Portosystemic Shunts

abnormal vascular pathways that carry blood from the portal vein into circulation throughout the body without being filtered through the liver.

Properly functioning portal veins carry blood from the stomach, intestines, pancreas and spleen to the liver. In the case of a shunt vessel, the liver is prevented from filtering and processing the blood of toxins and is deprived of needed pancreatically-produced substances. Thus a portosystemic shunt results in an underdeveloped liver that cannot effectively synthesize, metabolize, or detoxify.

There are two broad classifications of Portosystemic shunts derived from the location of the shunt vessel either contained within or outside the liver proper. Extrahepatic shunts can be single or multiple vessels that are located completely outside the liver and are more common in cats, miniature and small breed dogs. Most commonly congenital (present at birth), extrahepatic shunts can also develop as a result of chronic liver disease. Intrahepatic shunts, located within the liver proper, are congenital and more common in larger breeds of dogs.

Symptoms:

- Early onset (puppies)

- Slower than normal growth (smaller than they should be)

- Poor muscle development and hair coat

- Quiet demeanor (not playful like puppies)

- Behavioral abnormalities including circling & frequent disorientation, these changes are most often seen after eating

- Seizures

-Blindness

- Difficulty recovering from anesthesia or sedatives

- Abnormal liver function values

- Less common symptoms include:

- Excessive drinking and/or urinating

- Vomiting

- Diarrhea

- Excessive salivation is commonly seen in cats

Procedure:

Depending on the severity of clinical signs, a patient with a portosystemic shunt may need to be hospitalized to stabilize or control seizure activity. The surgical procedure for correction employs the use of either a vessel-constricting titanium ring or cellophane banding with the goal being to reduce blood flow through the shunted vessel, while redirecting the blood through healthy vessels and on to the liver.

Intrahepatic shunts may be best dealt with a staged attenuation procedure.

Following Portosystemic shunt surgery, close behavior monitoring and blood chemistry testing can help track progress.

Prognosis:

The prognosis for animals with portosystemic shunt attenuation is good. In most cases clinical signs are eliminated and the patients do not require medical therapy. It is very uncommon for blood chemistry values to return completely to normal values.

After Care:

Hospitalization:

- Your pet will need to stay until he is eating well and free of obvious abdominal discomfort. And can then be picked up during our regular business hours. There will be staff overnight to monitor your animal.

- When you get your pet home, place your pet in a cool/warm (season dependent), quiet and dark room. If you leave your pet alone, he/she will sleep and be comfortable. You can increase your pet’s anxiety by doting. Your pet will have adequate medication for pain so you do not need to worry about discomfort.

Medication:

– Antibiotics, lactulose and a low protein diet may be recommended for 3-6 weeks post surgery.

Food & Water:

- When you get your pet home, offer him/her a small amount of water. If your pet drinks it and does not vomit, then offer twice the original amount.

- Two hours later if no vomiting has occurred, offer ¼ of the amount of food in a normal meal.

- If your pet eats and no vomiting occurs in a 2-hour time period, then you may resume normal feeding(s).

- Please call Dr. Dew’s or your veterinarian’s office if your pet does not drink within the first 6 hours of being home or if vomiting occurs.

Rechecks:

– Your pet will need to be rechecked in7-14 days by Dr. Dew, please call 866-838-4282 to schedule this appointment.

- In 4-6 weeks your general practice veterinarian may repeat a chemistry screen and bile acid analysis. Pending those results, we may decrease or eliminate your pet’s medical therapy.

Exercise Restriction:

- Restricted to leash activity for 3 weeks.

Physical Therapy:

- None required

- Call Dr. Dew the week following the procedure with an update.

– Dr. Dew or your veterinarian may check incisional healing in 2-3 weeks.