Giuliani spent a night in the hospital?

I have been under three times for surgery in the US and never spent a night in a US hospital. In a 6AM and out in the afternoon, stitches and grogginess be damned. The only time I can think of when anyone I know (besides a woman giving birth) spending a night in a hospital was my father, the night before he died.

American insurance companies are so against paying for overnight stays so I wonder what was going on with Giuliani. How bad did it have to be for him to receive such a privilege? If it wasn't serious, does this mean Giuliani supports change in health care, or only change for the select few like him? Maybe he just raked in a few million that he charged a poor Third World city and can afford cash. If only everyone else was so fortunate.

Or maybe Giuliani is REALLY sick and isn't telling anyone? (After the jump: Giulini's plane was diverted to an emergency room, yet his campaign won't say what's up - that's creepy.)
More from ABC's Jake Tapper:

Former New York Mayor Rudy Giuliani was all smiles for the cameras as he left Barnes Jewish Hospital in St. Louis Thursday afternoon after experiencing headache pains so severe he had his charter plane turn around on the way from Missouri to New York and was rushed to the emergency room.

"I feel fine," Giuliani said, refusing to answer any reporters' questions as he left the hospital....

The campaign shared no concrete medical information about which tests the mayor undertook and what the exact results were, also refraining from allowing the media to see his medical records or speak to his doctors.

And let's not forget that Giuliani had (has?) prostate cancer, which is quite treatable but also sometimes quite deadly.