Intradermal sterile water injection for acute renal colic pain

In this letter, we would like to comment on the study entitled “Intradermal sterile water injection versus diclofenac sodium in acute renal colic pain: A randomized controlled trial.” [ ]. The established data related to subcutaneous distilled water injection in renal colic pain condition have been presented during the European Association of Urology Congress, which was held in Istanbul, Turkey in 2005 [ ]. Besides, we have published a retrospective study paper on this method, which we have been applying for about 15 years [ ]. We prefer to use the method firstly introduced by Martensson et al. [ ]. In this approach, four distinct sites are determined for injection-induced papule formation instead of one site. The superior aspect of the method by Martensson et al. is that the renal colic pain is effectively blocked in a way that has been described in Melzack theory. According to this theory, consecutive injections increase the pain threshold, which in turn competitively block and mask the current renal colic pain carried by the afferent sensory neuronal pathway to the brain. Especially, this effect is more prominent after the formation of temporal summation following the third and fourth papule formations (Photo). This injection-induced pain feeling is so terrible so that, even some patients with renal colic refuse to receive this treatment again in case of a recurrency [ ].