My son has DMD, one of the wide variety of muscular dystrophies. Elevated CK is an indication of a problem affecting the cell walls. The CK enzyme literally leaks out though the cell wall due to damage. Its not the problem - just an indicator of other problems so it may be MD but it may be something else.

I understand your worries and the initial stage until you know whats happening is probably the worst. I know its probably impossible to do but worrying about it isn't going to change much. Go on holiday and enjoy the summer - between going to the beach and spending his time visiting doctors I'm pretty sure which your son will pick.

The temptation to investigate is irresistable so: Look at clinical symptoms - what does he do, how does he walk, etc and compare that with the symptoms of know types of MD. There are lots of diseases out there which share symptoms so it may be another thing. If it is MD check out 'gowers movement', its a simple indication... and then go to the beach - you can't do anything else.

Ian