I don't know how many here are fans of Maggie Drennon, formerly of Ceili's Muse, SixMileBridge and The Maggie Drennon Band.

She hasn't performed since 2004. I found a video posted by her on youtube, PMed her, and found out why. It's covered in detail on her MySpace page:

There was damage to my involuntary nervous system, and it’s called Autonomic Dysfunction. They figured out that my brain doesn’t adjust my blood pressure or heart rate anymore. There is most definitely no cure, and they experimented with a lot of meds before they could give it the right name, Postural Orthostatic Tachycardia Syndrome. The most unfortunate of acronyms, POTS.

The right medications finally helped me get up and around as of last April. I had been in bed for ten months, and it’s now been another ten months since I got out of bed. In living with it for almost a year now, it’s obvious that there are phases, a few weeks of feeling great, then a random relapse and lots of fainting and being stuck on the couch, then getting better for no reason. Some people compare it to MS in the way it affects your life. But the symptoms are way different.

I have a bucket load of meds and oxygen tanks and a wheelchair and federal disability income and the handicap parking sign and the whole schmere. I can’t walk too far or stand up very long. And most of all, I cannot ever ever take a deep breath. My breathing is shallow and small, any kind of breath control makes me pass out. Sometimes having a long conversation will do it. If I try to sing, I can get through maybe two lines of a verse and I’m screwed.
There's possible good news though:

It’s been overwhelming but I haven’t been depressed. I’m in the midst of accepting that I may not sing again, but I also have a fifty percent chance of recovering within five years.
Here's her whole MySpace blog

Youtube: The Maggie Drennon Band with Maggie singing "Willie Taylor" in 2002

Youtube: A short clip of Maggie with SixMileBridge; no date provided but I'd guess 1999 or so