WCE 2017: Medical Dissolution Therapy for the Treatment of Uric Acid Nephrolithiasis

Vancouver, Canada (UroToday.com)  Dr. Knudsen, clinical urology attending from Ohio State University at the Wexner Medical Center, presented data establishing the efficacy of medical dissolution therapy for the treatment of uric acid nephrolithiasis. The Wexner Medical Center treats over 500 patients a year for kidney stones but had no concrete data on how well different treatments worked and whether there are more efficient strategies we have yet to explore. Kidney stones, or more specificially, Uric Acid kidney stones, have a variety of factors that lead to their growth and accumulation with the highest risk factors being a low urine pH and a high saturation of uric acid. One proposed method of treatment is dissolution therapy for uric acid stone patients via urinary alkalization. This combines the two supplements potassium citrate and Allopurinol. Potassium citrate works by attaching to calcium in the urine, preventing the formation of mineral crystals that lead to kidney stones. Allopurinol decreases the production of uric acid in the body, which also helps prevent kidney stones. Dr. Knudsen and his team aimed to identify characteristics of uric acid stone formers and determine the tolerability and efficacy of this medical dissolution therapy using the supplement potassium citrate. 

The study, a retrospective chart review, was comprised of 21 patients who were treated with potassium citrate and/or Allopurinol. Demographic data, aggregate stone size, time to stone clearance, urine pH, and complications were also analyzed to determine the scope of the study as well as derive what factors could relate to the individual responses of patients to the treatment. All patients were started on potassium citrate, while 70% of patients additionally supplemented with Allopurinol based on physician recommendation. The levels of both were also adjusted based on level of response to therapy. However, once the patients started responding to the potassium citrate, the supplementation of Allopurinol was discontinued. The patients were then split into 2 groups after the different levels of potassium citrate and Allopurinol were tested with the groups being complete responders (14) and partial responders (7). Complete responders had total dissolution of stones while partial responders decreased stone size an average of 68%. 

Dr. Knudsen concluded that medical dissolution therapy was well tolerated and is a great option of treatment for all patients. He also illustrated how his patients, on average, had over a 40 BMI. The fact that this therapy was so effective on typically tough, obese patients appeared quite promising to him and his team and warrants further supplemental studies on the efficacy on non-obese patients as well. While responding to a question from the audience about sodium bicarbonate supplementation as well, Dr. Knudsen explained how he was not testing the effectiveness of medical therapy of stones as a whole, but simply this singular supplement of potassium citrate. Though the study size was small, this study concretely substantiates this form of medical therapy as an option for the treatment of large stones.

Presented by: Dr. Bodo Knudsen

Authors: Bethany Gridley, Michael Sourial, Bodo Knudsen
Affiliation: Ohio State University, Wexner Medical Center, Columbus, OH

Written by: Vinay Cooper, Department of Urology, University of California – Irvine at 35th World Congress of Endourology – September 12-16, 2017, Vancouver, Canada