With portosystemic shunting ,some of the blood by-passes the liver and enters directly into the systemic circulation. This by-pass has two major effects. Second, the blood supply to the liver is drastically decreased and therefore the liver does not get appropriate nutrients and will begin to become less functional. Congenital shunts are the result of abnormal development of the portal vein in the fetus. Patients with congenital shunts often develop some degree of liver dysfunction due to the decreased blood flow to the liver.
Acquired shunts are the result of severe liver disease and portal hypertension.
The clinical signs are a reflection of the effects of the absorbed toxins on the brain. Often, depression or stupor are the changes that owners notice. Since these toxins originate in the intestinal tract, signs often worsen after a meal. Many other nonspecific clinical signs such as failure to thrive, weight loss, poor appetite, urinary tract infection and behavioral changes have also been described. Diagnosing Portosystemic Shunts There are many methods of diagnosing portosystemic shunts.