Imaging characteristics of indinavir calculi

PURPOSE: Indinavir sulfate is an effective protease inhibitor of the human immunodeficiency virus type 1. Use is associated with a significant incidence of crystallization and stone formation in the urinary tract, and these calculi are not visible on plain radiographs. Previously all urinary stones, including uric acid and matrix, were believed to be radiodense on computerized tomography (CT). We conducted a retrospective study to evaluate the radiographic appearance of indinavir calculi. MATERIALS AND METHODS: Retrospective chart review of 36 patients taking indinavir sulfate and presenting with renal colic was performed with attention to presentation, urinalysis, radiographic evaluation and management. Specifically, imaging characteristics on CT were addressed. RESULTS: All patients complained of ipsilateral flank pain and 35 had nausea and/or vomiting. Of 30 patients with dysuria or urgency the majority had hematuria, and most had pyuria and/or proteinuria. No stones were visualized on abdominal radiography. Diagnosis was confirmed on 1 of 13 excretory urograms and 4 of 11 renal ultrasounds. None of 12 CT scans was diagnostic of renal lithiasis. CONCLUSIONS: Indinavir sulfate is a protease inhibitor with poor solubility and significant urinary excretion. Crystallization and stone formation are demonstrated in as many as 20% of patients taking the medication. Most patients present with flank pain, nausea or vomiting and hematuria. Previously CT was thought to identify all urinary calculi with clarity but it cannot reliably confirm the presence of indinavir calculi.     

Clinical presentation and metabolic features of overt and occult urolithiasis

Although pediatricians are frequently confronted with patients presenting urolithiasis symptoms without obvious stones, the syndrome of occult urolithiasis may be still viewed with some skepticism. We have compared the clinical and metabolic features of 197 children with obvious calculi, 189 with microcalculi (diameter ≤3 mm based on renal sonography), and 114 with symptoms of urolithiasis and normal renal sonography findings. Only microcalculi and normal sonography subjects with a urinary abnormality potentially leading to urolithiasis were included in the study. Age at presentation increased significantly (p = 0.0001) in the groups in the order normal sonography to microcalculi to calculi groups. There was no significant difference among the three groups in terms of family history of urolithiasis, gender distribution, and degree of hypercalciuria, hyperuricosuria, hyperoxaluria, or hypocitraturia. The average frequency of pain attacks of patients with recurrent abdominal pain (RAP) ranged from 3.6 to 4.6 days of pain per month among the three groups, which is four to ninefold lower than that reported for children with functional or organic gastrointestinal RAP. The consistency of many clinical and urinary metabolic characteristics indicates a common underlying disorder in overt and occult urolithiasis. The increase of age at presentation from the normal sonography to microcalculi and calculi groups may reflect progressive crystal accretion leading ultimately to overt stone formation.     

Flexible ureteroscopy and holmium laser lithotripsy for treatment of upper urinary tract calculi in patients with autosomal dominant polycystic kidney disease

The objective of the study was to investigate the safety and efficacy of flexible ureteroscopy and holmium laser lithotripsy for the management of patients with autosomal dominant polycystic kidney disease (ADPKD) and associated nephrolithiasis. Between 2005 and 2010, flexible ureteroscopic stone treatment was attempted in 13 patients with ADPKD. Two patients had bilateral renal stones. Most of the stones were located in the renal pelvis and/or calices with a stone size 1.7 cm in the largest diameter. The success rate and morbidity and complications were recorded. A total of 45 intrarenal calculi with a mean stone size of 5.6 mm (range 3–17) were identified. The mean number of stones per patients was 3.2 (range 2–5). The mean number of primary procedures was 1.2 (range 1–2). The overall stone-free rates after one and two procedures were 84.5 and 92.3%, respectively. Complications occurred in three procedures and consisted of low-grade fever in one procedure, flank pain in another procedure and stent pain in another procedure. No patient died. Flexible ureteroscopy with holmium laser lithotripsy is a safe and effective method for the treatment of patients with ADPKD and associated nephrolithiasis.     

Risk factors for nephrolithiasis in children

OBJECTIVE: The aim of this study is to evaluate the clinical outcome in children with urinary calculi, to detect risk factors for nephrolithiasis in childhood. MATERIAL AND METHODS: This retrospective study comprised 62 pediatric nephrolithiasis patients who have come for routine follow-up visits between the dates of January 2002-August 2006 (48% girls and 52% boys). RESULTS: The mean age of the patients was 8.8 +/- 4.5 years (1-16 years). Hypercalciuria was found in 25 (40%) patients. The mean urinary calcium excretion for hypercalciuric patients was 5.7 +/- 1.2 mg/kg (4.8 mg/kg per day). In our hypercalciuric patients 15 (60%) children had abdominal or flank pain, seven (28%) patients macroscopic hematuria and three (12%) dysuria. Hypocitraturia is the second important risk factor for nephrolithiasis. Urinary calcium excretion showed a positive correlation with the stone size (r = 0.482, P = 0.043). A positive correlation was found between recurrent urinary tract infection (UTI) and hypercalciuria (r = 0.528, P = 0.017). Urinary citrate excretion showed a negative correlation with recurrent UTI (r = -0.503, P = 0.024). Hyperuricaciduria, hyperoxaluria were found to have no effect on the stone size and UTI of the patients. Stones were disintegrated with ESWL in two patients, endoscopic interventions were used in one patient and two underwent an open surgical procedure. CONCLUSION: All children with nephrolithiasis should have a metabolic screen. Children with a positive family history and consanguinity should be followed carefully with respect to metabolic abnormalities.     

Idiopathic hypercalciuria and hyperuricosuria: family prevalence of nephrolithiasis

We studied the prevalence of a history of nephrolithiasis in first- and second-degree relatives of 74 children with hypercalciuria (HC), 61 with hyperuricosuria (HU), and 41 with HC plus HU, and in a control population of 261 children with different diseases. Family history of nephrolithiasis was found in 69% of HC, 75% of HU, 78% of HC plus HU, and 22% of control patients. The prevalence was not different among HC, HU, and HC plus HU groups, but was significantly higher in each study group than the control group (P=0.0001). Body mass index >95th percentile was found in only 4.7% of the patients with HC or HC plus HU. Calculi (>3 mm in diameter) were present in 8.9% of the patients with a family history of nephrolithiasis and in 9.4% of those with no family history (P=0.85). Microcalculi (<3 mm in diameter) were found by sonography in 56.6% of the patients with and in 53.3% of those without a family history of nephrolithiasis (P=0.83). Children with HC and/or HU have a strong familial prevalence of nephrolithiasis. Obesity does not seem to affect the association of familial nephrolithiasis and hypercalciuria in children. The presence of nephrolithiasis in families of children with HC and/or HU is not associated with a higher rate of formation of calculi or microcalculi. Received: 4 August 1999 / Revised: 18 January 2000 / Accepted: 28 January 2000     

Unenhanced helical computed tomography in the evaluation of acute flank pain

OBJECTIVE: The diagnostic value of unenhanced helical computed tomography (CT) for the evaluation of acute flank pain is investigated in a prospective study. PATIENTS AND METHODS: In 125 patients aged 18-86 years, we performed unenhanced helical CT in addition to abdominal plain film, abdominal ultrasound and urinalysis as a diagnostic measure for acute flank pain. Ureteral calculi were confirmed or, respectively, excluded by retrograde ureteropyelography in 80 cases. In the other cases, diagnosis was verified by clinical course and/or stone asservation. RESULTS: In 91 of 125 patients the flank pain was caused by a ureteral calculus. In 67 of 91 patients with urolithiasis, stones could be collected for analysis. Helical CT was able to precisely identify 90 ureteral calculi. Abdominal plain films led to 8 false-positive and 48 false-negative findings. Thus, sensitivity of plain radiography, ultrasound and urinalysis was 47, 11 and 84% with a specificity 76, 97 and 32%, respectively. CONCLUSIONS: Unenhanced helical CT reaches a distinctively increased diagnostic value (sensitivity 99%, specificity 97%) in the evaluation of acute flank pain as compared to plain radiography, ultrasound and urinalysis.     

Calyceal microlithiasis in children: report on 196 cases

Recognition of children at greatest risk for urolithiasis may allow early detection or prevention of stone formation. We report clinical data from 196 children aged 0.9–15.9 years in whom renal ultrasound examination revealed hyperechogenic spots in renal calyces less than 3 mm in diameter. We called this finding “calyceal microlithiasis” (CM). There was a history of urolithiasis in 70.4% of patients in at least one first- or second-degree relative. Presenting symptoms were recurrent abdominal pain, dysuria, and hematuria, occurring alone or in combination. Hematuria was the presenting symptom in 41% of patients and was the only urinary finding in more than one-third. Hypercalciuria was present in about one-third and hyperuricuria in one-fifth of the patients. Of 29 patients who were followed for at least 2 years, 9 developed calculi 4–7 mm in diameter. CM possibly represents the first step in calculus formation. The finding of CM might explain a number of symptoms and signs that are often mild and non-specific, thus reducing invasive diagnostic procedures. Received November 26, 1996; received in revised form August 7, 1997; accepted November 5, 1997     

Treatment outcomes of semirigid ureterorenoscopy and intracorporeal lithotripsy in pregnant women with obstructive ureteral calculi

The purpose of the study is to evaluate the outcomes of semirigid ureterorenoscopy and intracorporeal lithotripsy as a definitive treatment in pregnant women with obstructive ureteral calculi. A retrospective analysis was performed of 16 pregnant patients referred to gynecology department with ureteral obstruction from 2007 to 2009. The mean age was 25 years, and mean gestation period was 30 weeks. Of the 16 patients; 50% had fever, 100% flank pain, 56% dysuria, 25% gross hematuria, 50% positive urine culture, and 75% pyuria and microscopic hematuria. Abdominal ultrasonography was the principle diagnostic test used. The mean stone size was 9.45 mm. Eleven of the 16 patients, 54% had stones located in the distal ureter and 46% proximal ureter. The stones were fragmented using a swiss pneumatic lithoclast through 9.5 F semirigid ureteroscope by 0.035 mm safety guidewire with the patient under general anesthesia. Eleven patients had obstruction due to the ureteral calculi. Eight of 11 patients had complete fragmentation of the calculi by ureteroscopy as a primary treatment. Push-back was performed in the other three patients. By applying Dj catheter, and performing eswl after giving birth, the patient became stone-free. Dj catheter was applied peroperative to all 16 patients. No complications were recorded, and all patients completed the full term of pregnancy. The results of our study have shown that semirigid ureteroscopy to diagnose ureteral calculi and treat them with intracorporeal pneumatic lithotripsy and ureteral stent insertion, as indicated, is the most efficient and definitive treatment modality in pregnant women.     

Influence of body size on urinary stone composition in men and women

A larger body size has been shown to be associated with increased excretion of urinary lithogenic solutes, and an increased risk of nephrolithiasis has been reported in overweight patients. However, the type of stones produced in these subjects has not been ascertained. Based on a large series of calculi, we examined the relationship between body size and the composition of stones, in order to assess which type of stone is predominantly favoured by overweight. Among 18,845 consecutive calculi referred to our laboratory, 2,100 came from adults with recorded body height and weight. Excluding calculi from patients with diabetes mellitus, as well as struvite and cystine stones, the study material consisted of 1,931 calcium or uric acid calculi. All calculi were analysed by infrared spectroscopy and categorized according to their main component. Body mass index (BMI) values were stratified as normal BMI (<25 kg/m²), overweight (BMI 25–29.9) or obese (BMI≥30). Overall, 27.1% of male and 19.6% of female stone formers were overweight, and 8.4 and 13.5% were obese, respectively. In males, the proportion of calcium stones was lower in overweight and obese groups than in normal BMI group, whereas the proportion of uric acid stones gradually increased with BMI, from 7.1% in normal BMI to 28.7% in obese subjects (P<0.0001). The same was true in females, with a proportion of uric acid stones rising from 6.1% in normal BMI to 17.1% in obese patients (P=0.003). In addition, the proportion of uric acid stones markedly rose with age in both genders (P<0.0001). The average BMI value was significantly higher in uric acid stone formers aged <60 years than in all other groups, whereas it did not differ from other groups in those aged ≥60 years. Stepwise regression analysis identified BMI and age as significant, independent covariates associated with the risk of uric acid stones. Our data provide evidence that overweight is associated with a high proportion of uric acid stones in patients less than 60 years of age, whereas beyond this limit, advancing age is the main risk factor.     

Clinical studies on childhood urolithiasis during the past 22 years

We have studied retrospectively 68 children who presented with urolithiasis between 1965 and 1986. Male to female ratio was 1.83 to 1 and the mean age was 9.5 years. Fifty four children (79%) had calculi in the upper urinary tract, 9 (13%) had in the lower, and 4 (6%) had calculi both in the upper and lower urinary tract. The most common presenting symptoms were gross hematuria (53%) and abdominal or flank pain (38%). Predisposing factors could be found only in 21 children (31%). Twenty four of the 68 patients (35%) had open surgery and 16 patients (24%) passed their stones spontaneously. Twenty one stones were analyzed by infrared spectroscopy. Infectious stone was more frequent than in adult cases. Among children five years old and younger, infectious stone was the most frequent. Among children over five years old, the number of idiopathic calcium stone has been on the increase with the years.     

PERCUTANEOUS NEPHROLITHOTOMY IN THE PEDIATRIC POPULATION

PURPOSE: Percutaneous nephrolithotomy is an established technique used in children with renal calculi. We review our experience with percutaneous nephrolithotomy for treating nephrolithiasis in childhood. MATERIALS AND METHODS: We retrospectively reviewed the records of children who underwent percutaneous nephrolithotomy procedures for renal calculi from 1985 to 1996. Antegrade percutaneous access was obtained in all patients and the tract was dilated to 24F. Grasper forceps, ultrasound and/or electrohydraulic lithotripsy was used to remove and disintegrate stones. In all patients a nephrostomy tube was placed intraoperatively, and a plain abdominal x-ray and nephrostogram were done postoperatively. The nephrostomy tube was removed after ensuring free drainage down the ureter and no untoward effects from clamping. Complete anatomical and metabolic evaluation was performed in all cases. Patients were followed 2 to 6 weeks, and 3 and 6 months postoperatively with a plain abdominal x-ray and excretory urography or renal ultrasound. RESULTS: In 5 boys and 3 girls (9 renal units) 4 to 11 years old (mean age 6.4) a total of 10 percutaneous nephrolithotomy procedures were performed. At presentation 6 children had flank and/or abdominal pain, 5 gross hematuria and 3 urinary tract infection. Three patients had associated metabolic abnormalities. One patient with a staghorn calculus had hydronephrosis and multiple infundibular stenoses. No underlying urological anatomical abnormalities were noted in the remaining cases. Four renal units that were obstructed at presentation required initial nephrostomy tube insertion. Average operative time was 131.8 minutes (range 58 to 240). An 87.5% stone-free rate was achieved using percutaneous nephrolithotomy monotherapy. Percutaneous nephrolithotomy was not successful for eradicating a staghorn stone in 1 patient. Hypothermia developed in 2 patients in whom operative time exceeded 150 minutes. No blood transfusions were required. CONCLUSIONS: Percutaneous nephrolithotomy is safe and effective in children, and should be considered a viable management option. However, staghorn calculi may require alternative management, particularly in the setting of underlying anatomical abnormalities. Children with renal calculi should undergo a complete anatomical and metabolic assessment with the institution of medical therapy, as appropriate.     

Factors affecting the success rate of extracorporeal shock wave lithotripsy for renal calculi in children

The aim of the study was to analyse factors affecting the success rate of extracorporeal shock wave lithotripsy (ESWL) in children with renal calculi. We performed a retrospective analysis reviewing records of 85 (40 female, 45 male) children (89 renal units) subjected to ESWL for treatment of renal calculi during 1990–2005 in our department. As 4 patients had bilateral calculi and 19 children (21 renal units) had renal stones at more than one different site, each location was analysed separately for convenience. The mean age of the patients was 10.3±4.6 (2–16) years. The stone-free rates for renal pelvis, lower, middle and upper caliceal calculi were 70, 62, 50 and 73%, respectively. A higher rate (33%) of insignificant fragments (≤4 mm) was noted for lower pole calculi. Increased stone diameter (P=0.0001) and burden (P=0.04) were found as the most significant factors that adversely affect the stone-free rate for pelvis renalis calculi, whereas an acutely oriented infundibulum and/or a long lower infundibulum (P=0.005) were unfavourable factors for clearance of lower caliceal stones. The stone-free rate in children with multiple calculi was 48%, while 29% of the renal units had retained fragments. ESWL is a good initial option for treatment of most of the renal calculi <2 cm except in the presence of unfavourable lower caliceal anatomy. Increased stone burden, multiple stones, staghorn calculi, narrow lower infundibulopelvic angle and long lower infundibulum are factors that adversely affect the clearance rate.     

Stepwise shock wave lithotripsy: Results of initial study for the treatment of urinary stones in childhood

Objective: To assess the effectiveness of stepwise extracorporeal shock wave lithotripsy in the treatment of upper urinary stones in childhood. Patients and methods: Between August 1998 and August 2003, 31 patients were treated for renal or ureteric stones. All treatments were performed with Dornier Compact Delta lithotripter. The number of shock wave was limited to maximum 3000 shock waves/session. The voltage was started at 10 kV and increased stepwise to 12.75 kV. Stone clearance was assessed at 3 months. The stone free state was defined as the absence of stone fragments. Results: Total 31 stones (24 renal and 7 ureteral stones) were treated. The age of the patients was median 8 (min–max: 0.8–12) years. The length of the stones was median 1 (min–max: 0.5–1.5) cm for renal stones and median 0.5 (min–max: 0.5–1) cm for ureteral stones. As an auxiliary procedure, open pyelolithotomy was required for 1 patient. The overall stone free rates for renal and ureter stones were 79% and 100%, respectively. Post-treatment insignificant hematuria was observed in all cases. Conclusion: Stepwise shock wave lithotripsy was an effective procedure for the treatment of urinary calculi in childhood.     

Robotic extended pyelolithotomy for complete staghorn calculus

Staghorn stones represent a therapeutic challenge to urologists. We present our experience with laparoscopic extended pyelolithotomy for treatment of staghorn and complex renal calculi in highly selected cases. This approach provides the principles of open surgery with the advantages of minimally invasive surgery. We describe our experience with robot-assisted extended pyelolithotomy for complex coralliform calculi. Since January 2007, robotic extended pyelolithotomy has been performed by transperitoneal approach in two patients with complete coralliform lithiasis (calculi average size 8 cm). One patient had history of percutaneous nephrolithotomy. Demographic and operative data were collected. All procedures were technically successful without need for open conversion. Mean estimated blood loss was 175 ml (range 50–300 ml), and mean operative time was 150 min (range 120–150 min). A perinephric drain was employed in one patient with duration of 5 days. Postoperative imaging confirmed complete stone clearance. Robotic extended pyelolithotomy is a feasible and reproducible procedure for removal of complete and partial staghorn calculi in selected patients with complex nephrolithiasis. This approach might limit the role of open surgery for these calculi, but further publications with more cases are necessary to further define its utility.     

Screening for kidney disease in children on World Kidney Day in Jalisco,Mexico

World Kidney Day (WKD) is intended to raise awareness and increase detection of chronic kidney disease (CKD), but most emphasis is placed on adults rather than children. We examined yield of screening for CKD and hypertension among poor children in Mexico. On WKD (2006, 2007), children (age < 18 years) without known CKD were invited to participate at two screening stations. We measured body mass index (BMI), blood pressure, and serum creatinine, and performed dipstick urinalysis. The Schwartz equation was used to estimate glomerular filtration rate (GFR; reduced GFR defined as < 60 ml/min per 1.73 m²). Proteinuria and hematuria were defined by a reading of ≥ 1+ protein or blood on dipstick. Hypertension was defined by gender, age, and height-specific norms. In total, 240 children were screened (mean age 8.9 ± 4.1 years; 44.2% male). Proteinuria and hematuria were detected in 38 (16.1%) and 41 (17.5%), respectively; 15% had BMI > 95th percentile for age. Reduced GFR was detected in four (1.7%) individuals. Systolic hypertension was more prevalent in younger children (age 0–8 years, 19.6%; age 9–13 years, 7.1%; age 14–17 years, 5.3%) suggesting a possible white-coat effect. Hematuria, proteinuria, hypertension and obesity were frequently detected among children in a community based screening program in Mexico. This form of screening might be useful in identifying children with CKD and hypertension in developing nations.     

Incidentally detected ureteral fibroepithelial polyps in children: is endoscopic treatment of them really necessary?

Objective

Fibroepithelial polyps (FEPs) are the most common benign lesions of the ureter. However, FEPs of the ureter accompanied by calculi are rare. In this study, we reviewed our experiences with five children having FEP associated with ureteral calculi to define more clearly this entity and its outcome following observation.

Materials and Methods

We identified five children who were intraoperatively found to have FEP associated with ureteral calculi during the period 2000–2008.

Results

The patients included four males and one female, and the average age of these patients was 6.4 years (range 4–9). The main symptoms were flank pain (five patients), hematuria (four patients), and dysuria (two patients). Radiographically, all patients showed complete ureteral obstruction due to distal ureter stone and hydronephrosis. Fibroepithelial polyps and stones were located left distal ureter in all children. These polyps were 1–2 cm, with a mean size of 1.5 cm. Stone sizes ranged from 5 to 13 mm (mean 8.8 mm). The stones were smashed into smaller fragments using a pneumatic lithotriptor, and the pieces were removed with forceps. After the lithotripsy, the polyps were grasped with biopsy forceps and punch biopsies were done. FEPs were diagnosed in all cases by postoperative histological examination. During the follow-up period of these patients, none of the FEPs displayed any growth or symptom.

Conclusions

Due to the potential complications during the ureteroscopic resection, our opinion is to observe the small FEPs without joint symptoms and hydronephrosis.     

Ceftriaxone associated nephrolithiasis: a prospective study in 284 children

Urinary tract calculi have been reported to account for between 1 in 1,000 and 1 in 7,600 hospital admissions in children in the USA. The annual incidence of urolithiasis in patients older than 10 years is 109 per 100,000 of the population in men and 36 per 100,000 of the population in women in Minnesota. The use of various medications is considered to be one of the etiologic factors of nephrolithiasis. Ceftriaxone is a widely used third-generation cephalosporin that is generally considered very safe, but complications such as biliary pseudolithiasis, and rarely, nephrolithiasis have been reported in children. There is limited information about urolithiasis as a side effect of ceftriaxone. The aim of this study was evaluation of the incidence of nephrolithiasis following ceftriaxone therapy in children. This quasi-experimental before and after study was conducted in Mofid Children’s Hospital between 2003 and 2005. All patients were treated with 75 mg/kg intravenous ceftriaxone. Diagnosis of pyelonephritis was based on standard criteria. The first renal ultrasonography was performed on the first or second day of admission and was repeated on the last day of treatment. We also evaluated complicated patients for the third time with renal ultrasonography 3 months after treatment. Stone-forming patients underwent metabolic kidney stone risk factor evaluation. We evaluated 284 patients with pyelonephritis, 185 girls and 99 boys. The first ultrasonography was normal in all of our patients. On the second ultrasonography renal stones were reported in 4 out of 284 cases (1.4% and CI = 0.96–1.83%). Underlying metabolic risk factors could not be identified in stone-forming patients. Follow-up ultrasonography 3 months later was normal. The results of our study suggest that ceftriaxone-treated patients may be at an increased risk of kidney stone formation. Stones passed spontaneously in all affected patients so the use of this effective drug can be safely continued. Close monitoring of ceftriaxone-treated patients with regard to kidney stone formation is recommended.     

Results of medical treatment and metabolic risk factors in children with urolithiasis

Data on conservative treatment in children with urolithiasis are limited. The aim of the study was to determine the metabolic etiology and results of conservative treatment in children with urolithiasis. We evaluated the clinical presentation and metabolic features of 112 children with urolithiasis. The mean age at diagnosis of urolithiasis was 3.9 (range 0.1–18) years, and follow-up duration was 16.7 (range 1–36) months. The most common presenting symptoms were flank or abdominal pain and restlessness (25%). Urine analysis revealed metabolic abnormalities in 92% of cases, including hypocitraturia (42%), hyperoxaluria (32.1%), hypercalcuria (25%), hyperuricosuria (9.8%), and cystinuria (2.7%). Patients who had metabolic risk factors were treated according to underlying metabolic abnormalities. About half of these patients were stone free or stones were diminished in size. These results showed that early recognition and treatment of urinary metabolic abnormalities will reduce the number of invasive procedures and renal damage in children with urolithiasis.     

Urolithiasis in Tunisian children: a study of 120 cases based on stone composition

The composition of urinary stones in children depends on socioeconomic conditions and hygiene, geographical area, and dietary habits. We analyzed urinary stones from 120 consecutive Tunisian children (81 males, 39 females) aged 5 months to 15 years. The stone was located in the upper urinary tract in 91 cases (76%). Stone analysis included both a morphological examination and an infrared analysis of the nucleus and the inner and peripheral layers. The main components of bladder calculi were whewellite (69%) and struvite (22%), whereas the main component of upper urinary tract calculi was whewellite (67%). The nucleus of bladder stones was composed of ammonium urate (45%), struvite (28%), cystine (10%), and carbapatite (7%). The nucleus of kidney and ureteral calculi was mainly composed of ammonium urate (38%), whewellite (24%), carbapatite (13%), or struvite (11%). Based on stone composition, urinary tract infection was involved in the nucleation or growth of a third of calculi. Endemic urolithiasis involving simultaneous nutritional, metabolic, and infectious factors, and defined by its nucleus composed of ammonium urate without struvite, represented 40% of cases. Exclusive metabolic factors – including genetic diseases such as primary hyperoxaluria, cystinuria, and hypercalciuria – were responsible for less than 25% of cases. Received: 6 March 1998 / Revised: 22 March 1999 / Accepted: 22 March 1999     

Practical use of investigations in patients with hematuria

OBJECTIVE: The majority of patients with microscopic hematuria undergo a complete evaluation resulting in negative findings. The outcome of patients with hematuria was analyzed in an effort to optimize the use of investigations. PATIENTS AND METHODS: The records for 404 patients who presented with hematuria were reviewed. Data were collected on demographics, type of hematuria, investigations, and final diagnosis. RESULTS: The hematuria was microscopic in 140 patients (35%) and gross in 264 patients (65%). In gross hematuria patients, 10% had urinary tract tumors and 12% had calculi. All patients with genitourinary tumors and 87% of patients with calculi had gross hematuria and/or > or =5 RBCs/HPF (red blood cells per high-power microscopic field) on urinalysis. The sensitivity and specificity were 94% and 6% for the dipstick urine test, 37% and 71% for urine cytology, 92% and 93% for computed tomography (CT), 50% and 95% for ultrasound scans, and 38% and 90% for intravenous pyelography, respectively. Logistic regression analysis showed that age and number of RBCs/HPF in the urinalyses were the only significant factors predicting genitourinary cancer. In patients < or =40 years old, there was one patient with malignancy and seven patients with stones. In older patients, there were 31 patients with malignancy and 32 patients with stones. CONCLUSIONS: Patients with <5 RBCs/HPF on three urinalyses are unlikely to have significant pathology and could possibly be followed up conservatively. Patients < or =40 years of age should have a noncontrast CT or ultrasound study if they present with microscopic hematuria, and a cystoscopy should be added if gross hematuria exists. In older patients, a pre- and postcontrast CT and a cystoscopy should be performed.