ALT is a liver enzyme that increases in the blood stream when there is cellular damage. Bile acids is a liver function blood test. Bile acids can be increased in primary liver disease (secondary to liver dysfunction), microvascular dysplasia, and portosystemic shunt. A liver biopsy is recommended in dogs with chronically increased liver enzymes (especially ALT) for longer than 3 months and/or increased bile acids (after ruling out a portosystemic shunt, if warranted). Biopsies should be pursued even if the patient is asymptomatic or mildly asymptomatic. Obvious significant clinical signs will only typically occur when the patient goes into liver failure, which means that the patient has less than 10% of liver function left. Since a liver transplant is not an option in dogs or cats, the goal is to achieve a diagnosis and delay progression of the disease prior to the patient developing liver failure. 

 

Symptomatic treatment with nutraceuticals can be considered, but it is important to note that nutraceuticals will not prevent a dog with immune-mediated hepatitis or copper associated hepatitis from going into liver failure. 

 

An abdominal ultrasound can be performed to rule out a liver mass prior to the biopsy. 

 

Possible causes of increased ALT includes toxin ingestion (certain types of mushrooms, mold, and algae; some artificial sweeteners; some herbal remedies), reactions to some medications (Tylenol®, Rimadyl®), hepatitis (inflammation of the liver usually as a result of an autoimmune condition), abnormalities of copper metabolism, cancer, and infections (including leptospirosis, a bacterial infection acquired by drinking water infected with rodent urine) as well as benign changes like vacuolar hepatitis or regenerative nodules. Most of these conditions are treatable with medications. 

 

A liver biopsy is required to differentiate between these possibilities. There are 3 ways of obtaining liver biopsies, which includes conventional abdominal surgery, laparoscopic (video surgery), and via ultrasound guidance. Ultrasound guided liver biopsy is typically not recommended because the samples collected tend to be small and typically not representative of what is happening in the liver (as a whole). We recommend laparoscopic liver biopsy since it is less invasive. This procedure (like the others) requires general anesthesia and involves making two small incisions (the thickness of your pinky finger). The abdomen is inflated with CO2. A camera and a biopsy port are used for visualization and biopsy sample collection. This procedure allows the liver to be directly visualized and multiple samples from several different locations to be obtained, increasing the likelihood of reaching a diagnosis. Risks associated with the procedure include those associated with general anesthesia (prolonged recovery to death in rare cases), bleeding from the biopsy sites, premature opening of the sutures before the surgery sites are healed, and infection of the surgery sites. These complications are uncommon, and every precaution would be taken to ensure that the procedure is performed as safely as possible. The results of the biopsies are returned in 7-14 days. 

 

Overall prognosis will ultimately depend on the cause of the increased liver enzymes/bile acids as well as on the response to therapy.