This has also happened to my son. On 4 occassions (between the ages of 5 and he woke up in the morning unable to walk but able to get around on his knees. Like your son at the end of recovery he would walk on tip toe. Only on the last attack was a blood test done which revealed a CK of over 4000. There were worries of MD but a further blood test was repeated two weeks later and fortunately the CK had gone back to normal. We then saw numerous doctors and had a number of tests but never got an answer to the problem. A potassium deficiency was suggeste;, the last doctor we saw favoured the viral theory. The muscle biopsy was suggested if he had another attack as otherwise he is fit and healthy. He has not had an attack for 2 years but the last couple of weeks he has complained of leg aches, tiredness and headaches. The doctors did another blood test but CK was ok however I am still concerned. I hope your son is ok, and just wondered if the muscle biopsy revealed anything or if you have gained any more information on this condition? Many thanks.View Thread