(UroToday.com) Naim Maalouf took the stage and delivered a riveting talk regarding various endocrine factors in the etiology of stone disease. He placed the formation and propagation of the two most common stones, calcium oxalate, and uric acid, in the context of factors related to acquired defects of metabolism, diet, and genetics.
Dr. Maalouf stressed the relationship between uric acid stone disease and the independent risk factors of type 2 diabetes mellitus (T2DM), the most common endocrine derangement seen in stone disease, as well as obesity. In addition to explaining the mechanisms of increased urine pH and decreased urine ammonia, Dr. Maalouf described a study of a potential treatment for these patients. Pioglitazone, an insulin sensitizer, compared to placebo at 24 weeks, resulted in an increase in urine pH and increase in ammonia compared to control.
Next, Dr. Maalouf then went on to discuss calcium oxalate (CaOx), which is related to the concentration of both calcium and oxalate in the urine. Dr. Maalouf showed that urine oxalate is related to increased BMI. Additional dietary factors included increased sodium, protein, and oxalate consumption. Beyond oxalate consumption, absorption could be enhanced, possibly due to gastrointestinal inflammatory diseases, or endogenous production could be increased, possibly related to fatty liver disease.
Dr. Maalouf also touched on primary hyperparathyroidism, which is related to CaOx stones through increased urinary calcium from bone resorption and gut absorption. Stones are the most common symptom in these patients and urologists are encouraged to screen for this disease. Endocrine factors appear to normalize after parathyroidectomy and stone rates decrease but, importantly, stone rates do not go to zero so the urologist must remain vigilant. Finally, Dr. Maalouf reviewed various genetic defects that lead to the decreased breakdown of hydroxylated vitamin D as well as diseases such as sarcoidosis and malignancies leading to increased urine calcium and CaOx stone disease. Further details can be found by viewing the on-demand video of this session.
Presented by: Naim Maalouf, Endowed Frederic C. Bartter Professor in Vitamin D Research, Director of the Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas, Southwestern Medical Center, Dallas, TX
Written by: Zachary Tano, MD, Endourology Fellow, Department of Urology, University of California Irvine, during the 2024 American Urological Association (AUA) Annual Meeting, May 3 – May 6, 2024, San Antonio, Texas