The analysis of influence of urine pH and diuresis on urine saturation with lithogenic compounds when justifying urolithiasis prevention in military personnel

Biochemical parameters of 24-hour urine from 235 military patients with urolithiasis were analyzed to determine the concentration and excretion of lithogenic substances, lithogenesis inhibitors and complexing agents. 24-hour urine pH and volume were assessed as well. Degrees of urine saturation with major lithogenic compounds were assessed, sequences of their deposition were identified as well as crystallization-initiating compounds. When urine pH increased (7.0 to 4.5), the saturation of urine with uric acid changed from values corresponding to unsaturated state (pH over 5.8) to critical supersaturation levels (pH less than 5.2). When pH decreased, urine saturation with phosphates increased more rapidly than urine saturation with uric acid under increased pH. Urine supersaturation with hydroxyapatite above the metastable zone is observed at pH greater than 6.1. The average pH for urine precipitation is (6.06 ± 0.89), whereas the average optimum pH value is (5.67 ± 0.19). Optimization of urine pH can reduce the risk of stones by 63 % (2.7 times) related to phosphate lithogenic compounds and uric acid. In 37 % of patients there is a risk of spontaneous nucleation of calcium oxalate, ammonium and sodium urates. An additional increase in urine output within the optimal pH range up to 1.8–2.0 liters of urine (1.4–1.5 times the original) virtually eliminates potential for nucleation of ammonium and sodium urates. After optimization of the urine acidity and an increase in diuresis, supersaturation with test compound higher than metastable level persists in 5.1 % of patients, including supersaturation with calcium oxalates, ammonium urates and sodium urates in 3.9 %, 0.8 % and 0.4 % of patients, respectively.

1. Alyaev Yu.G., Kuz’micheva G.M., Kolesnikova M.O. [et al.]. Klinicheskoe znachenie fiziko-khimicheskogo issledovaniya sostava mochevykh kamnei i mochi [Clinical significance of physico-chemical evaluation of composition of urine stones and urine]. Urologiya [Urology]. 2009. N 1. Pp. 8–12. (In Russ.)

2. Garilevich B.A. Obosnovanie i razrabotka sistemy primeneniya fizicheskikh faktorov v tselyakh lecheniya i reabilitatsii lits opasnykh professii s mochekamennoi bolezn’yu (kliniko-eksperimental’noe issledovanie) [Rationale and design of system of physical factors for the treatment and rehabilitation of patients with urolithiasis engaged in hazardous occupations] : Abstract dissertation Dr. Med. Sci.. Moskva. 2005. 46 p. (In Russ.)

3. Golovanova O.A. Patogennye mineraly v organizme cheloveka [The pathogenic lithogenic compounds in humans]. Omsk. 2006. 400 p. (In Russ.)

4. Levkovskii S.N. Mochekamennaya bolezn’: prognozirovanie techeniya i metafilaktika [Urolithiasis: prediction and metaphylaxis]. Sankt-Peterburg. 2010. 120 p. (In Russ.)

5. Paronnikov M.V., Protoshchak V.V., Levkovskii S.N. Metafilaktika mochekamennoi bolezni v Sankt-Peterburge (opyt dvukhletnego nablyudeniya) [The metaphylaxis of urolithiasis (2-year follow-up)]. Aktual’nye voprosy urologii i ginekologii [Topical questions of urology and gynecology]: Scientific Conf. Proceedings. Sankt-Peterburg. 2010. Pp. 31-33. (In Russ.)

6. Chiglintsev A.Yu. Struktura, mineral’nyi i khimicheskii sostav mochevykh kamnei [Structure, mineral and chemical composition of urine stones]. Chelyabinsk. 2010. 160 p. (In Russ.)

7. Ushakov I.B. Ekologiya cheloveka opasnykh professii [Ecology of humans engaged in hazardous occupations]. Moskva : Voronezh. 2000. 128 p. (In Russ.)

8. Kavanagh J.P. Supersaturation and renal precipitation: the key to stone formation? Urol. Res. 2006. Vol. 34. Pp. 81–85.

9. Pak C.Y.C., Rodgers K., Poindexter J.R. New methods of assessing crystal growth and saturation of brushite in whole urine: effect of pH, calcium and citrate. J. Urol. 2008. Vol. 180. Pp. 1532–1537.

10. Saw N.K., Rao P.N., Kavanagh J.P. A nidus, crystalluria and aggregation: key ingredients for stone enlargement. Urol. Res. 2008. Vol. 36. Pp. 11–15.

11. Türk C., Knoll T., Petrik A. [et. al.]. Guidelines on Urolithiasis. European Association of Urology. Arnhem. 2014. 1170 p.

12. Turney B.W., Reynard J.M., Noble J.G., Keoghane S.R. Trends in urological stone disease. BJU Int. 2011. Vol. 109, N 7. Pp. 1082–1087.

13. Tang R., Nancollas G.H., Giocondi J.L. [et. al.]. Dual roles of brushite crystals in calcium oxalate crystallisation provide physicochemical mechanisms underlying renal stone formation. Kidney Int. 2006. Vol. 70. Pp. 71–78.