What is Liver Fistula?
A liver fistula is a malformation of the liver, often caused by a congenital defect. Symptoms usually present early in life for cats and other companion animals. The condition is also known as hepatic arteriovenous (AV) malformation and arteriovenous fistula, as well as liver fistula. When AV occurs, abnormal passages develop between the arteries and veins in the liver. This causes issues with blood pressure and blood flow within the liver. It can result in poor liver function, which affects numerous other bodily systems, causing a variety of symptoms. Liver fistula requires a veterinary diagnosis to confirm the condition and may require lifelong treatment. If your pet is exhibiting symptoms of liver fistula, seek medical attention as soon as possible.
Symptoms of Liver Fistula in Cats
Liver fistula can cause a variety of symptoms in cats. It can affect the central nervous, urinary, and gastrointestinal systems. It may also cause issues with the cardiac system. The severity of the symptoms will vary from cat to cat and may increase if AV goes untreated.
- Confusion or dementia
- Abnormal behavior
- Tremors or seizures
- Increased thirst
- Lack of appetite
- Blood in urine or feces
- Nausea, vomiting, and diarrhea
- Weight loss
- Poor growth
- Abdominal swelling, bloating, or fluid retention
- Pain and related vocalizations
- Heart rate irregularities
- High blood pressure
- Liver cirrhosis
- Fainting or collapse
Causes of Liver Fistula in Cats
Hepatic arteriovenous malformations are primarily caused in utero and are present at birth, although it can develop later in life due to injuries or traumas. Certain species that are more likely to have a congenital liver malformations and male cats are at a higher risk. Like many congenital defects, the exact cause of liver fistula is unknown. Common causes of liver fistula in cats and other companion animals include:
- Congenital or birth defect
- Genetic disorders
- Liver trauma or injury
- Biopsy lesions
- Surgical injuries
- Certain cancers
Diagnosis of Liver Fistula in Cats
Symptoms of liver fistula are similar to general symptoms associated with all liver disease and dysfunction. Your veterinarian will require multiple diagnostic methods to confirm AV as the cause of your pet’s condition. Be prepared to discuss your pet’s medical history, any recent surgeries or medical procedures, and the symptoms you have observed. A full physical examination will also be conducted. Abdominal swelling or bloating can often be identified during the physical examination. Blood and urine samples will also be collected. Your cat may need to fast for a 12 hour period to provide the necessary blood samples to confirm a liver disorder. Blood testing will include tests for serum bile acid concentration, clotting ability, and glucose levels. A urinalysis will also be completed.
Diagnostic imaging techniques will play a major role in determining if liver fistula or other conditions are causing the cat’s symptoms. Ultrasonography, magnetic resonance imaging (MRI), and other techniques may all be employed to determine the type of issue, how it is affecting other bodily systems, and the extent of the malformation. In some cases, exploratory surgery or liver biopsy may be necessary to complete the diagnosis.
Treatment of Liver Fistula in Cats
Cats with liver fistula can often be treated with minimally invasive methods. In some cases, hospitalization may be required until the cat’s condition can be stabilized. Many treatments can be completed on an outpatient basis and will require minimal time in the veterinary office or hospital. Some common treatments for liver fistula include:
Intravenous (IV) Fluids
Fluid therapy is often required for patients who are experiencing poor liver performance. Gastrointestinal issues like vomiting and diarrhea can increase dehydrations risks and require fluid treatments. IV fluids are often provided on an inpatient basis but do not necessarily require hospitalization. This common treatment is considered low-risk.
Blood Pressure Medications
Drugs to lower blood pressure may be prescribed for your pet, especially if high pressure is putting them at an increased risk of cardiac issues. Proper dosing is required to ensure the medication works properly and to reduce the risk of side effects.
Medication designed to flush fluids from the system may be prescribed in cases which the animal is experiencing severe abdominal bloating or fluid retention. This medication increases the risk of dehydration and heart issues, so your cat should be monitored while undergoing this type of treatment.
In many cases, AV is untreatable and will require lifelong changes to support your cat’s health. Changing your pet’s diet may be required to ensure proper liver function in the future. A low-sodium diet with smaller amounts of high-quality protein and added antioxidants is commonly recommended.
In severe cases, surgery may be required to repair the malformation and associated damage. It is possible that part of the liver may need to be removed. Surgical treatment is also often required for tumors or cancerous tissue. Surgery will generally require hospitalization and carries a moderate risk.
Recovery of Liver Fistula in Cats
For most cats with liver fistula, the prognosis is good, and management of the condition is all that will be required. This may include long-term dietary changes, regular doses of medications, plenty of fresh water, and regular monitoring of liver function. Be sure to change your cat’s diet gradually if dietary changes are recommended. Follow all of your veterinarian’s instructions, including proper dosing of any prescriptions and returning for any requested follow-up visits. If your pet’s symptoms return or worsen, seek medical attention immediately.