Canine portosystemic shunts: an overview of diagnosis and treatment options

• Congenital portosystemic shunts are the most common congenital anomaly of the hepatobiliary system in dogs. • Hepatic dysfunction results from the presence of a portosystemic shunt, leading to a wide variety of clinical presentations of which hepatic encephalopathy is the most common. • Signalment, history and clinical signs may be strongly suggestive of portosystemic shunt as a diagnosis, but they are not conclusive and diagnostic short-cuts should not be taken. • Definitive diagnosis, and identification of concurrent or complicating problems, requires a combination of laboratory data (haematology and biochemistry, bile acid stimulation tests, resting serum ammonia, ammonia tolerance, urinalysis, coagulation assessment) and diagnostic imaging. • Medical management is generally instituted to stabilise patients prior to surgery. • In the absence of a known contra-indication to surgery such as portal vein atresia or multiple acquired secondary shunts, surgical attenuation or ligation is the treatment of choice.