[The system seems to have mangled my last reply, let me try again.]
"Maybe I should try something else first?"
Sure, the bicarb, and the Ankle Brachial Index and cholesterol panel. They can also feel for pulses in the lower legs. But since you probably mean: to directly look at the muscle instead of having a biopsy? I don't know, besides possibly MRI.
Maybe your doc mostly wants to rule out something bad like a muscular dystrophy. If the biopsy is negative, you are back where you started. After all, most muscle biopsies are seemingly done to investigate problems with muscle activation, not with pain alone.
You do say, "Right now the pain after walking is more around the knee than the thigh and calf. But initially it was thigh and calf" - so maybe it's time to wait and see, if the muscle is indeed getting better.
Here's a vid showing a Muscle Biopsy:
What if we disregard the rhabdo? Here's a DDx for exertional leg pain:
Note 'arterial endofibrosis' which is blockage without plaque (not uncommon in cyclists); but that's unilateral and is not sudden onset.
Come to think of it, let's maybe change having the Ankle Brachial Index done after you exert and have the pain... AND ask them to do a blood draw from a leg vein then, too. The muscle state might be different then. How's that sound?
"people that after rhabdo have chronic pain situations that take a good long time to go away."
But then there is the fact that he had ~8 months symptom free after the rhabdo. That's why I was thinking that the current 10 mos. pain didn't result from the rhabdo, but that maybe both the rhabdo and the seeming claudication are from the same cause.
"...which isn't worth more than the words I type if you know what I mean"
No, no... not at all. To the contrary, thanks for going back and forth on this, SM. MH could use more of that kind of thing, in a respectful think-tank kind of way. So please do more :)
"But I am curious what exactly the biopsy will be of."
Since he mentioned myopathy, I'd guess it will be several cores taken from areas of the thighs that have the pain. 'Several' because they wouldn't want to miss by taking just one (just like with FNA), and 'thigh' because it would seem wrong to do the calf - which is more stressed afterward in plain walking.
Do you take a cholesterol lowering medication, Jmc2835? Were you dehydrated when the initial situation happened? I know there are a host of reasons for why someone would develop rhabdo but it is rare. And if there is an underlying reason for why you developed it (like diabetes or some other chronic issue), then you'd be more prone to it recurring. That is scary you got it and would wonder the source. Rhabdo can do permanent damage. I have read that it can recur (the bouts of pain) years after the onset. What are you getting a biopsy of?
Jmc, nothing quite fits and that's why the cause hasn't been found yet - so let's speculate: after a little reflection, and as a shot in the dark, I'd guess that it's vascular. Just maybe, artery blockages in the legs are causing present claudication *and* that also contributed to creating the mild rhabdo. Your docs maybe never considered peripheral arterial disease, because you are too young.
A simple initial test is to compare blood pressure in the ankles to the arms (Ankle Brachial Index). You can ask any doc to do that, or even do it yourself if you borrow a BP cuff.
"Premature peripheral arterial disease – difficult diagnosis in very early presentation"
I'd also guess that genetic myopathy is the least likely, especially since there's no weakness.
Btw, there is a known association between viral illness and rhabdo. Maybe that's somehow related to how you had the stomach bug kicking off this new period of recurrent leg pain.
"Rhabdomyolysis Secondary to Influenza A Infection: A Case Report and Review of the Literature"
Hi, Jmc, you can try:
(1) websearching for--> sequelae rhabdomyolysis
or --> chronic complications rhabdomyolysis
and maybe also throw in 'claudication' or 'revascularization' to try to find case studies
(2) I'd try taking bicarb before exercise or a long walk, just to see if acidic metabolites are involved
EMGs are usually useless. I was told that after suffering through one. Has anyone looked at your hips? Your lower back? That pain can radiate to your legs, and it will get worse if nothing is done about it.