I am 83 years old and in generally good health, but for the last 10 years I have been suffering from severe pain in the left kidney region. Despite numerous hospital investigations I have been told that my kidneys are working properly and that there is no evidence of stones, though during one investigation after a particularly severe episode some blood was found in my urine. My doctor has recently told me that the probable cause is a dilated kidney pelvis that has been there since birth. I have been prescribed ibuprofen which I take to counter the pain, which occurs at any time of the day or night almost daily. Is it wise to continue taking this medication so frequently, or is there anything else I can take?

Dr Fred Kavalier answers your health question:

You should feel reassured that the tests have not revealed any serious cause for your pain. Although no kidney stones have been found, it is still possible that you produce tiny "stones" even one the size of a large grain of sand can cause quite severe pain as it passes through the urinary system. X-rays and scans do not usually detect such small things. The blood that appeared in your urine makes me think this could be the cause. Ibuprofen is a good painkiller, but it can cause stomach bleeding in the elderly so it's better that you take it intermittently rather than regularly. It would be safer to take paracetamol, and you should also be drinking plenty of fluids.

Please mail your questions for Dr Fred to health@independent.co.uk. He regrets that he is unable to respond personally to questions.