Study on Concretions Developed around Urinary Catheters and Mechanisms of Renal Calculi DevelopmentGrases F. · Söhnel O. · Costa-Bauzá A. · Ramis M. · Wang Z.
aLaboratory of Renal Lithiasis Research, Faculty of Sciences, University Illes Balears, Palma de Mallorca, Spain; bUniversity of J.E. Purkyne, Ústí nad Labem, Czech Republic, and cDepartment of Physical Chemistry, University of Leoben, Austria
Aims: To study the structure and composition of encrustation and concretions developed on urinary catheters to better understand their formation mechanism to be able to prevent them. Methods: The surface of catheters was studied by direct and scanning electron microscopy observation. In vitro formation of encrustations was performed in synthetic urine. Results: The surface of catheters was covered by a continuous layer of organic matter, on which a thin scale consisting of crystals of calcium oxalate monohydrate (COM), uric acid anhydrous or calcium phosphate developed. Encrustations observed on catheters generally exhibited the same composition as the previously developed renal calculi. In catheters collected from patients without previous episodes of renal calculi or with previous episodes of infected renal calculi in which infection was afterwards eradicated, on the first organic layer, in that case plate-like COM crystals forming a columnar layer were observed. In vitro experiments demonstrated that COM columnar structures were only formed when normocalciuric urine containing organic matter was used, and the presence of crystallization inhibitors, as phytate, notably delayed their formation. Conclusion: Calcium oxalate was the main crystalline phase developed on catheters inserted in patients, specially in the absence of urinary infection or urinary pH values <5.5 and high urinary uric acid levels. Thus, prophylaxis of encrustations may consist of preventive measures usually applied in cases of recurrent idiopathic calcium oxalate urolithiasis.
Prof. Dr. F. Grases
Laboratory of Renal Lithiasis Research, Faculty of Sciences
University of Illes Balears, Ctra. Valldemossa Km 7,5
E–07071 Palma de Mallorca (Spain)
Tel. +34 971 17 32 57, Fax +34 971 17 34 26, E-Mail firstname.lastname@example.org
Received: Accepted: August 7, 2000
Number of Print Pages : 9
Number of Figures : 12, Number of Tables : 1, Number of References : 30
Founded 1964 by G. Richet and G.E. Schreiner
Vol. 88, No. 4, Year 2001 (Cover Date: August 2001)
Journal Editor: G.M. Berlyne, Brooklyn, N.Y./Beersheva; S. Ito, Sendai
ISSN: 0028–2766 (print), 1423–0186 (Online)
For additional information: http://www.karger.com/journals/nef