Mixed Connective Tissue Disease & High CPK Levels


I was diagnosed with MCTD a little over a year and a half ago. Just recently during some routine blood work, my CPK levels came back substantially elevated (1492 to be exact). I’m concerned as to what this could be an indication of. My doctor has prescribed a daily 40mg dose of prednisone for the next two weeks at which point we will re-test my CPK levels. Could you please shed some light as to what this recent elevation in the CPK level could be caused from?


CPK is a muscle enzyme that is found inside muscle cells. If the muscle cells are damaged from any cause the CPK enzyme will be released into the blood and the CPK test becomes elevated. There are many causes of CPK elevation. During a heart attack, the heart muscle is damaged and a high CPK level is often used to diagnosis an acute heart attack in the emergency room. Trauma to the muscle such as heavy exercise or accidents can elevate CPK. Drugs such as the statin colesterol medications can damage muscle and elevate CPK.

In your case, inflammation in the muscle from the mixed connective tissue disease can cause the CPK to be elevated. Thus your doctor has put you on prednisone to see if this will help.

Alan Matsumoto, M.D.

About Alan Matsumoto, M.D.

Part-time Faculty, Division of Rheumatology
Johns Hopkins University