bleeding kidney cysts

My doctor sent me to a urologist to be evaluated for blood in my urine.  The urologist sent me for a ct scan and found that I have kidney cysts.  A couple are bleeding, he said and I am to come back in a year to see if they have gotten any bigger. My questions are:  What causes the cysts in the first place?  What causes them to bleed and what can be done to stop it and what can be done to help prevent any further development of more cysts.  I have 15-0 between my two kidneys I was told.  I have had orange urine for several months now and wonder how long will this go on?  

Any help would be appreciated.

Thanks.

Kenny