Portosystemic Shunts and Other Vessel Abnormalities
Portosystemic shunts can develop as part of an illness. These are known as acquired shunts. They can be caused by high blood pressure in the vessels that enter the liver. This can have an effect of resisting the blood flow. New vessels will open to bypass the liver and connect to the blood system of the rest of the body as the blood pressure is lower. Acquired shunts are seen more commonly in dogs than in cats and usually in older animals. The symptoms include vomiting, ascites which is an accumulation of fluid in the abdomen, diarrhea and excessive thirst. Tests will need to be performed to identify abnormalities that can be associated with the underlying liver disease. Medication may be prescribed. A band may be placed around the caudal vena cava which can slightly raise the blood pressure outside the liver and reduce shunting. The prognosis after this procedure can be favorable.
Poisons Affecting the Liver
One of the functions of the liver is to metabolize drugs. Because of this certain drugs have been associated with liver dysfunction. The symptoms and effects are dependent on the drug and the dosage. Generally, the veterinarian will monitor the dog for any changes or decreased liver function. There are other substances that are toxic to the liver. These include herbicides, fungicides, insecticides, heavy metals, blue-green algae, amanita mushrooms, alfatoxins which are produced by molds, and rodent poisons. These substances can cause severe liver damage which can be life threatening. If the dog has any access to any toxic substance, veterinary advice should be sought immediately. Access can include but is not limited to ingestion of a poison, accidental overdose of medication or an adverse reaction to medication. The veterinarian may be able to minimize the absorption of the toxic substance. This may be done by the administration of activated charcoal, pumping the stomach, administration of the appropriate antitoxin or inducing vomiting.