Arteriovenous Malformation of the Liver in Dogs
Intrahepatic arteriovenous (AV) fistula is a congenital based condition that is uncommon in most cats and dogs, but it can also develop through surgical injury, trauma, and abnormal tissue or bone growth (neoplasia). When it occurs abnormal passages develop between the proper liver (hepatic) arteries and the inner liver (intrahepatic) portal veins.
This acute illness can be addressed with fair results when a proper diagnosis has been settled on. Most treatment will be on an outpatient basis and will include a planned diet, dietary restrictions, and long term observation.
The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.
Symptoms and Types
Dogs that suffer from AV fistula may show lethargy, anorexia, vomiting, diarrhea, weight loss, excessive thirst (polydipsia), dementia, and abdominal swelling. There are several other signs of AV fistula, such as:
- Ascites, congenital heart malformations, hemorrhages, abnormal portal vein coagulation (thrombosis), protein loss in the kidney (nephropathy), intestinal abnormality (enteropathy) hypertension, liver disease, and cirrhosis of liver
- Or those affecting the central nervous system: distemper and other infectious disorders, lead poisoning, water on the brain (hydrocephalus), idiopathic epilepsy, metabolic disorders, brain degeneration associated with liver failure (hepatic encephalopathy)
There is not a breed that shows a higher predisposition than another. Hepatic AV is a vascular (vessel) malformation that is genetically determined during the embryonic stage of development, also referred to as embryologic anlage. Most conditions present in young dogs, but in some cases, surgical injury, traumas, or tumor growth (neoplasia) can lead to the problem.
The disorder can be tested by using complete blood count (CBC), biochemistry, and urinalysis techniques; coagulation tests, abdominal (peritoneal) fluid analysis, evaluation of bile acids (digestive secretion from the liver), X-rays, ultrasounds, liver biopsies, and exploratory laparotomies (incision into the abdominal wall) are other exams that may help diagnose the liver malformation.
While some pets will require surgical care, most can be treated at home with nursing care. Modifications to the diet will often include restrictions on nitrogen intake and sodium. Hydration and electrolyte disturbances will also be addressed and treated. Drugs that rely on liver biotransformation should be avoided, along with any drugs that will react with GABA-benzodiazepine receptors (the transmitters that inhibit anxiety and over excitement). Veterinarians will commonly prescribe histamines for blood pressure reduction, and diuretics (furosemides) to relieve excess fluid.
Living and Management
It is important to monitor the biochemistry of the dog every few weeks, and then every few months following the initial treatment routines. Prognosis is fair for the dog when it is properly treated, although the dog will require ongoing monitoring and treatment to address any health issues that may arise.
As the health issue is mostly congenital in nature, there are no preventative measures to consider.
The condition of being drowsy, listless, or weak
To slow something down or cause it to stop
Relating to a disease of unknown origin, which may or may not have arisen spontaneously
Any growth or organ on an animal that is not normal
A medical condition involving excessive thirst
An in-depth examination of the properties of urine; used to determine the presence or absence of illness
A type of medical condition in which thrombus is created within the blood vessels
High blood pressure
Referring to the liver
The amount of pressure applied by the blood on the arteries.
The fluid created by the liver that helps food in the stomach to be digested.
Term used to imply that a situation or condition is more severe than usual; also used to refer to a disease having run a short course or come on suddenly.
Something having to do with an embryo or the development of an embryo
A disease of the brain of any type
The abdominal wall is a group of bones, muscles, and vital tissues that make up the wall around the organs in the abdomen. Inside these bones, muscles, and tissues is a cavity, and the cavity is what houses the vital organs found inside the abdomen. The abdominal wall is vital for protection of these organs.
A condition of frequent or recurring seizures that are not of a system origin
A condition in which fluid is found inside the brain; water on the brain