Hi, Anne. Welcome!

Um, I have to tell you that you don't have a "slight" B12 deficiency. Every cell in your body is now running on fumes, if it's getting any B12 at all. It's dangerous! I'll bet your homocysteine and/or methylmalonic acid are high. Did anyone check your parietal cell or intrinsic factor antibodies (looking for pernicious anemia)? There's always a CAUSE for a B12 deficiency!

What kind of B12 are you taking? Methylcobalamin is the superior form. Cyanocobalamin has to be converted by the liver into methyl before the body can use it and your body needs it right now! Take at least two 5 mg. tablets twice a day. I personally like the Jarrow brand, but there are other good brands. I get mine on Amazon (cheaper).

Your doctor is misinformed. The blood test checks what is circulating in the bloodstream and not what is actually getting to the tissues. Oy. Most people take B12 the rest of their life after a deficiency. I do, since I was diagnosed in 1999.

What about vitamin D? Did they check that very common deficiency, too?

Your symptoms sound a lot like MG. MG is all about fatigable weakness, which is what you describe. If you have had MG that long, Mestinon might only sort of work right now. You could be so bad off that the only things that will show dramatic improvement are steroids or some other treatment such as IVIG. The worse a person gets with MG, the more help they need. And Mestinon is only a helper drug, and doesn't address the underlying autoimmune process.

There are muscles that open and shut the eyelids, so if the muscles that close them aren't working, they won't close! More often it's the other way around, but it does happen.

Tinnitus could be an effect of MG (muscles are in the ear, too) or the B12 deficiency. Or something else such as allergies.

A person with MG can become weaker so slowly that they don't realize how weak they are until they do an activity. What you describe, such as the arms trembling, sounds so much like MG. MG can trick you into thinking you're okay, and then can slam you into the ground the next day. It's highly unpredictable and you have to take it easy!

Does being out in the heat make you worse? It will make MGers much worse.

Are you at all short of breath? Seeing a pulmonologist is a very good thing to do for MG. At the very least, you can get a baseline of MIP and MEP breathing tests.

If you get to the point where you can't swallow, breathe well (in or out), or move well, you need to dial 911. MG can tank really quickly and you can't know how bad it will get. So please stop ignoring your symptoms and take it seriously. We've all done that, but since you aren't on more than Mestinon and aren't doing well, you can't really take that kind of risk with your life.

MG is called a "head and down" disease, because people will often notice any eyelid drooping or head/neck muscles weakness first.

Did that one doctor give you proof of a 6th cranial nerve issue? That still wouldn't cause fatigable weakness.

What else can we help with?

I hope you get answers soon. It's not exactly fun having MG, but, if you do, there are ways to treat it and live a good life with it!

Annie