Elevated Liver Enzymes in Dogs

A dog's liver is a multi-tasking organ that metabolizes fats, proteins, and carbohydrates in the body. It plays an important role in blood clotting, toxin filtering, and waste removal. It also stores fat-soluble vitamins A, D, E and K, and secretes bile which is vital for proper fat metabolism. Therefore, if the liver gets damaged, the dog's body won't detoxify the various metabolic waste and by products. The liver secretes specific enzymes for performing these tasks, and one of the main determinants of liver function is to measure the systemic levels of these dog liver enzymes. When the liver is malfunctioning, these canine liver enzyme levels often get elevated, and if the level of secretion goes beyond the normal level, the dog may suffer from various health related problems.

ALT (alanine aminotransferase) or SGPT (serum glutamic pyruvic transaminase) is a liver specific enzyme, secreted when localized liver cells die due to an infection or interruption of blood supply. Under abnormal conditions, the serum levels may go up by four to five times the normal level, and can cause non-hepatic disorders like inflammation of the gastrointestinal tract, hemolytic anemia, and heart failure. A dog undergoing treatment with anticonvulsants and glucosteroids can show this significant increase in the ATL levels. Similarly, AST (aspartate aminotransferase) or SGOT (serum glutamic oxaloacetic transaminase) is another liver enzyme which is detected in muscle tissue and red blood cells. An increase in levels of AST can also cause liver disorders more severe than ALT. Elevated liver enzymes like GGT (gamma-glutamyl transpeptidase) and SAP (serum alkaline phosphatase) can signify liver disease due to obstruction of bile ducts.

What is a Normal Reading for Canine Liver Enzymes?
When a veterinarian runs a blood panel on a dog, he generally checks for five enzymes. These five enzymes are very important in diagnosing, liver disease in dogs, if any. These enzymes include alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALKP), serum bilirubin and gamma glutamyltransferase (GGT). The normal liver enzyme in dogs according to Merck Veterinary Manual is as follows:

• Alanine Aminotransferase: 8.2 to 57 u/L
• Alkaline Phosphatase: 10.6 to 101 u/L
• Aspartate Aminotransferase: 8.2 to 57 u/L
• Gamma Glutamyltransferase: 1.0 to 9.7 u/L
• Serum Bilirubin: 0.1 to 0.6 mg/dL

Causes of Elevated Liver Enzymes in Dogs
The following are some of the most common causes of elevated liver enzymes in dogs:

• Jaundice:
  Jaundice, being one of the cause, usually occurs when the liver is incapable of removing bilirubin, a waste product generated from the breakdown of hemoglobin. It gets accumulated and causes a yellow color formation around the whites of the dog eyes or the pale areas of the gums.
• Pancreatitis:
  Pancreatitis, or blockage in the bile duct, causes raised levels of the GGT enzyme in the liver, which gets concentrated in the kidneys and pancreas.
• Cushing's Disease:
  Cushing's disease causes an excessive generation of adrenal hormones, specifically corticosteroids. As a result, there is an increase in alkaline phosphatase in the liver which imbalances the salt levels.
• Infectious Hepatitis:
  Infectious herpes gets transferred from one dog to another through contact or ingestion. Along with herpes, the parasites may attack the liver and increase the amount of liver enzymes to remove the assailants.
• Metabolic Diseases:
  Metabolic diseases like cobber accumulation, deposition of fat in the liver due to obesity, diabetes, and hypothyroidism in dogs can also lead to high liver enzymes in dogs.
• Medications:
  Medicines like corticosteroids or epilepsy medicine can also raise the enzyme levels in the liver.
• Other Factors:
  Congenital diseases like hepatic shunts, congestive heart attacks, liver cancer, etc. are some other causes for elevated liver enzymes in dogs.

Symptoms of Elevated Liver Enzymes in Dogs
Symptoms of liver disease due to elevated liver enzymes in dogs are hard to pin-point as they are subtle, vague, and often similar to those relating to other dog illnesses or diseases. Following are some common symptoms observed in dogs suffering from this condition:

• Diarrhea and vomiting
• Constipation
• Lethargy and depression
• Bleeding disorders
• Accumulation of fluids in the abdominal cavity
• Anorexia or loss of appetite
• Pale gray stools
• Weight loss and anemia

Treatment for Elevated Liver Enzymes in Dogs
The best course of treatment primarily depends on the degree of the liver enzyme elevation, which determines how sick the dog is. Therefore, the first step is to address the cause of the dysfunction. This may include the use of antibiotics if there is an infection, or supportive care for toxins. The sick dog may be put on the medication Denosyl, which helps in promoting liver health. The dog's diet or dog food, should be low in fat and protein, as this will minimize the liver's workload to metabolize the food. Limited sodium intake is another way to reduce the elevated enzyme level as it prevents high levels of ammonia during digestion.

Elevated liver enzymes in dogs is a serious dog health issue that should be taken care of under veterinarian care and supervision. Liver enzyme levels two to three times more than the normal level is usually considered as insignificant, but levels beyond this need immediate doctor's attention.