Hello,
I normally live on the myasthenia gravis forum, but wanted to post a question here.

Two neurologists that I've seen have suspected myasthenia (MG), but my second neuro / current one says he also wants to give consideration to metabolic myopathy.

He's a neuro who specializes neuromuscular diseases, so I'm sure he's more than qualified in examining for it.

Primary symptoms are legs and arms weakness, difficulty walking, cramping after muscle use, and blurred vision. Previously healthy and athletic, primarily bodybuilding and running.

Is that a term for mitochondrial disease?

This is what Medscape says:
http://emedicine.medscape.com/article/1173338-overview

In my travels, on line, these specialists are not common, and
mostly associated with large teaching hospital complexes.
I believe they are neuromuscular and/or genetic specialists.