The next thing your pediatrician may do is a test on your child's blood. There is an enzyme in muscle cells called creatine phosphokinase (CPK). Everybody has it, it is necessary for muscular effort. If muscle cells get damaged, CPK is released into the blood: a swift kick to the rear will increase your CPK level some.
In a young DMDer, the CPK level is 10 to 20 times as high. When he gets older, the amount of enzyme goes down because there is less muscle to produce it, but it never gets down to normal levels.
A high CPK level shows that there is definitely something going on in the muscles. It does not show what specific disease you are dealing with. It is at this point that your family doctor will probably refer you to the MDA.
