The composition of urinary stones in the Sudan

Seventy-eight urinary stones from the Sudan were analysed quantitatively; 75.6% of upper urinary tract (UUT) stones and 37.8% of lower tract (LUT) stones were composed of pure calcium oxalate monohydrate. The composition of adult UUT stones in the Sudan is almost identical to that of similar stones from Leeds except that the former contain much more calcium oxalate and much less calcium phosphate. A smaller proportion of adult LUT stones from the Sudan contain magnesium ammonium phosphate and a larger proportion contain uric acid/urate than similar stones from Leeds. Juvenile LUT stones from the Sudan probably contain more calcium oxalate and less uric acid/urate than juvenile bladder stones in some other developing countries.     

The clinical study of 794 patients with an upper urinary tract stone analyzed by infrared spectroscopy

During the 48-year period from January, 1938 to December, 1985, upper urinary tract stones obtained from 794 patients were analyzed by infrared spectroscopy in our Department. Their clinical manifestations were studied, mainly in relation to stone composition. The ratio of males to females was 3.0 to 1. In recent years, the incidence of females tended to increase. In the age distribution, twenties were most frequent followed by thirties together with fourties before 1965, but after 1966, the thirties were most frequent, and fourties and fifties increased. The composition of 794 stones was as follows. The most frequent type was calcium oxalate combined with calcium phosphate (43.1%), followed by calcium oxalate (39.8%) and calcium phosphate (9.6%). Magnesium ammonium phosphate stones were found in 1.6% and uric acid stones in 2.9%. Calcium oxalate stones, uric acid stones and oxalate-containing stones were found more frequently in males than in females. On the other hand, magnesium ammonium phosphate stones, calcium phosphate stones and phosphate-containing stones were found less frequently in males than in females. There was a high occurrence of calcium phosphate stones and uric acid stones in patients older than 60 years old. The occurrence of calcium oxalate stones and uric acid stones increased and that of phosphate-containing stones decreased after 1966. Most of the recurrent stones revealed the same or similar composition as the initial stones.     

An architectural study of mixed uric acid and calcium oxalate stones by polarized light microscopy of thin section

The architecture of mixed uric acid and calcium oxalate stones was studied by polarized light microscopy. Some uric acid stones contained calcium oxalate stones (whewellite or weddellite) as a nucleus. Other uric acid stones contained calcium oxalate crystals in the nucleus or inner portion. A uric acid stone covered with layers of calcium oxalate was also found. In the mixed stones, nuclei of randomly mixed fine grained whewellite and uric acid were seen and both crystals appeared in alternating sequence in the outer layers. Weddellite crystals dissolved layers of uric acid and invaded into them in the nuclear or peripheral zones. Whewellite may precipitate in the same or a similar condition as uric acid precipitates, whereas weddellite may precipitate in a different condition. We discussed the pathogenesis of mixed uric acid and calcium oxalate stones, heterogeneous nucleation and epitaxial growth based on a morphologic study of the mixed stones.     

232例湖北地区泌尿系结石红外光谱成分分析

目的：分析湖北地区泌尿系结石化学成分的构成,为本地区结石的防治提供依据。方法：采用结石红外光谱自动分析系统对2011年11月～2012年8月期间收集到的湖北地区泌尿系结石232例进行成分分析。结果：232例结石中,各成分的检出率为：一水草酸钙（COM）85．34％,二水草酸钙（COD）62．93％,碳酸磷灰石（CA）24．14％,无水尿酸（UA）12．93％,二水磷酸氢钙（PH）4．31％,磷酸铵镁（MAP）6．90％,黄嘌呤1．29％,胱氨酸（CYS）1．29％,方解石0．86％,尿酸铵（AU）0．86％。含草酸钙成分结石86．21％,含磷酸钙成分结石28．45％,含磷酸铵镁成分结石6．90％,含尿酸成分结石13．79％,含胱氨酸成分结石1．29％。混合成分结石181例（78．02％）,尿路结石发病男性多于女性,男女比例为3．14：1。结论：湖北地区泌尿系结石以混合性结石为主,COM检出率最高,其次为COD。结石成分分析对于结石的防治有重要意义。     

结石红外光谱自动分析系统在尿路结石成分分析中的应用

目的 评价红外光谱自动分析系统检测尿路结石成分的临床应用价值.方法 尿路结石标本1450例.男1032例,女418例.年龄6个月～88岁.男性平均年龄(41.7±15.3)岁,女性(42.0±15.6)岁.肾结石875例(60.34%),输尿管结石504例(34.76%),膀胱结石71例(4.90%).均采用LIIR型结石红外光谱自动分析系统分析.解析结果均行红外光谱人工解析验证,必要时辅以偏光显微镜、X线衍射或化学方法进行验证. 结果在结石总体构成比上,一水草酸钙结石714例(49.24%),碳酸磷灰石结石444例(30.62%),无水尿酸结石93例(6.41%),二水草酸钙结石92例(6.34%),六水磷酸铵镁结石28例(1.93%),胱氨酸结石23例(1.59%),尿酸铵结石20例(1.38%),二水尿酸结石16例(1.10%),二水磷酸氢钙结石12例(0.83%),一水尿酸钠结石2例(0.14%),碳酸钙结石1例(0.07%),其他5例(0.34%).结石的组合成分上,混合性结石1053例(72.62%),单一成分结石仅397例(27.38%).混合性结石主要为含钙类结石.其中15例婴幼儿结石为食用三聚氰胺污染奶粉所致,成分为二水尿酸与尿酸铵的混合结石.验证结果表明,结石主要成分误检6例(0.41%),将无水尿酸误检为尿酸铵或碳酸磷灰石;漏检9例(0.62%),其中漏检六水磷酸铵镁或碳酸磷灰石7例,性质不明2例.在2种和3种成分的混合性结石中,含量相对低的成分各漏检6例和10例,均为六水磷酸铵镁或碳酸磷灰石. 结论结石红外光谱自动分析系统分析尿路结石成分具有准确、自动、快捷等优点,适合临床常规使用.

Abstract：

Objective To determine the value of applying LIIR Automatic Analysis System of Infrared Spectroscopy in analyzing urinary stone composition. Methods 1450 samples of urinary stones were collected from 1032 male and 418 female patients. The age of patients ranged from 6 months to 88 years. The mean ages were 41.7±15.3 and 42.0±15.6 years for male and female patients, respectively. Of 1450 stones, 875 cases were located in kidney (60.34%), 504 cases in ureter (34.76%) and 71 cases in bladder (4.90%). All stones were analyzed by LIIR Automatic Analysis System of Infrared Spectroscopy (Tianjin). Analysis results were reevaluated by the artificial analysis of spectrogram, if necessary, with polarization microscope, chemical analysis, and X-ray diffraction.Results Calcium oxalate monohydrate stones were found in 714 cases (49. 24%), carbonate apatite stones in 444 cases (30.62%), anhydrous uric acid stones in 93 cases (6.41%), calcium oxalate dihydrate stones in 92 cases (6. 34 % ), ammonium magnesium phosphate hexahydrate stones in 28 cases (1.93%), cystine stones in 23 cases (1.59%), ammonium urate stones in 20 cases (1.38%), uric acid dihydrate stones in 16 cases (1.10%), brushite stones in 12 cases (0.83%), sodium urate monohydrate stones in 2 cases (0. 14%), calcium carbonate stones in 1 cases (0. 07%), and other stone types in 5 cases (0. 34%). Most urinary stones were composed of 2 or more compositions, and pure stones were only observed in 397 cases (27.38%). Most of the mixed stones contained calcium and non-calcium mixed stone was rarely observed. In addition, 15 stones were found in infants who had consumed melamine-contaminated milk powder. These stones were composed of uric acid dihydrate and ammonium urate. The results of reevaluation by artificial analysis showed the following: among pure and mixed stones, false detection occurred in 6 cases (0.41%), of which the composition was ammonium urate or carbonate apatite determined by automatic system but the true composition was anhydrous uric acid. False negative detection occurred in 9 cases (0.62%), of which the composition was ammonium magnesium phosphate hexahydrate or carbonate apatite in 7 cases, but in other 2 cases the composition could not be determined by artificial analysis. The false negative detection of components with relatively low content occurred in 6 cases and 10 cases in stones with 2 components and 3 components, respectively. The undetected composition in these cases was ammonium magnesium phosphate hexahydrate or carbonate apatite. Conclusion Automatic Analysis System of Infrared Spectroscopy has many advantages in accuracy, automation and is quick in analyzing the composition of urinary stones, and is worthy of promotion in clinical use.     

Urolithiasis in Okinawa, Japan: A relatively high prevalence of uric acid stones

AIM: The aim of the present study was to investigate the composition of urinary tract stones in patients from Okinawa, the most southern island group of Japan. METHODS: The study was conducted by 12 hospitals in Okinawa. A total of 1816 urinary tract calculi were obtained from 1816 patients (1323 males; 493 females). The patients had a mean age of 53 +/- 15.3 years (mean +/- SD). The calculi were examined to determine their chemical composition. Stone samples were analyzed by computed infrared spectrophotometer. RESULTS: Pure stones comprised 58.4% of the total, with calcium oxalate stones accounting for 40% (21% monohydrate [whewellite]; 6.6% dihydrate [weddellite]; and 12.4% combined monohydrate and dihydrate stones), uric acid/urate stones for 9.6%, calcium phosphate stones for 5.1%, and struvite stones for 3.7%. The other 41.6% of the stones consisted of calcium oxalate mixed with other components. The male-to-female ratio was 2.7:1. CONCLUSION: In our series, calcium oxalate stones accounted for 81.6% of the urinary tract calculi, while uric acid/urate stones accounted for 15.8%. Uric acid stones, predominantly the anhydrous and/or dihydrate forms, showed a relatively high prevalence. Calcium oxalate stones, predominantly in the form of whewellite, showed a high prevalence among pure calculi; while the predominant combinations among mixed calculi were weddellite + calcium phosphate and whewellite + uric acid/urate.     

Composition of urinary tract calculi from some developing countries.

The composition of 142 calculi from Sudan, Thailand, Indonesia and Saudi Arabia has been determined by qualitative and quantitative chemical analysis. Calcium oxalate was the commonest constituent of both kidney and bladder stones, followed by magnesium ammonium phosphate, ammonium acid urate, calcium phosphate, uric acid and cystine in that order. Calcium oxalate was also the main constituent of the nucleus of most kidney and bladder stones, calcium phosphate, magnesium ammonium phosphate, and ammonium acid urate occurring most frequently in the outer layers of the stones. Most endemic bladder stones appear to originate as aggregates of calcium oxalate crystals in the kidney, which subsequently descend to the bladder, where they may acquire secondary deposits of calcium phosphate, magnesium ammonium phosphate or ammonium acid urate.     

广东东莞地区416例泌尿系结石成分分析

目的 应用红外光谱法测定东莞地区泌尿系结石化学成分,探讨本地区泌尿系结石患者的尿路结石成分特点,为本地区泌尿系结石的深化治疗、防止结石复发及预防提供科学依据.方法 收集经自行排出、碎石后排出或手术中取出的泌尿系结石标本416例,应用溴化钾压片技术的红外光谱法对其化学成分进行定性分析.结果 416例泌尿系结石患者中男性居多,占66.8%(278/416),女性占33.2%(138/416);上尿路结石占88.2%,下尿路结石(膀胱结石居多)占11.8%;结石成分定性分析共检测出一水草酸钙、二水草酸钙、碳酸磷灰石、无水尿酸、六水磷酸铵镁和尿酸铵6种化学成分.单一成分结石163例(一水草酸钙/无水尿酸/碳酸磷灰石/六水磷酸铵镁:98/56/6/3),占39.2%;混合成分结石253例,占60.8%,其中以草酸钙和碳酸磷灰石的混合结石为主(188/253).所有结石标本中草酸钙检出率最高,占80.5%(335/416),其次为碳酸磷灰石(49.3%)及无水尿酸(17.3%);膀胱结石成分以一水草酸钙或无水尿酸为主.结论 东莞为全国泌尿系结石最高发地区,其结石成分以草酸钙和碳酸磷灰石为主,单一成分结石亦占相当比例.尿路结石成分分析对了解结石成因可提供重要的线索,对临床制定个性化治疗方案、预防结石形成及复发具有重要意义.     

gamma-Carboxyglutamic acid, a component in human pediatric bladder stones containing calcium salts

The amino acid gamma-carboxyglutamic acid (Gla) has been previously detected in the vitamin K-requiring blood clotting factors, proteins of calcified vertebrate tissue, renal tissue, plasma protein C, ectopic calcifications, and calcium-containing renal calculi. This paper reports the presence of Gla in the EDTA-soluble, non-dialyzable material recovered from human pediatric bladder stones containing calcium salts. In bladder stones composed of calcium oxalate, uric acid and ammonium acid urate, 73 Gla residues per 1,000 amino acid residues were detected. Bladder stones composed of calcium oxalate, uric acid, ammonium acid urate, and hydroxyapatite contained 48 Gla residues per 1,000 amino acid residues present. No Gla was detected in the predominantly magnesium ammonium phosphate (struvite) bladder stones. These results with human bladder stones from children under 10 years of age are consistent with the observations from adult patients in which Gla was detected in the calcium-containing renal calculi but not in the non-calcium-containing renal calculi. The present study adds to the growing body of information concerning the possible role of Gla in normal and abnormal calcium metabolism.     

426例陕西地区泌尿系结石红外光谱成份分析

目的探讨近年来陕西地区泌尿系结石成份构成情况,并根据结石成份构成指导泌尿系结石的治疗和预防。方法采用天津LIIR型结石红外光谱自动分析系统对426例陕西地区泌尿系结石标本进行成份分析。结果多种成份混合结石占72．30％;各成份的检出率为：一水草酸钙71．83％、碳酸磷灰石63．85％、二水草酸钙42．26％、无水尿酸11．03％、尿酸铵3．76％、磷酸铵镁3．29％。结论陕西地区泌尿系结石的主要成分为草酸钙,碳酸磷灰石和尿酸类结石。     

广东南海地区泌尿系结石患者结石成分分析(附986例报告)

【摘要】 目的 应用红外光谱法分析广东南海地区泌尿系结石患者的结石,为临床个性化防治泌尿系结石及复发提供理论依据。方法 通过自然排出、碎石后排出或手术取出获得结石样本986例,并应用红外光谱法对其行结石成分分析。结果 泌尿系结石患者男女比例为1.34∶1,51岁~60岁年龄阶段患者所占比例最高,上尿路结石发病人数明显多于下尿路结石,比例达9.49∶1。定性分析共检测出一水草酸钙、二水草酸钙、碳酸磷灰石、无水尿酸、六水磷酸镁铵和胱氨酸6种化学成分。混合成分结石647例,占总人数的65.6%;含钙结石853例,占86.51%。草酸钙检出率最高,占77.38%,其次是碳酸磷灰石(5.27%)和尿酸(13.29%)成分。结论 采用红外光谱法分析泌尿系结石成分,对于了解结石成因、预防结石形成和复发具有重要的意义。     

非增强螺旋CT平扫对上尿路结石成分预测的体内研究

目的 探讨非增强螺旋CT对体内上尿路结石化学成分的预测价值.方法 回顾性分析156例有结石标本的上尿路结石患者临床资料.所有患者在治疗前采用GE High speed CT/i螺旋CT机行非增强结石扫描,扫描参数为120 kV,320 mA,螺距0.6:1,扫描层厚为5 mm.在CT软组织窗测量结石平均CT值.将获取的结石样本采用红外光谱自动分析系统进行化学成分定性分析.经统计学分析,找出各种成分结石的相应CT值范围.结果 非增强螺旋CT扫描156例结石的软组织窗CT值范围为128～ 1663亨氏单位(hounsfield unit,HU).共发现纯结石57例,其中纯一水草酸钙结石28例,纯尿酸结石19例,纯羟基磷灰石10例,混合结石99例.一水草酸钙、尿酸、羟基磷灰石三种纯结石的软组织窗平均CT值分别为(915.4±142.9) HU、(469.7±55.1) HU、(868.4±168.8)HU.尿酸结石与一水草酸钙结石、尿酸结石与羟基磷灰石之间的CT值差异有统计学意义(P＜0.05).19例纯尿酸结石和137例其他成分结石的软组织窗平均CT值之间差异有统计学意义(P＜0.05).以结石的软组织窗平均CT值＜ 550 HU为标准诊断纯尿酸结石,其灵敏度为92.8％,特异度为98.1％,阳性预测值为88.5％,阴性预测值为99％,诊断符合率为98.1％.结论 非增强螺旋CT平扫用于判断上尿路结石成分效果满意.根据软组织窗CT值不同,可将体内尿酸结石与其他成分结石区分.软组织窗平均CT值＜550 HU可作为纯尿酸结石的诊断标准.     

Some data on urinary stones which were passed.

Out of a group of 979 patients with urinary calculi, 175 had passed their stone(s). Comparison of data for stones which had been passed with data for the whole group shows many significant differences. Calculi composed entirely of calcium oxalate are more likely to be expelled than any other composition variety. The chance of this happening is 1 in 3 and it is even higher when the person is under 50 years of age. The probability of calculi composed of calcium oxalate+calcium phosphate being expelled is 1 in 5 and this also increases for younger patients. Infection stones consisting of calcium phosphate+struvite have only 1 in 19 chance of being passed. Many of the stones passed (130) are under 0.10 g in weight. However, there is a similar relationshp between composition and weight among both the stones that were passed and the whole group. In both groups, pure oxalate stones are the lightest, infection stones are the heaviest and stones composed of calcium phosphate and calcium phosphate+calcium oxalate are of intermediate weight.     

螺旋CT扫描预测上尿路结石成分的体内研究

目的:研究螺旋CT对体内上尿路结石化学成分的预测价值。方法:2005年12月～2007年9月对157例上尿路结石患者在治疗前行螺旋CT平扫,测结石CT值。定量分析各种治疗方法所获取结石的化学成分。经统计学分析,找出不同成分结石的CT值范围。结果:一水草酸钙、尿酸、羟基磷灰石三种纯结石的软组织窗平均CT值分别为(851.50±188.74)HU、(446.92±47.20)HU和(835.53±110.58)HU。尿酸结石与一水草酸钙结石、尿酸结石与羟基磷灰石之间CT值的差异均有统计学意义。13例纯尿酸结石与144例尿酸含量小于70%的其他结石的CT值差异有统计学意义。以结石的软组织窗平均CT值500 HU为标准鉴别纯尿酸结石,其灵敏度为92.31%,特异度为96.53%,阳性预测值为70.59%,阴性预测值为99.29%。结论:结石的CT值可作为鉴别尿酸结石的一种方法,CT值小于500 HU的结石多考虑为尿酸结石。     

湖北省荆门地区泌尿系结石成分及特征分析

目的探讨湖北省荆门地区的泌尿系结石成分特征,为临床治疗和诊断提供参考。方法选取荆门市第一人民医院、沙洋县人民医院、钟祥市人民医院和京山县人民医院四院泌尿外科于2016年1月至2018年12月间收治的患者资料,将符合标准的2000例患者纳入研究,使用红外光谱法检测其结石成分,并结合患者一般资料进行分析。结果泌尿系结石患者中50~65岁人群患病率最高,为46.60%(932/2000);男性患者1297例(64.85%),为女性患者的1.85倍;其中≤12岁和>75岁患者中的男女比例比值最大,为3∶1。结石主要位于肾脏和输尿管,膀胱占比较少,尿道不常见。结石成分主要草酸钙,其次为碳酸磷灰石和尿酸类,胱氨酸和磷酸铵镁结石不常见;仅在女性患者中发现羟基磷灰石和磷酸氢钙结石(占0.5%~0.7%),同时女性磷酸铵镁成分明显比男性常见(P<0.001)。首发和复发患者结石成分占比大体相似,草酸钙结石占大部分,碳酸磷灰石结石常见,尿酸类和磷酸铵镁结石出现率不高,胱氨酸、羟基磷灰石和磷酸氢钙结石不常见。结论湖北省荆门地区泌尿系结石草酸钙成分和肾脏发病最为常见,男女结石部分成分存在差异,可为该地区临床针对性预防和治疗提供参考。     

Relationship of frequency, age, sex, stone weight and composition in 15,624 stones: comparison of resutls for 1980 to 1983 and 1995 to 1998

PURPOSE: We studied the relationship of stone frequency and composition to age, sex and stone weight. MATERIALS AND METHODS: A retrospective study was performed of all 15,624 stones submitted for analysis with infrared and wet chemical methods in Newfoundland and Labrador from 1979 to 1998. RESULTS: There were 1,067 bladder stones of which 216 contained magnesium ammonium phosphate. The remaining 14,557 stones were from the kidney and ureter, and 11,707 were composed only of calcium oxalate and/or phosphate. Of the remaining 2,850 kidney and ureter stones magnesium ammonium phosphate was present in 573, uric acid/urate without magnesium ammonium phosphate in 1,109 and other compounds in 1,168. The 11,707 oxalate phosphate group was subdivided by infrared peak analysis based on oxalate-to-phosphate ratio into phosphate-ratio 1 or less, intermediate-1 to 10 and oxalate-10+. Oxalate comprised 65% of the 11,707 stones compared to 16% for phosphate. Women submitted 52% of phosphate stones compared with 28% of oxalate stones. From the first (1980 to 1983) to the last (1995 to 1998) complete 4-year study periods, there was a relative increase in oxalate and decrease in phosphate stones, associated with increasing age from decades 5 to 6 for oxalate and phosphate stones, except that the age peak for phosphate stones in women remained in decade 3. Median weight of 1, 828 phosphate stones was 43 mg. (mean 234) compared with 25 mg. (mean 98) for 7,634 oxalate stones. Male-to-female ratio was 0.91 for phosphate stones compared with 2.62 for oxalate stones. CONCLUSIONS: Phosphate stones were on average heavier and relatively more common in women, had an earlier age peak frequency in women than oxalate stones and became less frequent during our last 4-year study period. In contrast, oxalate stones were much more common, of lighter weight and became more frequent with time.     

Some features of paediatric urolithiasis in a group of Syrian children

A group of 28 Syrian children (19 males and 9 females; age ranging from 2.5 to 12 years) were diagnosed clinically and radiologically to have upper urinary tract stones. The commonest presentations were renal colic, vomiting, haematuria, pyrexia and vague abdominal pain. Family history of renal stones was present in 21% of cases. Haematological picture and chemical analysis of blood were within the normal limits for their age and sex. Urine analysis, however, showed significantly marked increase in the 24-hour excretions of calcium and uric acid. Microscopic examination showed haematuria and pyuria in 72% of the children with urolithiasis. Chemical analysis of removed stones revealed that most of them were mixed stones of calcium oxalate and urate or/and phosphate. Pure stones of calcium oxalate or calcium phosphate were less common. Radiologically, about 95% of all stones were demonstrated by plain X-ray, while 5% only after IVP.     

Comparison of matrix proteins in different types of urinary stone by proteomic analysis using liquid chromatography–tandem mass spectrometry

Objectives: To analyze the crystal components and matrix proteins of urinary stones by proteomic analysis using liquid chromatography–tandem mass spectrometry. Methods: Urinary stones were obtained from patients with gout and hyperuricemia. The outside and inside of the stones were measured non‐destructively with a micro area X‐ray diffractometer. After stones were powdered, extracted proteins were analyzed by proteomic analysis. Results: Of 17 investigated stones, seven were composed of calcium oxalate monohydrate or calcium oxalate dihydrate, seven were of uric acid, and three were a mixture of calcium oxalate monohydrate and uric acid. In calcium oxalate monohydrate or calcium oxalate dihydrate stones, osteopontin, uromodulin, albumin, protein Z, prothrombin, protein S, hemoglobin and histone H4 were identified. In uric acid stones, uromodulin, albumin, hemoglobin, calgranulins and immunoglobin G fragments were detected. Mixed stones of calcium oxalate monohydrate and uric acid contained both Ca‐binding proteins and abundant proteins. Matrix proteins were different when the crystal components of the stone were different, even when from the same patient. Conclusions: Proteins, such as uromodulin and albumin, are often detected in stones, regardless of crystal components. However, osteopontin, prothrombin, protein S and protein Z are identified specifically in calcium oxalate stones. Furthermore, immunoglobin G fragments are detected in uric acid stones. The role of these specific proteins in the different types of stones can be of particular interest.     

Divergence between stone composition and urine supersaturation: clinical and laboratory implications

PURPOSE: In general high urine supersaturation with respect to calcium oxalate, calcium phosphate or uric acid is associated with that phase in stones. We explore the exceptions when supersaturation is high and a corresponding solid phase is absent (type 1), and when the solid phase is present but supersaturation is absent or low (type 2). MATERIALS AND METHODS: Urine supersaturation values for calcium oxalate, calcium phosphate and uric acid, and other accepted stone risk factors were measured in 538 patients at a research clinic and 178 at stone prevention sites in a network served by a single laboratory. RESULTS: Of the patients 14% lacked high supersaturation for the main stone constituent (type 2 structural divergence) because of high urine volume and low calcium excretion, perhaps from changes in diet and fluid intake prompted by stones. Higher calcium excretion and low urine volume caused type 1 divergences, which posed no clinical concern. CONCLUSIONS: Type 1 divergence appears to represent a condition of low urine volume which raises supersaturation in general. Almost all of these patients are calcium oxalate stone formers with the expected high supersaturation with calcium oxalate as well as high uric acid and calcium phosphate supersaturations without either phase in stones. Type 2 divergence appears to represent an increase in urine volume and decrease in urine calcium excretion between stone formation and urine testing.     

Analysis of spontaneously passed urinary tract stones

Most studies on epidemiology, composition, and recurrence of renal calculi include both spontaneously passed calculi and those retrieved after surgical manipulation or shock wave lithotripsy. The present study exclusively focused on epidemiology, composition, and recurrence of spontaneously expelled stones in patients from North and East Mallorca (Spain) which represents a geographically specific non-urban region of a developed country. The study involved 136 patients who spontaneously passed 205 renal calculi. All calculi were classified and sub-classified according to composition after macroscopic and microscopic examination. We also analyzed prevalence, gender, age, and stone recurrence rate over a period of 3 years. The peak incidence of spontaneously stone passage is within the fourth to sixth decade. Overall male to female ratio was 3/1. Calcium oxalate was the most prevalent composition (64.8%) followed by uric acid (25.3%), mixed stones (5.3%) and calcium phosphate calculi (4.3%). Uric acid stones were the most recurrent (50%) followed by calcium oxalate monohydrate papillary calculi (26.4%), calcium oxalate monohydrate un-attached calculi (19.2%), calcium oxalate dihydrate calculi (18.3%), calcium phosphate calculi (14%), and mixed calculi (12.5%). In conclusion, spontaneously passed stones in Mallorcan population have similar epidemiology, composition, and recurrence rate from that found in other developed countries. Calcium oxalate stones are largely the most spontaneously passed type of calculi and uric acid stones are the most frequently recurred. These findings are also found to be similar to those reported in previous studies examining both spontaneously and non-spontaneously passed stones.