We are trying to figure out whats going on with my son. He's 9, and has a history of leg/muscle problems after illness. Its very acute, and only happens about once each summer. He gets a summer cold/stuffy nose virus- with a sore throat, always a sore throat ( but only has had strep 2x and this has happened 6+) and a fever. Even a slightly elevated temp- last week only 100- He seems better, then after a few days cannot stand one morning. Crying in pain. It hurts him behind his knees and at the calf muscle. ( He will sit on the couch, or crawl around, and say that only feels stiff) Last time his CK level was 1500 a few days after the episode. It came back down over the next few weeks.He walks awkwardly for weeks afterwards and is weak but then recovers fully. He has been rechecked in between and CK was good. Lots of other bloodwork done but everythings ok.
He has had episodes of muscle fatigue/cramping/pain playing ball on hot days and hiking in warm weather, too, but is a pretty active kid otherwise.
He now sees a neuro dr who is inclined to think it is a muscle enzyme disorder and has mentioned a muscle biopsy. She wants to be sure its indicated but says there are some muscle enzymes triggered by heat. She has recently rerun bloodwork and we are waiting for results. Last week he had strep, felt better, had leg stiffness, but it never developed into anything more :) She ran his blood on the "stiff" day and ck was normal.
This does not happen in the winter. He can get the same upper respiratory stuff and he's fine.
I am so worried for my boy. Thanks for your time.