Laterality of nephrocalcinosis in kidney stone formers with severe hypocitraturia

Study Type – Aetiology (case series)
Level of Evidence 4 What’s known on the subject? and What does the study add? Systemic urinary stone‐forming conditions such as hypocitraturia or cystinuria should theoretically lead to symmetric and diffuse stone formation. Small studies have shown that some patients with such conditions produce stones primarily on one side. No studies, however, have attempted to quantify the frequency at which such patients form stones asymmetrically. This study demonstrates that despite having a severe systemic condition such as hypocitraturia, patients frequently have asymmetric and focal nephrocalcinosis. This suggests that additional intrinsic local factors such as renal perfusion or vascular injury must also play a role in stone formation. OBJECTIVE To examine the hypothesis that the distribution of nephrocalcinosis in patients with severe hypocitraturia should be symmetric. PATIENTS AND METHODS Patients with profound hypocitraturia defined as a 24‐h urine citrate <50 mg at the time of initial presentation were identified from the metabolic stone clinic database at our academic medical center. Two independent blinded reviewers evaluated all of the abdominal radiographs for the segmental distribution of macroscopic nephrocalcinosis. RESULTS A total of 44 patients met study criteria, with an equal distribution of males and females and a mean age of 55.4 ± 13.7 years. Mean urinary citrate was 28 ± 11 mg/day. Nephrocalcinosis was present in at least one renal segment in 22 patients (50%). Of the 22 patients with nephrocalcinosis, 9 patients (41%) had unilateral nephrocalcinosis and 13 patients (59%) had bilateral nephrocalcinosis. Of the 35 kidneys with nephrocalcinosis, 14 kidneys (40%) had nephrocalcinosis in only one renal segment, 13 kidneys (37%) had nephrocalcinosis in two segments and eight kidneys (23%) had nephrocalcinosis involving all three segments. CONCLUSIONS Despite the systemic nature of severe hypocitraturia, nephrocalcinosis is frequently asymmetric and focal in nature. This suggests that local factors intrinsic to the renal medullary interstitium, such as vascular injury, must play a role in the formation of nephrocalcinosis. Further study to elucidate these intrinsic local factors may further improve the treatment and prevention of urinary stone disease.     

The pathogenesis of calyceal diverticular calculi

Controversy exists over whether metabolic factors or urinary stasis predominate in the pathogenesis of calyceal diverticular calculi. We performed a study to better define the effects urinary stasis and metabolic abnormalities have in the pathogenesis of calyceal diverticular stones. Twenty-nine patients who underwent percutaneous treatment of calyceal diverticular calculi were studied. All patients underwent 24 h urine collection to evaluate metabolic risk factors. In three patients, urine was sampled directly from the diverticulum for metabolic studies. The urinary stone risk parameters of the patients with calyceal diverticular stones (Tic SF) were similar to those of a well-characterized cohort of calcium oxalate stone formers (CaOx SF). When compared to a group of normal people, the Tic SF and CaOx SF were significantly more hypercalciuric and their urine was significantly more supersaturated with calcium oxalate. Urine aspirated directly from the diverticulum had the lowest SSCaOx when compared to ipsilateral and contralateral renal pelves. The urinary risk profiles of patients with diverticular calculi are similar to those of CaOx SF, suggesting a metabolic etiology of diverticular stones. However, the SS CaOx of urine aspirated directly from the diverticula is significantly lower than that of the renal pelves; these data support the hypothesis that urinary stasis significantly contributes to the pathogenesis of calyceal diverticular calculi. Taken together, it seems likely that calyceal diverticular calculi arise from a combination of metabolic abnormalities and urinary stasis.     

Metabolic abnormalities associated with calyceal diverticular stones

OBJECTIVE: To review the metabolic analyses of patients with calyceal diverticular stones who had surgical treatment of their calculi and to examine the effect of selective medical therapy on stone recurrence, as recent reports suggest that metabolic abnormalities contribute to stone development. PATIENTS AND METHODS: In all, 37 patients who had endoscopic treatment of symptomatic calyceal diverticular calculi were retrospectively reviewed. Stone composition and initial 24-h urine collections (24-h urinary volumes, pH, calcium, sodium, uric acid, oxalate, citrate, and the number of abnormalities/patient per collection) were compared with 20 randomly selected stone-forming patients (controls) with no known anatomical abnormalities. Stone formation rates before and after the start of medical therapy were calculated in the patients available for follow-up. RESULTS: Twelve of the diverticulum patients (five men and seven women) had complete 24-h urine collections, all of whom had at least one metabolic abnormality. Seven patients had hypercalciuria, four had hyperuricosuria and three had mild hyperoxaluria. The most common abnormality was a low urine volume; 11 of the 12 patients had urine volumes of <2000 mL/day (range 350-1950). Ten patients had hypocitraturia in at least one of the two 24-h urine samples; seven had low urinary citrate levels (172-553 mg/day) on both samples. The findings were similar in the control group. The diverticulum patients had 3.1 abnormalities/patient, and the controls had 2.9 abnormalities/patient (P > 0.05). No patients had gouty diathesis and none developed cystine stones. Stone analyses were similar in the two groups; both developed either calcium oxalate or mixed calcium oxalate/calcium phosphate stones. Six patients were followed for a mean of 23.1 months while on selective medical therapy; only one passed any additional stones, thought to be existing calculi, for a remission rate of five of six (83%). CONCLUSIONS: All patients with symptomatic calyceal diverticular stones who had comprehensive metabolic evaluation had metabolic abnormalities. There were similar abnormalities in the control random stone-formers. The abnormalities were corrected with selective medical therapy, as shown by the high remission rate. We recommend that, for patients with symptomatic calyceal diverticular calculi, a metabolic evaluation should be considered to determine stone forming risk factors.     

Metabolic risk factors in children with kidney stone disease

The evaluation of metabolic risk factor in children with renal stone disease is the basis of medical treatment aimed at preventing recurrent stone events and the growth of preexisting calculi. In this retrospective study, we evaluated the metabolic risk factors and clinical and family histories of 90 children with kidney stone disease who had been referred to our institution and subjected to clinical tests using a standardized protocol. The mean age of our pediatric patients was 10.7 years, and the male:female ratio was 1.14:1.0. Biochemical abnormalities were found in 84.4% of all cases. A single urine metabolic risk factor was present in 52.2% (n = 47) of the patients, and multiple risk factors were present in the remaining 31.1% (n = 28). Idiopathic hypercalciuria (alone or in combination) and hypocitraturia (alone or in combination) were the most frequent risk factors identified in 40 and 37.8% of these patients, respectively. Renal colic or unspecified abdominal pain were the most frequent forms of presentation (76.9%), with 97.5% of stones located in the upper urinary tract. In most patients, stone disease was confirmed by renal ultrasonography (77%). A positive family history in first-degree and second-degree relatives was found in 46.2 and 32.5% of the cases, respectively. We conclude that specific urine metabolic risk factors are found in most children with kidney stones and that hypocitraturia is as frequent as hypercalciuria. Very often there is a positive family history of renal stone disease in first- and second-degree relatives.     

Urinary acidification in renal stone patients from northeastern Thailand.

Hypokalemia, hypokaliuria and hypocitraturia are common findings in patients with renal stone disease in Northeastern Thailand. However, hyperchloremic metabolic acidosis seldom is seen. Therefore, we studied renal acidification in 29 renal stone disease patients who were living in rural Northeast Thailand. Baseline blood and average 24-hour urine biochemical parameters were measured. Hypokalemia, hypokaliuria and hypocitraturia were found in 10%, 83% and 93% of the patients, respectively. By multiple regression, urinary citrate excretion correlated positively with serum potassium and urinary potassium excretion, and negatively with urinary ammonium (r = 0.640, p = 0.005). An abnormal response to acid loading was found in only 1 patient. Thus, hypokaliuria and hypocitraturia in our renal stone disease subjects were infrequently due to distal renal tubular acidosis. Perhaps potassium depletion might be a contributing factor in these metabolic abnormalities.     

微创经皮肾镜取石术治疗马蹄肾结石9例报告

目的:探讨微创经皮肾镜取石术(MPCNL)治疗马蹄肾结石的可行性、安全性及有效性。方法:2008年11月~2013年6月采用MPCNL治疗马蹄肾结石患者9例11侧。结石直径平均2.1(1.1~3.1)cm。拔出输尿管支架管1个月后行彩超、腹部平片检查无残石或结石残块3mm视为取石成功。结果:9侧肾结石一期碎石清石取得成功,1侧肾结石行二期手术,1侧肾结石术后结石直径较小,未做处理。9例患者术后均未出现大出血、邻近器官损伤等情况。结论:采用MPCNL治疗马蹄肾结石是一种安全、有效的手术方式。     

Urolithiasis in children: Current medical management

The mechanism of stone formation in the urinary tract is reviewed. Diet, urinary tract infection and metabolic disorders account for the different epidemiological patterns of stone formation. The diagnosis and management of renal tract calculi are discussed. Calcium stones are associated with hypercalciuria, urine acidification defects, the use of furosemide in premature babies, hypercalcaemia, hyperoxaluria, hyperuricosuria, an alkaline urine and hypocitraturia. Uric acid stones occur in acid urine, from increased purine synthesis with lympho- or myeloproliferative disorders or from several inborn errors of purine metabolism which can also cause xanthine or dihydroxyadenine stones. Cystinuria, inherited as an autosomal recessive disorder is best treated with a low sodium diet, a fluid intake exceeding 40 ml/kg per day maintaining urine pH between 7.5 and 8 and, if necessary, with oral penicillamine. Oxalate stones occur in relation to diet, bowel disease and primary inherited defects in oxalate metabolism. Urinary tract infection causing struvite and carbonate apatite formation is the commonest cause of stones in Europe.     

A case of nephrocalcinosis due to Sj?gren syndrome associated with renal tubular acidosis

A 39-year-old women was admitted to the hospital because of fever, lumbago and recurrent history of spontaneous stone discharge. An abdominal X-ray film demonstrated multiple calculi in the medullary positions of both kidneys and right multiple ureteral stones. Laboratory examinations showed hypergammaglobulinemia and the urine pH level was fixed around 7; nevertheless general metabolic acidosis existed. These laboratory data indicated nephrocalcinosis due to Sj?gren syndrome associated with renal tubular acidosis. Right multiple ureteral stones were removed by transurethral ureteroscopy. After starting alkali therapy, neither increased nor recurrent stone formation was recognized.     

Metabolic risk factors in patients with ureteropelvic junction obstruction and renal calculi

PURPOSE: We performed a prospective study to determine the incidence and spectrum of metabolic abnormalities predisposing to stone formation in patients with ureteropelvic junction obstruction and renal calculi. MATERIALS AND METHODS: A total of 47 consecutive patients with congenital ureteropelvic junction obstruction underwent metabolic evaluation of stone risk factors. Of these patients 21 had associated stones (study group), while 26 did not (control group). Logistical regression, Wilcoxon rank sum and Fisher's exact tests were performed to determine whether there was a significant difference between these groups in regard to the presence of metabolic risk factors. RESULTS: Demographically and symptomatically the 2 groups were equivalent except that the study patients were older. The 24-hour urinary excretion of calcium was significantly higher in study than in the control patients (p = 0.007). While the incidence of hypercalciuria and hyperuricosuria was also higher in the study population, these differences were not significant (p = 0.08 and 0.07, respectively). CONCLUSIONS: Metabolic abnormalities predisposing to stone formation are present more frequently in patients with ureteropelvic junction obstruction who have associated stones compared to those who do not. As such, urinary stasis alone does not explain stone formation in these cases. Rather, the local physiological environment of urine likely has a predisposing role. In addition to restoring unobstructed urinary flow, consideration should be given to metabolic evaluation and prophylactic treatment for affected patients.     

Flexible ureteroscopy for lower calyceal stones in a horseshoe kidney – Is it the new treatment of choice?

IntroductionThe efficacy of retrograde intrarenal surgery (RIRS) for the treatment of disorders in a horseshoe kidney has not been sufficiently studied so far. We report on our experience with this method for the treatment of lower-pole calculi in patients with a horse-shoe kidney.Patients and methodsThe files of 9 patients who underwent RIRS for lower calyceal stones in horseshoe kidneys between April 2012 and December 2014 were retrospectively analyzed. The stone-free status, postoperative complications, operative time and duration of hospitalization were assessed.ResultsIn total, 12 renal units with lower calyceal stones were treated, as 3 patients had stones in both kidneys. In 8 renal units complete stone clearance could be achieved in one sitting (67.7%), while in 3 renal units 2 sittings were necessary in order to achieve stone clearance. One patient with a stone sized 18 mm still had residual stones after two sittings and, therefore, underwent percutaneous nephrolithotomy (PCNL) for stone clearance. No major complications (Clavien–Dindo grades III–V) were encountered.ConclusionRIRS for the treatment of stone disease in horseshoe kidneys has been shown to be a relatively safe and effective procedure. However, due to the anatomical abnormality, a second look may be needed to render the patient completely stone-free.     

Percutaneous nephrolithotomy in horseshoe kidneys. Applied anatomy and clinical experience

The arterial supply of horseshoe kidneys was studied in 6 anatomical specimens to establish whether there is a risk of haemorrhage when performing percutaneous nephrolithotomy. The anatomy of the collecting system was studied on patients' X-rays, taken in different planes to obtain a three-dimensional view. It was found that there is no increased risk of arterial bleeding in horseshoe kidneys compared with normal kidneys. The orientation of the collecting system offers good access. Eight patients with horseshoe kidneys and 1 with a malrotated kidney were treated with percutaneous nephrolithotomy because of solitary or multiple renal pelvic and caliceal stones and 1 ureteric stone. Four patients had had previous operations for calculi. All of the stones were removed without complications.     

The etiology of urolithiasis in HIV infected patients

PURPOSE: It is commonly thought that urinary lithiasis in HIV infected patients on protease inhibitor therapy is composed primarily of the protease inhibitor itself. Since many HIV infected patients on protease inhibitors presenting to our institution had nonprotease inhibitor stones, we investigated potential underlying metabolic abnormalities that may account for the lithogenesis. MATERIALS AND METHODS: We retrospectively reviewed all HIV infected patients on protease inhibitors with renal colic and evidence of nephrolithiasis who presented to our institution between June 1996 and January 2001. Patients were evaluated for stone composition and metabolic abnormalities of blood and urine when possible. RESULTS: A total of 24 patients were identified, and all were or had been on protease inhibitors (indinavir 14, ritonavir 3, nelfnavir 2, unspecified 5). Of the 14 patients on indinavir only 4 (28.6%) had indinavir containing stones. The remaining stones in this group and in those not on indinavir contained various amounts of calcium oxalate monohydrate and dihydrate, ammonium acid urate and uric acid. Of 10 patients who underwent 24-hour urine collection for metabolic evaluation 8 (80%) had abnormalities, including hypocitraturia in 5, hyperoxaluria in 4, hypomagnesuria in 4, hypercalciuria in 3, increased supersaturation of calcium oxalate in 3 and hyperuricosuria in 2. Abnormalities in the levels of urinary phosphate and sodium were also observed. CONCLUSIONS: HIV infected patients form many types of stones, which probably are attributable to underlying metabolic abnormalities rather than the use of protease inhibitors. A complete metabolic evaluation is warranted in these patients, as a means of guiding treatment to prevent future stone episodes, while avoiding the need to alter antiretroviral regimens.     

Endoscopic evidence of calculus attachment to Randall's plaque

PURPOSE: It has been proposed that calcium oxalate calculi begin as small stones attached to the renal papillae at sites of Randall's plaque. However, no study has investigated the prevalence of attached stones in calcium oxalate stone formers or the relationship between stone attachment site and Randall's plaque. In this study we used endoscopic examination of renal papillae in stone formers undergoing percutaneous nephrolithotomy to investigate both issues. MATERIALS AND METHODS: Idiopathic calcium oxalate stone formers undergoing PNL for stone removal were enrolled in this study. Multiple papillae were examined and images were recorded by digital video. The presence or absence of papillary plaque and attached stones was noted, as was the site of stone attachment. RESULTS: In 23 patients, 24 kidneys and 172 renal papillae were examined. All kidneys were found to have papillary plaque and 11 of the patients had attached stones. Most papillae (91%) contained plaque. CONCLUSIONS: The prevalence of attached stones in calcium oxalate stone formers (48%) is greater than that previously reported for the general population. Attachment appears to be on Randall's plaque. The high prevalence of attached stones and the appearance of the attachment site are consistent with a mechanism of calcium oxalate stone formation in which stones begin as plaque overgrowth.     

Metabolic risk factors in patients with renal stones in KwaZulu Natal: an inter-racial study (Asian and Whites)

OBJECTIVE: To identify any differences between Whites and Indians in KwaZulu Natal province, South Africa, in the metabolic risk factors which predispose them to urinary stone formation. PATIENTS AND METHODS: Urinary stone disease is often a manifestation of an underlying metabolic disorder in most patients. Intrinsic and extrinsic factors affect the susceptibility of an individual to develop urinary stones. Although South African-born Indians and Whites in KwaZulu Natal share some of the same extrinsic factors, diet and genetic factors differ between the groups. In a study from April 1999 until April 2001, 140 patients were included who had a radiological diagnosis of renal calculi; they were evaluated metabolically using previously recommended methods. RESULTS: All the patients had at least one identifiable metabolic risk factor; the prevalence of the common metabolic risk factors was similar in the two groups. The prevalence of complete renal tubular acidosis (type 1) was significantly higher in the Indian patients. The most common metabolic abnormalities were hypomagnesuria and hypocitraturia, followed by low urinary volume. Hypercalciuria was not significant in this population. While Indians had lower urine volumes than Whites, Whites had significantly higher urinary calcium excretion than Indians. CONCLUSION: There were a few variations in the metabolic risk factors between Indians and Whites, and the differences could be attributed to genetic or dietary habits. The high incidence of renal tubular acidosis in Indian patients could explain the higher prevalence of urinary stone disease in this group than in other racial groups.     

Treatment of calculi in kidneys with congenital anomalies: an assessment of the efficacy of lithotripsy

We studied the effectiveness of extracorporeal shock wave lithotripsy (ESWL) in the treatment of stones in kidneys with congenital anomalies to determine factors that may affect the results. Patients found to have renal calculi in kidneys with different types of congenital anomalies were treated using ESWL. All patients were investigated by intravenous urography (IVU) to confirm the diagnosis. J stents were inserted prior to therapy in renal units with calculi exceeding 1.5 cm in diameter. Complications encountered and factors affecting success using this treatment modality were analysed. Twenty-five patients (18 males, 7 females) were studied between August 1988 and July 2005. There were nine patients with horseshoe kidneys, eight with ectopic kidneys, three with malrotated kidneys, two with duplex renal system, and one patient each with polycystic kidneys and hypoplastic kidney. The IVU showed 31 isolated calyceal or renal pelvic stones with mean stone burden of 1.44cc. All 25 patients were treated by lithotripsy. Twenty-four (77.4%) renal units (in 19 patients) were completely cleared of stones, 2 (6.5%) renal units (2 patients) were partially cleared of calculi and the procedures failed in 5 (16.1%) renal units (4 patients). Out of five renal units in which the procedures failed, open surgery was performed in three renal units and percutaneous nephrolithotomy (PCNL) was performed in two. None of the 25 patients developed any major complications. No significant adverse changes in renal function tests were observed at 3-month follow-up. The stone-free rate was influenced and reduced by stone size and location in the pelvi–calyceal system. Calculi in kidneys with congenital anomalies may be treated successfully by ESWL as a first-line therapy in the majority of patients. With position modifications, localization of stones may be facilitated and disintegrated. The outcome in patients so treated does not differ significantly from that in those with normal kidneysThis paper was presented as a poster at the 11th European Symposium on Urolithiasis, Coburg, Germany. June 16–18, 2005. Poster No ESWL 8.     

微创经皮肾取石术治疗先天性异常肾合并结石

目的探讨微创经皮肾镜取石术（minimally invasive percutaneous nephrolithotomy,MPCNL）治疗先天性异常肾合并结石的疗效。方法2000年1月～2007年11月,采用MPCNL治疗异常肾合并结石41例,其中马蹄肾12例,重复肾19例,旋转肾10例。单发上盏结石4例,中盏6例,下盏7例,肾盂结石3例,重复肾上肾结石4例,多发结石12例,鹿角形结石5例。结石最大直径1.0～4.0 cm,平均2.5 cm。13例合并输尿管中上段结石同时取石。结果41例均一次穿刺成功。手术时间45～210 min,平均95 min。术中出血30～150 ml,平均80 ml。一期结石清除率85.4%（35/41）,2例马蹄肾和1例重复肾患者经二次取石取净,2例重复肾和1例旋转肾患者术后配合体外冲击波碎石治疗。1例旋转肾MPCNL术后发生较严重出血（800 ml）,经高选择性动脉栓塞后治愈,其余未见严重并发症发生。41例随访5～12个月,平均6个月,无结石复发。结论MPCNL治疗先天性异常肾合并结石安全、可靠。但仍需强调个体化的原则,根据不同异常肾的类型,结石大小、位置等情况进行操作。     

Calcium phosphate supersaturation regulates stone formation in genetic hypercalciuric stone-forming rats

BACKGROUND: Hypercalciuria is the most common metabolic abnormality observed in patients with nephrolithiasis. Hypercalciuria raises urine supersaturation with respect to the solid phases of calcium oxalate and calcium phosphate, leading to an enhanced probability for nucleation and growth of crystals into clinically significant stones. However, there is little direct proof that supersaturation itself regulates stone formation. Through successive inbreeding of the most hypercalciuric progeny of hypercalciuric Sprague-Dawley rats, we have established a strain of rats, each of which excrete abnormally large amounts of urinary calcium and each of which forms calcium phosphate kidney stones. We used these hypercalciuric (GHS) rats to test the hypothesis that an isolated reduction in urine supersaturation, achieved by decreasing urine phosphorus excretion, would decrease stone formation in these rats. METHODS: Thirty 44th-generation female GHS rats were randomly divided into three groups. Ten rats received a high-phosphorus diet (0.565% phosphorus), 10 a medium-phosphorus diet (0.395% phosphorus), and 10 a low-phosphorus diet (0.225% phosphorus) for a total of 18 weeks. The lowered dietary phosphorus would be expected to result in a decrease in urine phosphorus excretion and a decrease in urinary supersaturation with respect to the calcium phosphate solid phase. Every two weeks, 24-hour urine collections were obtained. All relevant ions were measured, and supersaturation with respect to calcium oxalate and calcium hydrogen phosphate were determined. At the conclusion of the experiment, each rat was killed, and the kidneys, ureters, and bladder were dissected en block and x-rayed to determine whether any stones formed. A decrease in stone formation with a reduction in urinary supersaturation would support the hypothesis that supersaturation alone can regulate stone formation. RESULTS: Decreasing the dietary phosphorus intake led to a progressive decrease in urine phosphorus excretion and an increase in urine calcium excretion, the latter presumably caused by decreased intestinal calcium phosphate binding and increased calcium absorption. With decreasing dietary phosphorus intake, there was a progressive decrease in saturation with respect to the calcium phosphate solid phase. Fifteen of the 20 kidneys from the 10 rats fed the high-phosphorus diet had radiographic evidence of kidney stone formation, whereas no kidneys from the rats fed either the medium- or low-phosphorus diet developed kidney stones. CONCLUSIONS: A decrease in urine phosphorus excretion not only led to a decrease in urine supersaturation with respect to the calcium phosphate solid phase but to an elimination of renal stone formation. The results of this study support the hypothesis that variation in supersaturation alone can regulate renal stone formation. Whether a reduction of dietary phosphorus will alter stone formation in humans with calcium phosphate nephrolithiasis remains to be determined.     

Metabolic risk factors and the effect of metaphylaxis in pediatric stone disease with hypocitraturia

To describe the metabolic risk factors and investigate the effect of prophylaxis based on these factors on long-term recurrence of urolithiasis in pediatric patients with hypocitraturia. One-hundred and twenty-nine pediatric patients who underwent percutaneous nephrolithotomy between January 2008 and June 2011 were evaluated for metabolic risk factors. The patients with hypocitraturia were enrolled in this study and the data were analyzed using statistical methods for a mean period of 2 years for metabolic abnormalities, stone type, and the effect of potassium citrate prophylaxis on stone recurrence. A 24-h urine metabolite analysis revealed one or more metabolic risk factors in 115 (89.2 %) of the patients, whereas 14 (10.8 %) of the patients had no metabolic abnormalities. Eighty-two (63.5 %) of 129 patients had hypocitraturia. Of them, 43 (52 %) were male and 39 (48 %) were female, with a mean age of 9.7 ± 4.9 and 6.7 ± 4.4 (1–16) years, respectively(p = 0.102). Thirty-five (42.7 %) had pure hypocitraturia, and 47 (57.3 %) had two or more metabolic abnormalities. The most common dual metabolic abnormality was hypocitraturia and hypomagnesuria. Seventy-one patients (87 %) with hypocitraturia received medical prophylaxis and continued regularly, whereas 11 (13 %) patients did not receive medical prophylaxis despite being advised to do so. After a mean follow-up of 26.5 ± 9.4 months, the rate of recurrence was 1.4 % in the patients with hypocitraturia who continued prophylaxis and occurred in all of the patients who did not receive prophylaxis (p < 0.001). Calcium oxalate stones (95.2 %) were the most commonly found stones in the stone analysis. Detailed clinical and laboratory evaluations should be performed in children with urolithiasis. Appropriate prophylactic treatment as potassium citrate, should be given to prevent reformation of stones in patient with hypocitraturia.     

Management of urolithiasis in the congenitally abnormal kidney (horseshoe and ectopic)

PURPOSE OF REVIEW: Urolithiasis in horseshoe and ectopic kidneys presents unique challenges in the decision-making and technical aspects of stone treatment. Specific renal anatomy, stone size and associated conditions such as ureteropelvic junction obstruction are factors that may influence treatment. Detailed review of imaging is important to ensure efficient stone treatment and minimize complications. RECENT FINDINGS: Widespread use of extracorporeal shockwave lithotripsy for calculi in congenitally abnormal kidneys is now giving way to stone-size and anatomy-appropriate therapeutic decision making. Multiple modalities including shockwave lithotripsy, ureteroscopy, percutaneous nephrolithotomy and laparoscopy are being employed in this group of patients. SUMMARY: Treatment decisions for stones in horseshoe and ectopic kidneys can be challenging, and must be made on an individual basis taking into account multiple variables.     

GERIATRIC UROLITHIASIS

Purpose

We define the differences between geriatric patients with urinary stone disease compared to a younger cohort.

Materials and Methods

A data base, including serum biochemical profiles, 24-hour urinalyses and standardized questionnaires, was retrospectively evaluated from more than 6,000 consecutive patients with urinary stone disease.

Results

Geriatric stone formers comprised 12% (721) of all stone patients. Two-thirds of these elderly patients had aberrant urinary values and 29% had isolated hypocitraturia compared to 17% in the younger group. Of geriatric stone forming patients 76% had recurrent urinary stones (mean 3.5 stone episodes), which was similar to the younger comparable group (77%, mean 3.3 stone episodes). The severity of urinary stone disease was similar between the 2 groups based on the need for urological intervention. Geriatric stone patients, in general, experienced the first stone episode later in life (after age 50 years) compared with younger patients. Elderly patients had an increased incidence of uric acid stones, but had a similar incidence of struvite calculi. Geriatric stone patients underwent parathyroid surgery more frequently (2.7 versus 0.7%). Geriatric stone forming patients rarely had renal failure.

Conclusions

The incidence, recurrence and severity of recurrent urinary stone disease were similar between geriatric and younger stone forming patients. Geriatric stone patients had an increased incidence of isolated hypocitraturia, uric acid calculi and previous parathyroidectomy. The geriatric stone population is not merely an extension of younger stone forming patients presenting at an older age. Rather, geriatric patients commonly experience the first symptomatic stone episode later in life.