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Liver Shunt - Constrictor Ring Application & Other Treatments

What Is A Liver Shunt?

The portal vein collects blood from the spleen, pancreas, and gastrointestinal system and takes it to the liver, removing other byproducts. The liver shunt occurs when abnormal functioning occurs in the portal vein, its branches, another vein, and allowing the blood to bypass, around the liver, or shunt. In many cases, the liver shunt is by a birth defect known as a portosystemic shunt. However, multiple small shunts can be formed due to cirrhosis's severe liver disease.

Formation Of Congenital Portosystemic Shunt

The fetus of mammals has a large shunt known as ductus venosus, which carries the blood easily towards the fetal liver and then to the heart. There are two major causes due to which portosystemic shunt develops in mammals.

  • The ductus venosus fails to collapse at the mammal's birth, and it remains open and intact even when the fetus does not need it.
  • Due to the blood vessel development abnormally does not close with the ductus venosus.

Clinical Signs Of A Liver Shunt

  • Stunted Growth
  • Poor Muscle Development
  • Abnormal Behaviors
  • Head Pressing
  • Diarrhea
  • Weight Loss
  • Constipation
  • High Amount Of Drinking And Urinating
  • Vomiting
  • Recurrent Kidney Stones And Infections
  • Bladder Infections And Stones

Diagnoses Of Liver Shunt

The diagnosis is based on the patient's clinical signs and medical history. Below are the common diagnostic tests:

  • Complete Blood Count (CBC) & Serum Chemistries: Typically, the abnormal findings include anemia, low blood urea nitrogen and albumin, high liver enzymes, and smaller red blood cells.
  • Urinalysis: There are chances of urine dilution and infection in the urine. Plus, the urine will have small crystals known as ammonium biurate crystals.
  • Bile Acid Test: The dogs with liver shunts have raised bile acids. However, the dog will be normal, but the test results will be abnormal, and the tests can be repeated for at least 3 to 4 weeks.

Liver shunts increase the production of bile acid concentrations in the dog's blood because the liver does not have any chance to remove the chemicals after absorption.

High Risk Of Liver Shunts Among The Dog Breeds

The dog breeds, including old English sheepdogs, Yorkshire terriers, Irish wolfhounds, beagles, cairn terriers, have increased chances of portosystemic shunts. This is because the small breed dogs are prone to extrahepatic shunts, which results in the blood vessels outside of the liver. On the contrary, the larger breeds will have intrahepatic shunts, which create abnormal blood vessels but on the inner side of the liver. However, the extrahepatic shunts are tougher to repair than intrahepatic shunts.

Portosystemic Shunt Treatment

The dogs with liver shunts are stabilized with the medications and diet to reduce the number of toxins absorbed in the large intestines. In addition, those severely ill dogs should go for intravenous fluids to stabilize their blood sugar level. Plus, the medications include diazepam to prevent seizures.
Common medical procedures include the following:

  • Dietary Changes: The ultimate goal is to reduce the protein inside the diet and feed the pet a high-quality diet.
  • Lactulose: It is crucial to check the large intestine's pH level to administer the sugar. The absorption of ammonia and toxins will make the environment unfavorable for the bacteria.
  • Antibiotics: The best way to prevent the bacteria in the intestine is to use antibiotics. Also, it will reduce the bacteria growth in the large intestines.

What Does Liver Shunt Surgery Entail?

Many surgeons use an ameroid constrictor to close down the liver shunt. This is a metal band with a casein ring found in the milk. The inner ring will absorb the abdominal fluid and swell up gradually to shut down the scar. The shunts will close after a few weeks.
The other surgical treatment for liver shunts includes the cellophane bands to persuade inflammation and shut down the liver shunt. Besides this, the intravascular occlusive and clot-inducing apparatuses are suitable for liver shunt. The treatment will cost $3,500.

How Effective Is The Surgical Treatment?

The surgery is effective as it provides healthy and long life to the dogs. After placing the ameroid constrictor, the survival rate of the pet is more than 95 percent. Likewise, the pet will be normal after four to eight weeks of the surgery, but a minor percentage of the dogs have developed the acquired shunts, so the diet should be protein-restricted.

Post-Surgical Management

Feeding the pet with a diet that does not involve protein for at least 6 to 8 days is crucial. After the blood test appears normal, your dog should be consuming a high-quality diet. Moreover, it is important to add lactulose to the diet of dogs after some weeks of the surgery. The liver will start growing once the shunt closes down, and it will normally be functioning. Also, the size will be normal after 2 to 4 months. Plus, blood tests are taken repeatedly to monitor the functioning of the liver.