Physical examination was unremarkable. Urine was clear and yellow in appearance and on analysis showed normal pH and specific gravity, 3+ bilirubinuria, and the presence of bilirubin and ammonium biurate crystals. The only abnormality on CBC was thrombocytopenia. Blood chemistry showed an icteric serum, elevated ALP, ALT, and AST activity, hyperbilirubinemia. Both pre-and postprandial bile acids were markedly elevated.

DX

Deep portocaval shunt or porto azygos shunt

Sonographic Differential Diagnosis

Deep portocaval shunt or porto azygos shunt appears surgically correctable.

Image Interpretation

The gastric axis in this patient was displaced cranially due to small liver size. The gallbladder was mildly prominent, however no excessive debris was noted. The liver was structurally unremarkable other than the small size. No significant increase in portal markings were noted. No intrahepatic shunts were noted. However a large tortuous 0.7cm wide portocaval or porto azygos shunt was noted in this patient deviating from the portal vein approximately 1.5 cm from the portal hilus traversing ventrally and turning to continue along the gastric axis and emptying into either the caudal vena cava at entrance of the diaphragm or possibly into the azygos vein. This could not be adequately ascertained however was entirely extrahepatic from a sonographic perspective. The residual portal vein after the shunt deviation measured 0.3cm. The caudal vena cava measured 0.6cm at the portal hilus and the aorta measured 0.6cm as it traversed the diaphragm which would be suggestive of a porto azygos shunt however a deep portocaval shunt can also present these ratios. The liver width measured 1.7cm in short axis.

Outcome

The patient was treated with L/D diet, lactulose, and neomycin before undergoing surgery for shunt attenuation and liver biopsy. The anomalous vessel was identified caudal to the stomach and a 7mm ameroid constrictor was placed. No information is given in the surgery report regarding the course of the vessel. No biopsy results are available. The patient recovered from procedures without event and was discharged with metronidazole, lactulose, and NSAIDS. At the suture removal appointment the patient was doing well.