One sided weakness? MG

Has anyone with MG experienced persistent, one-sided arm/tricep weakness like this?

About three years ago, I suffered a pretty serious injury to my left pinky on my dominant hand. I cut it open, damaged a nerve, and eventually needed surgery to repair it. I was in a cast for months, followed by a splint for several more months. During that time, I couldn’t properly use my dominant arm, work out, or train the way I had for years.

Once the splint came off, I tried to slowly get back into lifting. At first, I assumed the extreme weakness was just muscle loss, fatigue, and gym rust. I have over 10 years of lifting and fitness experience, so I figured muscle memory would eventually kick in and, within time, my strength would start coming back.

It didn’t.

I noticed significant strength loss in my left arm, particularly my tricep. I couldn’t seem to get a proper contraction or blood flow/pump in the muscle. My right arm responded normally, while my left arm fatigued quickly, felt unstable, and sometimes seemed like it just wanted to give out.

Not long after this started, I developed a droopy left eyelid, followed by double vision. I initially thought it was ptosis, but my eye doctor eventually sent me to the hospital. I was admitted for five days and underwent multiple tests, including a spinal tap, because they initially believed I may have had a stroke.

I was eventually referred to a neuro-ophthalmologist and diagnosed with myasthenia gravis. I was prescribed Mestinon and prednisone, which I took for several months before stopping because of the side effects. My double vision and droopy eyelid resolved and, thankfully, have not returned to this day.

This is where my confusion comes in.

From what I’ve read about MG and from other people’s experiences, many of the common symptoms don’t feel persistent or noticeable in my everyday life. I don’t feel like I’ve completely lost my strength or energy. The main issue I continue to deal with is significant weakness in my left arm—particularly my tricep—and it has barely improved over several years.

My right arm is much more responsive and stable. My left arm sometimes twitches, fatigues much faster, and certain movements feel noticeably less controlled. Pushing movements are the biggest struggle. Push-ups, pressing movements, and anything requiring significant tricep strength are extremely difficult. Pull-ups are also a struggle.

Even with something like a bicep curl, my right side feels stable and strong. After a few reps on my left, I may find myself jerking or using my body to get the weight up because the arm simply doesn’t feel supported or stable anymore.

I’ve seen two different physical therapists. The first initially helped me regain strength and function in my pinky before we began addressing the larger strength issue. The second PT also worked with me on the weakness and used electrical stimulation on the affected areas. I could physically feel the stimulation, but even then I couldn’t fully extend my arm against resistance. We spent weeks doing exercises and testing movements to gauge improvement, but there was very little progress.

My second PT suggested the weakness could be related to MG. For a long time, I didn’t want to believe that.

The hardest part mentally is that I wasn’t new to fitness when this happened. I had trained for more than 10 years. I understood my body, had built significant strength, and had just decided to commit to fitness professionally and prepare for my first competition.

Then suddenly, basic movements I had done for years became a struggle.

It’s a very strange feeling when your mind knows exactly how to perform a movement, you know what muscle you’re trying to contract, and you remember what the movement is supposed to feel like—but your body simply won’t respond the same way.

A part of me keeps wanting to believe this is severe deconditioning or a strength imbalance that I can eventually work through. But after several years with little to no improvement, I’m starting to question that.

I’m currently not taking MG medication. My previous ocular symptoms have remained gone, and I don’t experience many obvious or alarming MG symptoms in my daily life. The persistent weakness is mainly concentrated in my left arm and tricep, which is also why I’ve always found it strange.

Has anyone with MG experienced something similar—persistent weakness primarily affecting one limb or one muscle group for years?

Could this still be MG-related even without my previous eye symptoms returning? Has anyone dealt with a combination of MG, muscle atrophy from prolonged immobilization, or a possible nerve/neuromuscular issue that presented like this?

I’m not looking for a diagnosis from the internet. I’m mainly trying to figure out what direction I should be looking in and what type of specialist or testing I should be asking about next.

Any experiences, advice, or direction would be greatly appreciated. Thank you in advance.