Portal shunting is an abnormality of the blood vessels of the liver (portal system) that causes some or all of the blood from the intestines to be shunted around (bypass) the liver and to go directly into the general circulation. A very serious consequence of portal shunting is the increase in blood ammonia levels after eating. Accumulation of blood ammonia seriously impairs brain function and may cause seizures, coma, and death.
Portal shunts can be present at birth (congenital) or develop later in life (acquired). In all cases, however, portal shunting is a serious disorder.
Important Points in Treatment
1. Portal shunting is treated surgically and/or medically. For surgery to be beneficial, the shunt must be in an operable location. Often shunts cannot be reached for surgical correction. While some pets have lived for several years with portal shunts, the condition is usually terminal when surgery is not possible.
2. Portal shunting is a very complicated disease, and diagnosis and treatment involve extensive laboratory tests. Highly specialized x-ray techniques use dyes that are visible on radiographs (x-rays) to find the shunts. Many affected animals are referred to specialists for treatment.