Good day! Fistula between the colon and any part of the urinary system would almost always present with recurrent urinary tract infection and sometimes passage of air in the urine termed pneumaturia . Have you been having on and off urinary tract infection for 8 months now or just one episode of UTI? You may need to get a urine sample examined to see if there sediments that might point to a possible fistula. Imaging studies to check for fistula are not always sensitive and clinical history still prevails and a high degree of suspicion. I also think you need to divulge your past history of fistula to your new MD so t he/she will have a clearer picture of what you might have. Blood iron levels are a good parameter to check on your nutritional status. Are you eating well? Do you have loss of appetite or losing weight? Again these are aspects that you need to discuss with your MD. I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications at: http://www.HealthcareMagic.com/doctors/dr-manuel-c-see-iv/66014 I would gladly help you. Best wishes.