Q. I am a 34-year-old male. At the end of August, 2002 I experience dull right flank pain and blood in my urine. An IVP was taken at a local hospital and I was told that it looked clean. Initially, it was thought that it was a stone. I was told that I may have passed something.

He needs to wait for the results of the retrograde x-ray to get more information. Could there actually be a stone in my mid right kidney when an IVP did not show anything? Do all stones show up on a plain x-ray and an IVP?

A. Kidney stones are a common condition thought to affect 10% of men and 5% of women over the course of a lifetime. A genetic factor is likely in many cases as many patients know of a family member who have had stones as well. The stones occur when one of several mineral substances becomes too concentrated in the urine and a stone develops.

Calcium is the cause about 75% of the time. The stone can be present in the kidney and eventually in the ureter, the tube connecting the kidney to the bladder. Common symptoms include pain, fever, and blood in the urine. Common tests include x-ray, IVP (injection of dye showing the kidneys and collecting tubes on an x-ray), renal ultrasound (a picture created by sing sound waves), retrograde x-ray as you describe, and CT or MRI images.

Calcium stones will usually show up on x-ray or CT scan, the IVP and ultrasound will show a blockage. Stones caused by substances other than calcium are harder to visualize and additional tests may be needed. The majority of stones are small enough to pass spontaneously, but additional measures are needed if this does not happen.

http://www.nlm.nih.gov/medlineplus/ency/article/000458.htm

http://www.niddk.nih.gov/health/kidney/pubs/stonadul/stonadul.htm

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