[Treatment of patients with urinary tract obstruction and significant renal impairment]

Prognosis of renal function changes due to obstructive uropathy and prediction of remaining renal function after release of obstruction, have great impact on treatment we choose. There were analyzed various aspects of treatment and course of disease in 26 cases of obstructive uropathy with significant renal function impairment. It was found, that recovery of renal function after adequate kidney drainage was slower in cases of infravesical obstruction and vesicoureteral reflux in comparison with cases of ureteral obstruction. The renal function recovers more rapidly in cases with thicker parenchyma. Active surgical intervention and creation of adequate urine outflow from the obstructed kidney is method of choice at the beginning of treatment, even in cases with prolonged anamnesis of obstruction, significant renal failure and septic complications.

[Drinking water and urinary stones. Which drinking water and which modalities of diuresis?]

Urologists frequently advise a high fluid intake to their patients with calcium stones, but apart from this simple advice, they often have few convincing arguments. This article describes the various types of drinking water available in France (mineral water, spring water, tap water), the legislation concerning drinking water, and the ions that must be taken into account for long-term forced diuresis. After studying their composition and adapting the dietary advice (particularly concerning dairy foods) to this ionic composition, various types of water can be advised to patients, including tap water, most types of spring water, but not all mineral waters.

Asymptomatic hyperuricemia: to treat or not to treat

Treatment of asymptomatic hyperuricemia is not necessary in most patients, unless perhaps they have very high levels of uric acid or are otherwise at risk of complications, such as those with a personal or strong family history of gout, urolithiasis, or uric acid nephropathy.

Laser lithotripsy

PURPOSE OF REVIEW

All literature related to laser lithotripsy published within the past year was reviewed. Salient articles have been reviewed and grouped according to safety issues, efficacy, comparison studies, biliary applications or future directions.

RECENT FINDINGS

There is no evidence of renal deterioration after holmium:yttrium-aluminium-garnet lithotripsy. Laser-related complications occur in less than 1%. Stone-free rates from holmium:yttrium-aluminium-garnet lithotripsy are greater than 90% for ureteral calculi, and 67-84% for renal calculi. This method of lithotripsy is effective for ureteral and renal calculi in morbidly obese patients who are not suitable candidates for shock-wave lithotripsy or percutaneous nephrolithotomy. Holmium:yttrium-aluminium-garnet lithotripsy is more effective than pneumatic lithotripsy for ureteral calculi, but no more effective than shock-wave lithotripsy (Dornier HM-3) for distal ureteral calculi. Holmium:yttrium-aluminium-garnet lithotripsy of biliary calculi is uniformly effective. Preliminary data showed the erbium:yttrium-aluminium-garnet laser to be more efficient than holmium:yttrium-aluminium-garnet energy, but current erbium:yttrium-aluminium-garnet fibers are impractical.

SUMMARY

The holmium:yttrium-aluminium-garnet laser is safe and effective. It is the lithotrite of choice for endoscopic ureteral and ureterorenoscopic lithotripsy.

Does fluid amount and choice influence urinary stone formation in persons with spinal cord injury?

OBJECTIVE

To examine the effects of fluid intake and beverage type on stone formation in persons with spinal cord injury (SCI).

DESIGN

A matched case-control study.

SETTING

A rehabilitation center within a university hospital.

PATIENTS

Forty-one patients with SCI who were diagnosed with urinary stones between 1992 and 1998 (stone cases) and 171 age- and duration-matched controls were interviewed by telephone.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Urinary stones.

RESULTS

Stone cases were more likely than controls to be white, to be current smokers, to be users of indwelling catheterization, and to have a lower body mass index (kg/m(2)), worse renal function, and higher urine specific gravity (P<.10). In a multivariable model that adjusted simultaneously for other possible risk factors, the greater consumption of juice (>207mL/d) was associated with a 70% decreased risk (odds ratio=0.3; 90% confidence interval, 0.1-1.0). An interesting, but not significant (P=.15), increased risk for coffee consumption was observed. There was no association for total fluid intake.

CONCLUSION

Total fluid intake does not appear to determine stone occurrence; however, fluid type may influence stone formation in persons with SCI. Further study is required to verify these findings, thus possibly leading to an effective fluid regimen for stone prophylaxis.

Bone mineral density loss in patients with urolithiasis: a follow-up study

BACKGROUND

Recurrent calcium urolithiasis is often associated with disorders of calcium metabolism. The purpose of this investigation was to assess bone mineral content (BMC) and bone mineral density (BMD) over a period of 1 year in patients with urolithiasis and to determine the factors that could have influenced the changes in bone density during that period.

METHODS

The patient group comprised 34 men aged 41.2 plus minus 7.9 years with recurrent urolithiasis. A wide spectrum of biochemical measurements was performed. Bone mineral density (g/cm(2)), bone mineral content (BMC), and bone area (BA) were measured twice during a period of 1 year at the lumbar spine (L2-L4), femoral neck, Ward triangle, and trochanter, using dual energy absorptiometry. Patient results were compared to those obtained from 30 healthy male controls of a comparable age group.

RESULTS

Nine patients were hypercalciuric, while the majority of the remaining metabolic parameters were within the reference values. Bone mineral content and bone areas at all regions were lower in patients comparing to controls, but not significantly. The greatest annual reduction of BMD was noticed at Ward triangle (-5.70% in patients and -2.36% in controls), followed by femoral neck (-4.06% patients, -2.03% controls) and trochanter (-3.06% patients, -1.39% controls). There was no significant decrease of the BMD of the spine. Analyzing the influence of age, body mass index (BMI), metabolic parameters, and dietary calcium intake on the annual reduction of bone density, we found that age, hyperuricosuria, and calcium intake were significantly associated with bone loss in that time period.

CONCLUSIONS

Bone mass reduction in patients with urolithiasis over a 1-year period did not differ significantly from that in controls and was principally related to age, hyperuricosuria, and calcium dietary restriction but not to increased calcium excretion.

Effects of Tamm-Horsfall protein and albumin on the inhibition of free radicals

INTRODUCTION

Oxalate in urine can cause tubular cellular damage by the production of free radicals. Then, cell death and cellular debris may promote the retention of calcium oxalate crystals and finally the formation of stones. The two most abundant urinary proteins, Tamm-Horsfall protein (THP) and albumin, were tested for the effects of antioxidants.

MATERIALS AND METHODS

By using xanthine-xanthine oxidase reaction, purified THP and albumin were tested for the inhibitory effect. OD(295) was used as a spectrophotometric method to measure the production of uric acid during the reaction.

RESULTS AND CONCLUSIONS

Both proteins can inhibit the reaction of xanthine oxidase on xanthine, although the effect was decreased after enzymatic deglycosylation of sialic acid. Albumin has an IC(50) of 10.7 nM in native condition and 11.9 nM after deglycosylation, whereas THP has 69.6 nM in native condition and 102.0 nM in deglycosylated condition. The data indicates that THP and albumin have an antioxidant effect. Sialic acid in THP has partly an inhibitory effect and is associated with calcium oxalate formation. Studies have indicated that further investigation of the role of free radicals in the formation of urolithiasis and of sialic acid in protein function is needed.

Role of the diurnal variation of urinary pH and urinary calcium in urolithiasis: a study in outpatients

BACKGROUND

We previously reported that the urinary excretion of calcium and the diurnal variation of urinary pH were important for stone formation in hospitalized inpatients with hospital standard diet. Because almost all urinary stones are formed in outpatients with ambulatory free diet, it is essential to investigate these factors in outpatients.

METHODS

We examined the urinary excretion of calcium, oxalate, uric acid, phosphate and magnesium in 96 male outpatients and 142 male inpatients. We also studied the relationship between the stone composition and the diurnal variation of urinary pH in 32 male outpatients (five uric acid stones (UA), 13 pure calcium oxalate stones (CaOX) and 14 mixed calcium oxalate and calcium phosphate stones (CaOX-CaP)) and 53 male inpatients (nine UA, 15 CaOX and 29 CaOX-CaP).

RESULTS

There was a significant difference in the urinary excretion of calcium among outpatients with UA, CaOX and CaOX-CaP (133 +/- 96 vs 219 +/- 97 vs 268 +/- 102 mg per day, P < 0.05). In outpatients with UA, urinary pH was constantly low throughout the entire day. In contrast, outpatients with CaOX and those with CaOX-CaP had diurnal variation of urinary pH that was low in the early morning, followed by elevation in the daytime and was lowered in the night. The pHs in the early morning, afternoon and night were significantly higher in outpatients with CaOX-CaP than in those with CaOX.

CONCLUSION

The diurnal variation of urinary pH and the urinary calcium are important for stone formation.

Modulation of pain and hyperalgesia from the urinary tract by algogenic conditions of the reproductive organs in women

This study investigated the impact of algogenic conditions of the reproductive organs upon urinary pain perception in women. A 5-year survey was conducted among 69 fertile women with calculosis of one upper urinary tract via an ad-hoc questionnaire. At both retrospective (3 years) and prospective (2 years) investigation, dysmenorrheic women (D) reported more colics than non-dysmenorrheic women (ND) (P<0.001) and women with previous dysmenorrhea treated with estroprogestins (DH)(P<0.05). Pain thresholds (electrical stimulation) of the oblique musculature ipsilateral to the stone (L1, site of referred hyperalgesia from upper urinary tract) were lower in D than in ND (P<0.01) and DH (P<0.05). Calculosis women with asymptomatic endometriosis / ovarian cysts also reported more colics (6-month prospective study) and greater threshold lowering (P<0.05) than women with calculosis alone. The results show enhancement of urinary pain / hyperalgesia by both manifest and latent algogenic conditions of the female reproductive organs. This enhancement could derive from neuronal sensitization in spinal segments of common projection of the two visceral districts (T10-L1).

Correlation of unilateral urolithiasis with sleep posture

PURPOSE

Recurrent stone formers commonly present with calculi on the same side and the etiology of recurrent unilateral urolithiasis is unclear. Despite comprehensive metabolic evaluations, many patients will not be readily categorized into a treatable group. Data from the literature support that sleep posture may result in alterations of renal hemodynamics. We investigate the correlation of sleep posture with unilateral urinary stone formation.

MATERIALS AND METHODS

A prospective study of 110 patients with recurrent unilateral nephrolithiasis was conducted. A questionnaire was used to evaluate patient sleep posture. Right or left side down and rotisserie-like sleep postures were defined. The side of stone formation was correlated with sleep posture using chi-square test.

RESULTS

Of the patients 93 slept consistently with 1 side in a dependent position and the side of stone was identical to the dependent sleep side in 76% (p = 0.008). The positive predictive values of right and left side down sleep posture for formation of ipsilateral calculi were 82% and 70%, respectively.

CONCLUSIONS

Although the exact pathophysiology of the association between sleep posture and recurrent unilateral stone disease remains to be elucidated, sleep posture may alter renal hemodynamics during sleep and promote stone formation. This observation needs further investigation and should be factored into the evaluation and prevention of unilateral urinary stone disease.

Rethinking the role of urinary magnesium in calcium urolithiasis

BACKGROUND AND PURPOSE

The role of magnesium in urinary stone formation remains undefined. In vivo, magnesium inhibits stone formation in hyperoxaluric rats, and small clinical studies suggest a protective effect of magnesium supplementation in calcium oxalate stone formers. We performed a retrospective review of more than 7,000 stone patients to see if there is a relation between urinary magnesium and other stone risk variable constituents.

MATERIALS AND METHODS

A national database of stone formers categorized by residential ZIP code was queried, and, using strict inclusion criteria, 2,147 patients having pure calcium oxalate stones were identified. There were 1,912 (89%) eumagnesuric (43-246 mg/24 hours) and 235 (11%) hypomagnesuric (<43 mg/24 hours) patients.

RESULTS

Patients with decreased urinary magnesium excretion had significantly less daily urine excretion of citrate, calcium, oxalate, uric acid, and sodium than the eumagnesuric group (p < 0.0001). Stone recurrence was slightly more common in the hypomagnesuric group, although the difference was not statistically significant. The percentage of patients voiding <1 L of urine per day was significantly higher in the hypomagnesuric group. In the eumagnesuric group, males outnumbered females 2:1, whereas hypomagnesuric patients showed a female predominance of 1.4:1.

CONCLUSION

The beneficial effects of urinary magnesium on stone formation may be less than previously reported. The role of oral magnesium supplementation and the subsequent increase in urinary magnesium in calcium urinary stone formation remains unknown. Our data suggest that its effect on or interaction with citrate may be influential on urinary citrate concentrations. If magnesium has a protective effect, it may work through pathways that enhance citrate excretion.

[Transitory intrathoracic and -abdominal pressure elevation in the history of 64 patients with normal pressure glaucoma]

BACKGROUND

As one pathogenetic factor in normal-tension glaucoma an individually elevated sensitivity of lamina cribrosa regarding intraocular pressure fluctuations is postulated. Aim of this study was to evaluate patients with normal-tension glaucoma for the exposure to potential, clinically undetected transient elevations of intraocular tension due to increased intrathoracic and -abdominal pressure.

PATIENTS AND METHODS

A survey of 64 patients of the "Erlanger Glaucoma registry" with normal-tension glaucoma (NTG) and 64 patients with primary open angle glaucoma (pOAG) as control group were performed with regard to activities respectively diseases causing intrathoracic or -abdominal pressure elevation (1. weight lifting, 2. playing high resistance wind instruments, 3. chronic asthma/cough, 4. obstruction of the urinary system, 5. constipation). Both groups were matched regarding age (median: 61 years), sex (24 male, 40 female), visual field defects (mean defect: NTG 4.4; pOAG 4.7), visual acuity (median 1.0 +/- 0.2) and systemic diseases (diabetes mellitus, hypertension, cardiac disease).

RESULTS

Among patients with NTG there were 45% (29/64 patients) with activities respectively diseases causing intrathoracic or intraabdominal pressure elevation in their medical history compared to 11% (7/64) among patients with pOAG. Male patients with normal-tension glaucoma showed with 62% the highest frequency of such activities (among them 4/24 high resistance wind instrument playing, 5/24 urinary system obstructions, 4/24 long time weight lifting). Female patients with normal-tension glaucoma most frequently presented with a history of weight lifting (11/40).

CONCLUSION

Patients with glaucomatous optic nerve atrophy without evident intraocular pressure elevation compared to patients with pOWG more frequently report activities or diseases causing intrathoracic/-abdominal pressure elevation in their medical history. This may suggest an additional pathomechanism in normal-tension glaucoma. Therefore patients may be adviced on these potential risk factors.

[Effects of impaired urodynamics and contractile function of the upper urinary tract on elimination of stone fragments after extracorporeal lithotripsy]

The authors analyze effects of amplitude, tone and frequency of ureteral contractions on elimination of stones fragmented after extracorporeal shock-wave lithotripsy (ECSWL) in 30 patients with concrements in the kidneys and ureters. Before ECSWL the patients had indications for renal pelvis cathetarization. The measurements were made with multichannel impedance ureterography. According to initial dilatation of the upper urinary tracts (UUT), the patients were divided into 3 groups. It is shown that urodynamic UUT disorders determine effectiveness of ECSWL in urolithiasis patients: the greater is the dilatation the more probable are unsatisfactory results of ECSWL. Ureteral contractile activity is essential for rehabilitation in early postoperative period after ECSWL in patients with unrevealed UUT dilation: high amplitude of ureteral contractions in low tone is good for the fragments elimination, while high tone may result to the fragments ejection into the kidney. Low contractility may contribute to development of stone path. In patients with pronounced UUT dilation ureteral contractility is less important for ECSWL effectiveness than the wall tone and retrograde ureteral peristaltic movements. ECSWL results are better in patients with low tone of UUT wall. High UUT tone, especially in combination with retrograde peristaltic ureteral contractions registered prior to ECSWL indicates high probability of residual stones and additional fragmentation procedures irrespective of initial UUT dilation.

CT for the evaluation of flank pain

Unenhanced helical CT allows rapid and accurate determination of whether a stone is present anywhere in the urinary tract. There is a learning curve for both radiologist and urologist, but a number of signs are highly predictive of stone. Helical CT scans should always be accompanied by a "scoutogram" to convey an idea of what the stone might look like. The scan requires no contrast medium and takes only 5 to 10 minutes of imaging time, making it cost effective. It behooves both urologists and radiologists to familiarize themselves with the techniques for reading these scans.

Fibronectin as a potent inhibitor of calcium oxalate urolithiasis

PURPOSE

Fibronectin (230 kD.) is a multifunctional alpha2-glycoprotein distributed throughout the extracellular matrix and body fluids. Many investigators have demonstrated that fibronectin, because of its cell adhesive action, is related to biological processes such as morphogenesis, wound healing and metastasis. Recent studies have shown that a variety of molecules, including fibronectin, inhibit endocytosis of calcium oxalate crystals in vitro. We investigated other roles of fibronectin in calcium oxalate stone formation.

MATERIALS AND METHODS

Immunoblotting of the crystal surface binding substance obtained from pooled healthy male urine samples was used to analyze whether fibronectin was adsorbed onto the surface of calcium oxalate crystals. To clarify the relationship between fibronectin and calcium oxalate crystals, we performed 6 experiments. Experiment 1 was immunohistochemical examination of fibronectin expression in stone forming rat model kidneys, and experiment 2 examined the fibronectin content of stone forming rat kidney models with the enzyme-linked immunosorbent assay. Experiment 3 was designed to determine fibronectin content of Madin-Darby canine kidney (MDCK) cells stimulated by addition of calcium oxalate crystals and experiment 4 identified the inhibitory effect of fibronectin on calcium oxalate crystal growth by the seed crystal method. For experiment 5 we used an aggregometer system to clarify the inhibitory effect of fibronectin on calcium oxalate crystal aggregation and experiment 6 examined the inhibitory effect of fibronectin on the adhesion of calcium oxalate crystals to MDCK cells.

RESULTS

In the crystal surface binding substance immunoreactive bands at 230 kD., which correspond to the molecular weight of fibronectin, were detected by Western blot analysis. In stone forming rat kidneys strong expression of fibronectin was found on the renal tubules to which the crystals were attached. The fibronectin content of these kidneys was significantly greater than that of kidneys without calcium oxalate crystals. The fibronectin content of MDCK cells tended to increase in proportion to the concentration of calcium oxalate crystals added to the culture medium. The growth inhibition assay showed that the inhibitory effect of fibronectin on calcium oxalate crystal growth was small in relation to the quantity of fibronectin excreted. However, fibronectin had inhibitory effects on calcium oxalate crystal aggregation and adhesion of the crystals to MDCK cells.

CONCLUSIONS

Fibronectin secretion can be stimulated by calcium oxalate crystals, and this protein, which is excreted from the tubular cells, may inhibit calcium oxalate crystal aggregation and attachment to cells.

Cost-effective emergency diagnosis plan for urinary stone patients presenting with ureteric colic

OBJECTIVE

To develop a cost-effective plan for the accurate diagnosis of urinary stone patients presenting with ureteric colic based on an assortment of investigations which are less invasive and more economical than intravenous urography (IVU).

PATIENTS AND METHODS

143 consecutive emergency patients presenting with ureteric colic were admitted to hospital and prospectively studied by history recording, physical examination, laboratory tests and imaging procedures according to a preset format. Significant association of the final diagnosis of urinary stones (which was made by actual stone retrieval) with various diagnosis variables obtained from the results of investigation (including IVU) was statistically studied using bivariate correlation and multivariate logistic regression analysis. Algorithms for reaching an accurate diagnosis of urinary tract stones were formulated using the most significant diagnostic variables and the accuracy of each of those plans was compared with that of emergency IVU.

RESULTS

18 patients were excluded for various reasons. Of the remaining 125 patients 82 (66%) were confirmed as having urinary stones. A positive IVU had the strongest correlation with the final diagnosis of urinary tract stones. Other findings associated with eventual stone retrieval in a descending order of significance were: calcular sonographic features; radio-opacities on a plain abdominal film of the kidney, ureter and bladder (KUB), and microhaematuria. Based on these findings two algorithms could be formulated to reach as accurate a diagnosis as possible. Algorithm A in which an initial ultrasound is mandatory had a sensitivity of 89%, a specificity of 88% and an overall accuracy of 88% for urinary stone detection compared with 91, 77, and 86%, respectively, for algorithm B in which ultrasonography was employed selectively after initial KUB and urinalysis for microhaematuria. This compares with 94, 79, and 89%, respectively, for IVU.

CONCLUSION

Both plans are viable alternatives which could replace routine emergency IVU.

[Functional state of upper urinary tract in urgent extracorporeal lithotripsy]

Seven patients have undergone urgent extracorporeal lithotripsy (UEL) for renal colics. 3 patients were cured. Before UEL they had insignificant defects of urodynamics and ureteral contraction. 3 patients with initial dilation of the upper urinary tracts > 2 cm and reflux ureteral motility, residual concrements eliminated spontaneously or after additional UEL procedures or combined treatment. One female with initial pelvic and uretral dilation and disturbed motility of the upper urinary tracts was treated for 6 months. 1-2.5-year follow-up detected neither concrements nor marked dilation of the calyceropelvic system. Patients with renal colics have more pronounced local defects of contraction rhythm and activity, peristaltic direction. Peristaltic disorders in the upper urinary tracts in patients with renal colics are local and may be related to acute occlusion and neuroreflex effects. This explains why UEL produces good results in renal colics, especially in patients with minimal defects of urodynamics. Complicated course after UEL early after the operation occurred in patients with dilated upper urinary tracts, high contraction amplitude registered by high tonicity of the ureteral wall and the presence of retrograde peristaltic waves.

[Effects of mineral water TIB-2 on metabolic processes in urolithiasis patients]

Natural low-mineralized hydrocarbonate-calcium-magnesium mineral water (total mineralization 2 g/l) in bottles has been examined for therapeutic effects on metabolism in urolithiasis patients. The complex of biochemical blood and urine indices indicative of the renal function and concentration of lithogenic components was studied in 52 patients (age 23-68 years, 23 males and 29 females). Ten of them had nephrostoma. All the patients have undergone extracorporeal lithotripsy or other operations for renal or ureteric calculi. In nephrostoma patients urine samples were obtained both from nephrostoma and urinary bladder. The tests were made before the treatment and on the treatment day 3-5 and 10-12. TIB-2 mineral water was taken 3 times a day in a dose 200 ml 30-45 minutes before meal. The data were statistically processed. From the data obtained it was concluded that mineral water TIB-2 normalizes azotemia and clearance of endogenic creatinine, plasma values of calcium and uric acid, enhances urinary elimination of uric acid and calcium oxalate microcrystals that is TIB-2 improves metabolism of lithogenic substances and ions. Indications to drinking mineral water TIB-2 for urological patients are formulated.

Mutation induction by mechanical irritation caused by uracil-induced urolithiasis in Big Blue rats

Some chronic mechanical irritations induce cancers, and it is speculated that mutations are induced by increased rate of cell proliferation caused by the irritation. In this study, it was investigated using chronic mechanical irritation to urothelium caused by urolithiasis, whether mutations are really induced by such cell proliferation or not. Male rats transgenic for lacI (Big Blue(R) rats), in which lacI mutations accumulated in tissue can be measured, were fed 3% uracil, a component of RNA, to induce urolithiasis associated with papillomatosis, and eventually with bladder cancers. The frequency of independent mutations in the bladders of the treated rats showed 3-5 fold increases at weeks 10, 20, and 51 (P=0.01 at week 51) while the frequency was not elevated at week 2. The mutation frequencies in the control bladders ranged from 3 to 9x10(-6). In both groups, G to A transitions at CpG sites, indicative of spontaneous mutations, constituted the most prevalent mutations. Mechanical irritation caused by uracil was shown to induce a 3-5 fold increase of mutations, possibly through an elevation of spontaneous mutations by vigorous cell proliferation.

Calculus artifact. A challenge in urinary cytology

OBJECTIVE

To retrospectively review calculus artifact and compare it with instrument artifact and papillary transitional cell carcinoma (TCC).

STUDY DESIGN

Voided urine specimens from patients with calculi (65), TCC (low grade, 10, high grade, 34) and history of prior instrumentation (12) were studied.

RESULTS

Nineteen specimens of calculus artifact had unremarkable cytology. Forty-six specimens had abnormal single cells or papillary clusters and cell balls or a mixture of both. The papillary groups had smooth as well as irregular borders, a cytoplasmic collar and cells with occasional cytoplasmic vacuoles, slightly increased nuclear/cytoplasmic (N/C) ratio and inconspicuous nucleoli. Squamous preponderance and birefringent crystals were seen. In instrumentation artifact, papillary clusters or three-dimensional cell balls had smooth borders, cytoplasmic collars, an occasional cytoplasmic vacuole, normal N/C ratio, regular nuclear membrane and finely granular nuclear chromatin. In TCC, papillary clusters with loss of polarity and irregular borders were present in both grades but were predominant in low grade TCC. No cytoplasmic collar was noted. In high grade TCC, single cells and nuclear alterations were more pronounced, with increased N/C ratio, hyperchromasia, coarse chromatin, irregular nuclear envelopes, prominent nucleoli and rare mitosis.

CONCLUSION

Calculus artifact can produce papillary clusters masquerading as papillary TCC. Unlike instrument artifact, there may be significant nuclear atypia, which could be reversible. To avoid diagnostic pitfalls, further investigation is suggested after removal of calculus.

Helical CT of urinary tract stones. Epidemiology, origin, pathophysiology, diagnosis, and management

Urolithiasis is a common medical problem. The diagnosis of this entity in the setting of acute flank pain presents an interesting challenge to the radiologist. Unenhanced helical CT has recently entered the fray and has quickly become the imaging study of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. The nature and origin of ureteral stones and the pathophysiology of ureteral obstruction provide a basis for understanding the imaging findings in these patients.

The impact of contemporary bladder management techniques on struvite calculi associated with spinal cord injury

OBJECTIVE

To evaluate the incidence, risk factors and complications of upper tract struvite calculi, often associated with spinal cord injury (SCI), as such patients have a high incidence of urinary infection complicating their neurogenic voiding dysfunction, by reviewing a large population of patients with SCI in whom modern techniques of bladder management were used.

PATIENTS AND METHODS

Between 1982 and 1996, 1669 patients with SCI were admitted to our institution; 1359 of these patients sustained their injuries during the study period. During this time, their bladder management was based on urodynamic and imaging criteria, using techniques such as early intermittent catheterization, sphincterotomy and bladder augmentation where possible to create a catheter-free, low-pressure reservoir. All instances of upper tract struvite calculi in this population were documented. Risk factors for stone development, presentation and complications, management and recurrence rates were assessed.

RESULTS

Over the 15 years, 58 patients (3.5% of the SCI population) were treated for a total of 144 episodes of struvite calculi. The incidence of stones in those injured since 1982 was 1. 5%; 67% of these patients had complete spinal cord lesions, 54% had lesions of the cervical cord and 53% developed their first stone >10 years after injury. Only 22% presented within 2 years of injury. The group of patients developing stones had a significantly higher incidence of indwelling catheters (49%), bladder stones (52%) and vesico-ureteric reflux (28%) than those who were stone-free. The development of recurrent urinary tract infections was the most common mode of presentation. The stone-free rate after treatment was 87%. Normal renal function was preserved in 72% of patients.

CONCLUSIONS

In a large population of patients with SCI managed using contemporary bladder techniques the incidence of upper tract calculi was 3.5%; 30% of these stones were complete or partial staghorns. Those patients with complete cord lesions, permanent indwelling catheters and vesico-ureteric reflux were at the highest risk. Stone clearance was 87% and recurrent stones occurred in 69% of patients. Struvite renal calculi continue to be a significant problem in the spinal cord injury population.