"As far as I can tell, the hospital appears to be unrelated to bikes, and it should not keep me off a bike." Well, I can no longer confidently say that the bike was unrelated to the hospital and, while it won't keep me off a bike, it may well change the way and some places I ride. For example, I'm thinking Cyclocross might not be a brilliant move this year.
I didn't go into details because, at the time, it wasn't exactly clear WHAT was wrong with me. Since then, the doctors all agree with each other that I had a Pulmonary Embolism (PE), likely caused by Deep Vein Thrombosis (DVT) coming from my right leg. I probably delayed the diagnosis because I told them I rode pretty much every day, whereas the condition is more often associated with airline passengers in economy class, truck drivers, bedridden people, and others whose legs must stay in one place for long periods. While I do work as an engineer in an office, I think few would characterize me as deskbound. They agreed it "didn't fit the pattern." Well, doctors may know a lot about medicine but mostly they don't know much about bike commuting in North Texas.
Because it does fit the pattern. As it turns out, Pro Cyclist Frank Vandenbroucke, aged 34, died of PE just last year. Tom Zirbel suffered a nonfatal PE in 2007. And there are others. What's more, this is a problem that is misdiagnosed and missed frequently. How can this be? As it turns out, it makes more sense than you might imagine, and, as a cyclist, there are very simple steps you can take to reduce your vulnerability to this.
For now, I just got home after five days in the hospital, so I'll go into details as to how it occurs and the simple things you can do to help in another post. So as not to keep you hanging, if you want some of the details ahead of time, here is probably the best source I've found. In the meantime, keep well hydrated!