Inflammation and spontaneous stone expulsion rate


I would like to congratulate Aldaqadossi [1] on his study of the role of plasma C-reactive protein (CRP) in predicting stone expulsion. In this elegant work, the above author concludes that patients with high CRP levels seem to have little probability of spontaneous expulsion, suggesting a role played by inflammation on the failure of medical therapy (a-blockers) to expel ureteral stones. Nevertheless, in my opinion, this study has some limitations. Although the methods and the inclusion and exclusion criteria are rigorous, the choice to subject patients who fail to expel stones within 4 weeks to ureteroscopy does not seem to be in line with evidence-based indications. Considering data reported in the literature and also cited in the European Association of Urology Guidelines on Urolithiasis, it takes 39 days for 95 % stones of 4 and 6 mm to be passed [2]. The definition of failure proposed by Aldaqadossi may be erroneous in considering a period of only 28 days and the consequent decision to subject patients who fail to expel the stone within this limited period to endoscopy may conceal the true spontaneous expulsion rate. However, focusing on the possible role of inflammation on decreased stone expulsion rate, perhaps Aldaqadossi should also have studied serum white blood cell (WBC) and neutrophil counts. Recent experience has shown the role of increased WBC count in predicting spontaneous expulsion, suggesting that stones incapable of moving forward in the ureter may produce minimal inflammation during renal colic, or a less significant reaction than that produced by a stone which is moving down the ureter and producing an inflammatory reaction along it [3]. These additional data could provide interesting indications on the usefulness of anti-inflammatory drugs, such as corticosteroids, in expulsive medical treatment. Corticosteroids inhibit the transcriptional activity of several genes encoding for proinflammatory proteins, including phospholipase A2 and cyclooxygenase 2, both of which are important for prostaglandin synthesis. Researchers have reported controversial data on the effects of prostaglandins on ureter contractility. Dellabella et al. [4] evaluated the additional benefit of corticosteroids with tamsulosin to treat distal stones, and reported a reduced expulsion time. In a similar study, Porpiglia et al. [5] found that corticosteroids were only effective when administered together with a-blockers. As our understanding of the role of inflammation in urolithiasis is not yet entirely clear, analysing various inflammatory markers does not only clarify the correlation between inflammation and stone expulsion, but may also contribute to identifying some biochemical parameters increasingly more capable of predicting spontaneous stone expulsion rates, thus allowing earlier treatment of patients with a high probability of failure of expulsive medical therapy.

DOI: 10.1007/s00240-013-0569-4

Cite this paper

@article{Moro2013InflammationAS, title={Inflammation and spontaneous stone expulsion rate}, author={Fabrizio Dal Moro and Filiberto Zattoni}, journal={Urolithiasis}, year={2013}, volume={41}, pages={363-364} }