I am female, 41 years of age and healthy. I was diagnosed in 1988 with a birth defect of left kidney (ureter tube and main blood vessel were twisted together, obstructing blood flow.) My surgeon repaired it and the kidney had 90% function at that time. In 2003 I had repeated bladder infections and was diagnosed with an atrophic left kidney that had a kidney stone. I had lithotripsy and the stone passed. At that time I had 18% function of left kidney, right kidney was healthy. I have been well until Nov 2005 when I had three back to back bladder infections. I had an ultrasound of my kidneys and it showed the left one had atrophied more than a year ago but had no stones. The right one was fine. My urologist did say the left ureter was dialated. He metioned he believed the kidney was having a "hard time" draining urine, due to it's reduced capacity to function. I was put on low grade daily preventitive antiboitics for a month and then am to see him again. He mentioned if I don't have pain or lots of infections, we can leave the kidney alone as it slowly loses function, but if it continues to cause infections or pain, it may have to be surgically removed. I am just wondering what an enlarged ureter with no obstruction indicates? Does that mean that my left kidney is functioning so slowly the ureter is contracting more to pass urine and therefore enlarged? Is this a dangerous siuation for serious infection? Will it go back to it's normal size with antibiotic treatment? Can it burst? Any additional information I can recieve on this subject would be very appreciated. Thank You.