pimp question during surgery

This is another pimp question I was asked during the formalization of a right BKA in an anuric guy who had chronic renal failure and was on dialysis:

CR (chief resident): so have you noticed how in a bad shape his bones are? Why do you think that is?
me: (thinking: here we go again for pimping firing squad #2)...hmmm because he is malnourished....? becasue he ahs osteoprosis???
CR: yeah possibly but he is way too young to be this bad in shape with hsi bones...so what else?
me: err....
CR: ok...I know you have been standing for 3 hours holding this leg and blood is not getting to your brain but you know the answer...jsut think about his biggest problem....
me:...he is anuric...he has kidney disease....
CR: bingo... so what.... ?
me: hhmmmmm...(light) he has chronic renal failure and in peopel with chronic renal failure you have renal osteodystrophy, that is you have high phosphate and low serum calcium...with low serum calcium, your parathyroid glands are activated and start secreting PTH to increase serum clcium adn the way PTH does that is by taking the calcium away from the bone and dump it into the blood to compensate...that is why his bones are in such a bad condition and easy to break...


always think about your pt's biggest disease ...dont look for zebras first...people wont pimp you on zebras they will pimp on things you know but that you could not connect the dots together in the right time....or they will in such a way that will amke you confuse because you are just not use to be asked about this topic in this angle....