PURPOSE: To evaluate the possible effects of citrate replacement on the efficacy of shockwave lithotripsy (SWL) in the management of kidney stones in cases with hypocitraturia.
METHODS: Forty hypocitraturic cases with renal pelvic stones were randomized into two groups; while citrate replacement has been done before and at the time of SWL in Study Group I (n: 20), SWL was performed without any additional specific management for hypocitraturia in Study Group II (n: 20). Twenty normocitraturic cases were also chosen as the control group (Group III). Data of the patients were evaluated comparatively.
RESULTS: Patient, stone, and urinary pH characteristics of the groups were similar. Pre-SWL urinary citrate levels were 0.71 (0.1-1.3), 0.86 (0.1-1.4), and 3.12 (1.8-4.4) mmol/24 h in Group I, II, and III, respectively. Urinary citrate value increased from 0.71 (0.1-1.3) to 1.96 (1.6-4.1) mmol/24 h following replacement therapy (before and at the time of SWL) in Group I. Mean number of SW (p = 0.461), rate of stone-street formation (p = 0.146), and Double-J placement (p = 0.291) were similar in Group I and Group II. While the mean number of SWL sessions (2.27 ± 0.71 in Group I vs. 2.94 ± 0.59 in Group II; p = 0.027), and time to stone-free status [29.1 (16-47) days in Group I vs. 38.4(21-63) days in Group II; p = 0.043], was significantly different between study groups, these parameters were found similar between Group I and Group III.
CONCLUSIONS: In our study, the patients with hypocitraturia, who did receive replacement therapy, tended to require lower number of SWL sessions and became stone free in a shorter period than the others who underwent SWL without any specific management of hypocitraturia.
Int Urol Nephrol. 2012 Oct;44(5):1357-62. doi: 10.1007/s11255-012-0190-4. Epub 2012 May 12
PMID: 22581424 [PubMed - as supplied by publisher]
The total duration of the citrate replacement is not given. The stone fragments were analysed but the stone analysis is lacking. The number of ESWL sessions seems to be high
Group I Group II Group III
Stone size (mm) 12.5 ± 2.1 13.2 ± 3.4 14.4 ± 2.7
Urinary pH : 5.28 (5–5.5) 5.33 (5–5.5) 5.4 (5–6)
Success rates (stone-free status)
1. Session 2/20 1/20 1/20
2. Session 6/20 4/20 4/20
3. Session 18/20 16/20 15/20
4. Session (re-SWL) 19/20 18/20 18/20
It is difficult to imagine how citrate should be working. The authors quote a publication that "has shown that micro-hardness and fragility of calciumoxalate monohydrate and phosphate stones can be significantly influenced by the pH values of their fluid environments." In the present study the urinary pH was not significantly different in the 3 groups. In the paper quoted, the hardness of whewellite stones was only changed in stones exposed 12 hours to a pH of 9.5