Patients with Crohn's disease are at increased risk for symptomatic nephrolithiasis. Stones in these patients are most commonly composed of calcium oxalate monohydrate or mixed calcium-oxalate and calcium-phosphate. Precipitation of both minerals depends on urinary pH, calcium, phosphate and oxalate excretion. The present manuscript reports on two patients with Crohn's disease and bowel resection, in whom the onset of symptomatic urolithiasis occurred after repeated infusions of ferric carboxymaltose - a drug, which is known to cause hyperphosphaturia. The present study shows that ferric carboxymaltose-induced hyperphosphaturia can be associated with kidney stone formation and symptomatic urolithiasis, especially in patients treated with calcitriol. Calcitriol has been shown to mitigate ferric carboxymaltose-induced secondary hyperparathyroidism and hyperphosphaturia, but is known to increase urinary calcium excretion. Chemical analysis of recovered stones revealed that they were mixed calcium oxalate and phosphate stones. Ring-like deposition of iron detected by spatially resolved elemental analysis using laser ablation-inductively coupled plasma mass spectrometry, showed that the stones also contained iron. Based on our findings, we propose that patients with inflammatory bowel disease requiring intravenous iron therapy should be carefully monitored for the development of hypophosphatemia and urolithiasis. If hypophosphatemia occurs in such patients, calcitriol should be used with caution.
Bone reports. 2024 Mar 29*** epublish ***
Marlene Panzer, Eva Meindl, Benedikt Schaefer, Sonja Wagner, Bernhard Glodny, Gert Mayer, Andreas Pircher, Christoph Schwarz, Felix Beckmann, Clivia Hejny, Bastian Joachim-Mrosko, Juergen Konzett, Herbert Tilg, Isabel Heidegger, Myles Wolf, Ralf Weiskirchen, Heinz Zoller
Christian Doppler Laboratory for Iron and Phosphate Biology, Austria., Department of Internal Medicine I, Austria., Department of Radiology, Austria., Department of Medicine IV, Austria., Department of Internal Medicine V, Anichstrasse 35, 6020 Innsbruck, Austria., Department of Medicine 1, Pyhrn-Eisenwurzen Klinikum Steyr, Sierninger Str. 170, 4400 Steyr, Austria., Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany., Institute of Mineralogy and Petrography, Faculty of Geo- and Atmospheric Sciences, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria., Department of Urology, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria., Division of Nephrology, Department of Medicine, Duke University School of Medicine and Duke Clinical Research Institute, 40 Duke Medicine Cir Durham, NC 27710-4000, United States of America., Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital, Pauwelsstr. 30, 52074 Aachen, Germany.