What Are the Causes of High Alkaline Phosphatase in a Canine?

Alkaline phosphatase, or ALP, is an enzyme produced by the liver, bones, intestines, kidneys, blood cells, mammaries and placenta. The average canine levels of this enzyme vary depending upon the dog's age and individual circumstance with levels between 12 and 121 IU/L (International Units per liter) being considered average. Elevated canine ALP levels are almost always a cause for concern. Speak to your veterinarian to obtain a diagnosis and discuss treatment options for your dog.

  1. Disease

    • A number of diseases can cause high levels of alkaline phosphatase in canines. Hyperadrenocortism, also called Cushing's disease, is one of the most common causes of elevated ALP levels in canines and leads to severely increased levels of ALP in the blood. Dogs with Cushing's show levels up to 100 times greater than average. Liver disorders including hepatic lipidosis, cirrhosis, hepatitis, hepatic nodular hyperplasia, copper storage disease and hepatic neoplasia can all cause high ALP levels. Bile duct disorders including cholangiohepatitis, biliary neoplasia and choleocystitis can also cause an increase in levels. Gallstones, pancreatitis and hyperthyroidism can also cause rises in levels.

    Age and Life Stages

    • Dogs in certain life stages have naturally higher levels of alkaline phosphatase than average. Young pups or dogs that are still growing have higher levels of ALP naturally present in their systems and display levels between two and 10 times higher than adults. Pregnant bitches also display a clinical increase in ALP since ALP is produced by the placenta. Dogs recovering from a fracture or break exhibit high levels of the enzyme. The stress of the disease itself, whether elsewhere in the body or directly relating to the primary cause of high ALP levels, can cause a small increase in ALP levels -- up to three times the normal levels.

    Drugs

    • Some drugs can cause elevated alkaline phosphatase levels. Corticosteroids lead to a 10 to 100 fold increase in ALP levels depending upon the dose and how long they are used. Glucocorticoids are used to combat inflammation and suppress the immune system and are used to control diseases such as arthritis or Addison's disease where these symptoms are present. Anabolic steroids are sometimes used illegally to build muscle in sporting dogs. Both glucocorticoids and anabolic steroids are corticosteroids and contribute to high ALP levels in canines. Anti-convulsant drugs used to treat seizure disorders such as phenytoin, primadol and phenobarbital also cause a mild to moderate increase in canine ALP levels.

    Genetics

    • A disease called familial hyperphosphatemia is present in Siberian huskies and Scottish terriers. This disease causes permanently elevated levels of ALP. The disease causes the kidneys to re-absorb phosphate ions. The disease is usually considered benign unless other mitigating factors or diseases are present.