Could you describe this collapsing in more detail?

I have spells of weakness that come on quite suddenly, which my neuros say is "unusual" for MG. I have normal MG symptoms as well--all my muscles get tired and weak if I use them too much. But I also have "spells" of weakness, where I go limp all over quite suddenly.

I've been on Imuran for two years, and my spells are now less intense and don't last as long, but before the Imuran, they were like this: I would feel myself getting weak (it feels a lot like when you're drinking alcohol and feeling a "buzz"). Just a few minutes after I noticed that feeling, I would collapse--not fall, exactly, but go down slowly to a squatting position because my legs just couldn't hold me up any more. Sometimes I would get so weak I'd end up lying on the floor, unable to get up. Sometimes if a spell hit me while I was sitting in a chair, I'd find it very hard to stay vertical at all. These spells would last about 45 minutes, and then I'd recover enough to get up and walk. There was a time when I was on the floor so regularly that once one of my kids just stepped over me and kept going.

Anyway, my knees sometimes buckle, so I'm very careful on the stairs. Whatever muscles keeps you vertical, and stop you from bowing forward from the waist, often buckle, and then I, well, I make a quick bow from the waist--I fall forward from the waist up, and then right myself. Looks funny, I'm sure.

I am double seronegative (they never found antibodies in my blood for AChR or MuSK). I wondered for a long time if I have something else instead MG. I wondered specifically if I have a channelopathy like hypokalemic periodic paralysis or hyperkalemic periodic paralysis, because these come in "spells." But the neurologist who diagnosed me says that my single fiber EMG (by which I diagnosed) is strongly consistent with MG and inconsistent with HKPP.

If you are having trouble getting a diagnosis, I assume you've already tested negative for the blood tests--AChR, MuSK and LEMS. The next step would be to find a neurologist who specializes in neuromuscular diseases and who can give you a single fiber EMG (SFEMG).

Abby