Why is it not worth a shot to ask? I wouldn't necessarily ask for medical advice nor follow it, but there'd be that small chance someone else would know something worth pursuing with my doctor (like what seems to have happened in this topic).
For about 6 months on end this past year I had a laundry list of respiratory issues that several different doctors I went to couldn't figure out the root cause of. All anyone could do was to deal with the symptoms, try to come up with some kind of diagnosis, and hope that it'll fix whatever was going on. I was on at least half a dozen different meds ranging from a monthlong course of Levaquin to prednisone and nasal sprays and more at any given time, and of course none of that stuff would do anything about a nasty, persistent cough that would never go away (great timing with the H1N1 scare!).
So after too many xrays and ct scans and blood tests and blowing into things and who knows what more, I was really fed up. I had been to all sorts of specialists, general practice, even my dentist (sinusitis at some point, had to rule out anything to do with my teeth), and everyone was out of ideas. It was wrecking my relationships with some clients who thought I was giving them the flu, it was preventing me from even climbing up a flight of stairs on a bad day, the cough was bad enough that I'd wake up multiple times during the night, everyone and their mother thought I had a cold or the flu or $deity forbid H1N1... I was on the verge of crying when I was waiting for a flight at an airport when some woman that had sat down next to me decided standing up and away from me was preferable to being next to me coughing into my elbow away from her. And I didn't have anything contagious at that point. :/
I bounced ideas off some friends, I ranted on twitter and irc, went to one of the doctors suggested by someone I knew, and after mixing that all together, a specific combination of a few meds solved every problem I had. A little ridiculous to think about in the end, but my limited crowdsourcing worked for me. Even with the complete lack of domain-specific knowledge, it was a bunch of fresh pairs of eyes thinking things in their own way as I and all my then-doctors had started to become one with "we have no idea what's going on".
However, had any of my doctors pulled a House and ditched some choice assumptions about what happened with "99% of [their] patients" that had any one of my issues or "what happened in [my] medical history", I probably would have been much better off earlier. But I eventually (mini-crowdsourced and) met my House that assumed my medical history is tantamount to a lie and started with a blank slate. What everyone had assumed was the effect was a cause, where it was assumed something would work because it worked in the past was proven to be wrong, and now I'm here, minus most of the problems I had back then and managing the problems I can manage, happy and reasonably healthy today :)