May 2003: Case Study 1

NR, a 36-year-old man, presents to his physician complaining of acute abdominal pain. He is convinced that he has kidney stones once again. He describes the pain as excruciating, intermittent, right-sided, and radiating to his groin. The patient is diaphoretic and has difficulty sitting still.

The physician notes that NR?s previous stones were identified as calcium oxalate. The doctor orders an x-ray and ultrasound, which confirm that NR has kidney stones again. Because the stones are small, the physician prescribes oxy-codone with acetaminophen until the stones pass.

NR does not understand why he developed stones again. After his last episode, he promised himself that he would stay healthy. He has a very extensive exercise regimen and ingests excessive amounts of vitamins, particularly vitamin C.

Why would NR?s exercise program and vitamin intake make him a candidate for further stone formation?