Diagnosis Of Obstructive Uropathy Research Articles

Kidney Efficiency Index - quantitative parameter of a dynamic renal scintigraphy. I. Theory and preliminary verification.

One of the basic clinical indications for dynamic renal scintigraphy (DRS) is a diagnosis of obstructive uropathy and/or nephropathy. Currently, a basic quantitative criterion for diagnosing nephropathy is the percentage of individual kidney's contribution in the global uptake of a radiopharmaceutical from the blood (so-called Split Function - SF). From a clinical point of view, a parameter evaluating a radiopharmaceutical uptake and reflecting the efficiency of a specific kidney, determined independently of the total uptake of both kidneys, would be much more useful. Based on a Rutland theory, a kidney uptake constant K proportional to a radiotracer uptake by individual kidney was introduced and applied to DRS with 99mTc-ethylene-1-dicysteine (99mTc-EC). In addition, a kidney efficiency index (KEi) was also worked out as a new parameter obtained by dividing the uptake constant K by the surface of the ROI of a given kidney, which can be interpreted as the average "efficiency" of clearance of a kidney. K and KEi values were verified in 72 studies selected retrospectively from patients referred routinely for DRS, with available current level of blood creatinine, used for calculation of estimated GFR (eGFR) according to a CKD-EPI formula. After splitting of eGFR values into individual kidneys according to SF, single kidney eGFR values (SKeGFR) were obtained and then used as a verification method for SF, K and KEi values. Correlation between SF and SKeGFR values, rsp = 0.64, was significantly weaker (p < 0.0022) than the correlation of SKeGFR values with K uptake constants and KEi indices: 0.90 and 0.84, respectively. Uptake constant K and KEi, as quantitative parameters, give the opportunity to analyze a function of each kidney separately and in an absolute way. KEi also allows for a reliable assessment of kidneys of atypical sizes (larger or smaller than average). It also gives the opportunity to create normative values for this parameter and may be useful in a number of clinical situations where the diagnostic effectiveness of such a relative parameter as SF, is severely limited, e.g. in assessing a large kidney with hydronephrosis or while differing a cirrhotic from hypoplastic (i.e. a small but properly functioning) kidney.

Role of doppler sonographic evaluation of intra-renal hemodynamic changes in diagnosis of obstructive uropathy and in differentiation of acute and chronic obstructive uropathy

Role of doppler sonographic evaluation of intra-renal hemodynamic changes in diagnosis of obstructive uropathy and in differentiation of acute and chronic obstructive uropathy

Magnetic resonance urography in the evaluation of obstructive uropathy

Purpose: The purpose of this study was to study the utility of magnetic resonance urography (MRU) in the evaluation of obstructive urological diseases in comparison to intravenous urography (IVU). Materials and Methods: The study was carried out over a period of 2 years. A total of 55 patients were included in this study with ages between 14 and 70 years (average age 37 years). The patients were selected on the basis of ultrasonographic findings of hydronephrosis. The patients were subjected to IVU followed by static and dynamic MRU. The results obtained were compared and the inferences drawn thereof. Results and Conclusions: MRU has high sensitivity in the diagnosis of urinary tract obstruction, detecting the level of obstruction and acts as an aid in the diagnosis of obstructive uropathy, thus showing promising results. MRU is safer than IVU due to avoidance of iodinated contrast material and could also be done without using contrast material so having less contrast related events.

The profile of patients with obstructive uropathy in Cameroon: case of the Douala General Hospital

IntroductionObstructive uropathy can lead to irreversible kidney damage. The etiology largely determined by the patient's age can be benign or malignant. This study aimed at determining the profile and outcome of patients with obstructive uropathy in Cameroon.MethodsA cross sectional study carried out in the urology unit of the Douala General Hospital, including patients with a diagnosis of obstructive uropathy seen from January 2004 to December 2013. Clinical profile, treatment and outcome data were obtained from patients records.ResultsOf the 229 patients included 69% were men, mean age 50 ±18 years. Associated comorbidities were hypertension, diabetes, and HIV. Mean haemoglobin 8,40±2,4g/dl, mean GFR 10,3 ±10ml/min, 94 (41%) patients needed emergency dialysis. Symptoms at presentation: asthenia (57%), anorexia (55%), loin pain (37%), vomiting (28%), oedema (20%), and anuria (15%). Urinary tract infection was present in 33 patients. Main aetiologies of obstruction: urolithiasis (35%), begnin prostatic hypertrophy (27%), prostatic cancer (12%), cervical cancer (16%), and congenital malformations (5%). Drainage was effective in 102 (45%) patients, 63 (28%) recovered completely, 91 (41%) were loss to follow up, 49 (22%) died and more women (p = 0.02). Mortality was associated with prostatic cancer (p = 0.000), cervical cancer (p = 0.004) and radiotherapy (p = 0.03).ConclusionPatients with obstructive uropathy presented with significant impaired renal function. Main causes were urinary stones, prostatic hypertrophy, prostatic and cervical cancers. Renal recovery was poor, loss to follow up and mortality high. Specific strategies to target improvement in renal recovery and patient's survival are needed in this patient's group.

Urinary Infections in Children

Urinary tract infection (UTI) is a common infection in infants and children. During infancy, boys are more commonly affected than girls and thereafter, female preponderance is found. Presentation varies among different age groups. Clinical features in neonates and young infants are non-specific, manifest as septicemia where a high index of suspicion is needed. Older children typically present as simple or complicated UTI. Rapid diagnosis, institution of early treatment and further evaluation by imaging modalities are of utmost importance. The prevention of recurrent UTI and detection of congenital anomalies of kidney and urinary tract are major objectives in the management. Use of ultrasound is required to detect underlying congenital abnormalities, whereas voiding cystourethrogram and dimercaptosuccinic acid (DMSA) scan are useful in the diagnosis of obstructive uropathy and vesicoureteric reflux and renal scar, respectively. The children requiring surgical interventions are to be recognised early to prevent recurrent UTI. The treatment of vesicoureteric reflux by chemoprophylaxis in lower grades and surgical treatment in higher grades are important consideration in prevention of recurrent UTI. This is required to prevent renal parenchymal damage and scarring that can cause hypertension and progressive renal insufficiency in later life.

Evaluation of Differential Renal Function and Renographic Patterns in Patients with Dietl Crisis

We analyzed preoperative and postoperative differential renal function and characterized the renographic findings in patients with ureteropelvic junction obstruction associated with Dietl crisis. Patients with Dietl crisis who underwent pyeloplasty between January 2004 and December 2010 were classified by renographic presentation. Patients in group 1 were diagnosed with cortical retention, those in group 2 had an initial obstructed scan (T1/2 of 20 minutes or more and no cortical retention) and those in group 3 had an initial nondiagnostic scan (T1/2 of less than 20 minutes and no cortical retention). Renographic parameters were used to analyze each group. A total of 59 patients met criteria for study inclusion. The 13 patients in group 1 demonstrated the most significant recovery of function after pyeloplasty (mean differential renal function change 13.59%). The 38 patients in group 2 exhibited a mean differential renal function change of 43.06% (range 20% to 54.6%) and mean preoperative T1/2 of 64.31 minutes. Pyeloplasty was performed in all 8 patients in group 3 based on subsequent diagnostic scan (4 patients) or increased hydronephrosis on other imaging associated with further symptomatic episodes (4). Initial renographic patterns noted in group 3 included biphasic curves, diminished clearance after 15 minutes upright or symptoms despite nonobstructive drainage. Interpretation of diuretic renography requires the assimilation of multiple parameters since patients with Dietl crisis can exhibit variability in renographic patterns due to the intermittent nature of ureteropelvic junction obstruction. Cortical retention represents a specific and pathognomic finding of acute ureteropelvic junction obstruction. With appropriate evaluation of these parameters, obstruction can be reliably diagnosed and appropriate surgical candidates chosen.

Application of renal doppler sonography in the diagnosis of obstructive uropathy in patients with spinal cord injury

Tseng F-F, Bih L-I, Tsai S-J, Huang Y-H, Wu Y-T, Chen Y-Z. Application of renal Doppler sonography in the diagnosis of obstructive uropathy in patients with spinal cord injury. Arch Phys Med Rehabil 2004;85:1509–12. Objectives To assess renal resistive index (RI) changes in patients with spinal cord injury (SCI) who have obstructive uropathy and to determine if an RI of 0.7 or more is useful in identifying such patients. Design Prospective cross-sectional study. Setting Rehabilitation hospital affiliated with a medical university. Participants A convenience sample of 99 kidneys of 51 SCI patients (38 men, 13 women; mean age, 38.8±14.0y) with neuropathic bladder dysfunction. Interventions Ultrasonic examination to assess the degree of hydronephrosis, Doppler sonography to calculate renal vascular RIs, and radioisotopic renography to assess renal function and to determine excretory curves. Kidneys were assigned to control or obstructive uropathy groups, and RIs were compared for statistical significance (Student t test) and to assess whether an RI of 0.7 is a distinguishing criterion. Main Outcome Measures RI and sensitivity. Results Average RIs were .58±.07 in the control group (71 kidneys) and .65±.08 in the uropathy group (28 kidneys) ( P<.001). The sensitivity of using an RI of 0.7 or more to identify patients with obstructive uropathy was 39%. The c statistic of the receiver operating characteristic curve was .72. Conclusions RIs increased in SCI patients with obstructive uropathy. In patients with SCI, urinary findings fit the chronic partial obstruction pattern. A renal RI of 0.7 or more was a poor indicator of obstructive uropathy in such patients.

Diuretic renogram clearance half-times in the diagnosis of obstructive uropathy: effect of age and previous surgery

Diuretic renography with radiotracers has been used successfully to diagnose obstruction in patients with hydronephrosis. Controversy persists with regard to the best approach for the interpretation of renogram curves: visual analysis or a quantitative index, i.e. the clearance half-time. The latter is often reported to be in the intermediate or non-diagnostic range. It is important to measure the incidence of equivocal half-times in various subsets of patients with hydronephrosis in order to determine in which settings the measurement of this index may be clinically useful. We performed a retrospective study of diuretic renograms performed at our institution between 1997 and 2000 for the evaluation of suspected uretero-pelvic junction (UPJ) obstruction. Vigorous intravenous hydration, exceeding current guidelines, was employed in these patients. Three hundred and seventy-seven renogram curves in 205 patients were analysed. Patients were divided into three groups: >1 year of age; <or=1 year of age; and those who had previously undergone surgical correction of obstruction regardless of age. Patients with reflux or anatomical abnormalities of the urinary tract, those with chronic renal failure, those with bilateral normal clearances before furosemide administration and those with unilateral normal clearances before furosemide administration with contralateral poor renal function were excluded. In the remaining 119 patients, 205 clearance half-times were classified as normal before furosemide, normal after furosemide (half-time, <10 min), prolonged (half-time, >20 min) or intermediate (half-time, 10-20 min). In patients >1 year of age, 37% of 101 renograms showed normal half-times before furosemide, 20% showed normal half-times after furosemide, 44% showed prolonged half-times and none (0%) showed an intermediate half-time. In patients </=1 year of age, there was a statistically significantly different distribution, with 48% of 64 renograms showing normal washout before furosemide, 16% showing normal clearance after furosemide, 19% showing abnormal half-times and 17% showing intermediate half-times. In 33 renograms from patients who had undergone corrective surgery, 49% had normal half-times, 24% had prolonged half-times and 27% had intermediate half-times. It can be concluded that, when using the selection criteria, hydration, acquisition and processing protocols and half-time definition employed in this study, the addition of a clearance measurement in patients older than 1 year with suspected UPJ disease enhances patient classification and may improve the diagnostic confidence. There was a significantly higher incidence of intermediate half-times in patients with native disease aged <1 year than in those >1 year. Caution is advised when interpreting this finding in this age group. The measurement of washout was less useful in patients who had undergone a corrective procedure, because of the high rate of 'indeterminate' and 'abnormal' values in spite of successful surgery. Vigorous intravenous hydration, exceeding current standards, may have contributed to the lower incidence of intermediate half-times than reported previously.

Resistive indices in the evaluation of infants with obstructive and nonobstructive pyelocaliectasis.

Diagnosing obstructive uropathy by renal resistive indices calculated from duplex Doppler sonographic waveforms has been supported as well as challenged in the radiology literature relating to adults. Despite reports of normally higher resistive indices in children as compared to adults, two studies have documented high sensitivity and specificity of renal Doppler sonography in the diagnosis of obstructive uropathy in children, using the same discriminatory criterion of a resistive index of 0.7 or greater as used in adults. We evaluated 43 infants with significant or bilateral pyelocaliectasis secondary to both obstructive and unobstructive uropathy and found no significant difference in the mean resistive indices or the mean difference in resistive indices of two kidneys in one patient. We conclude that Doppler sonography in infants has no value in differentiating obstructive from nonobstructive pyelocaliectasis.

Detection of obstructive uropathy in the fetus: predictive value of sonographic measurements of renal pelvic diameter at various gestational ages.

The goal of our study was to analyze the fetal renal pelvic diameters measured sonographically at several gestational intervals in live-born neonates subsequently found to have either obstructive uropathy or normal kidneys. This information will improve the efficacy of sonography in the diagnosis of obstructive uropathy. From an ongoing prospective study assessing the significance of fetal renal pelvic diameters of 4 mm or more at obstetric sonography, the findings in 29 obstructed kidneys in 24 babies were compared with the findings in 380 kidneys from 233 infants who had no obstruction. Twenty-three infants had unilateral obstruction of the ureteropelvic junction, two had unilateral renal obstruction at the ureterovesical junction, one had posterior urethral valves and in addition had both kidneys obstructed because of obstruction at the ureterovesical junction, one kidney was obstructed because of megaloureter, and one kidney was obstructed because of obstruction in a duplex collecting system. Obstruction was identified on nephrostograms, excretory urograms, or radionuclide renograms. The sonographic findings were compared at three gestational age ranges: 16-23 weeks' gestation, 24-30 weeks' gestation, and 31-40 weeks' gestation. The progression of pelvic dilatation in both groups (12 obstructed and 86 unobstructed) was analyzed for the subset of kidneys examined in all three time periods. At 16-23 weeks' gestation, the difference in mean pelvic diameter between obstructed and unobstructed kidneys was not statistically significant, but the difference between obstructed and unobstructed groups at 24-30 weeks' and 31-40 weeks' gestation was significant (p < .001). Renal pelvic diameter showed a much greater rise in diameter through pregnancy in the obstructed group than in the unobstructed group (p < .0003). The sensitivity of the cutoff point of 4-mm renal pelvic diameter for detecting obstruction was 76% before 23 weeks' gestation, including kidneys with a marked decrease in function postnatally; the sensitivity of a 10-mm cutoff point at 16-23 weeks' gestation was 12%. The likelihood that a fetus had renal obstruction increased with increasing diameter of the fetal renal pelvis in all three time periods. Kidneys with significant obstruction postnatally may have no dilatation of the renal pelvis before 23 weeks' gestation. Most obstructed kidneys had pelvic diameters of less than 10 mm before 23 weeks' gestation. During pregnancy, renal pelvic diameter increases at a greater rate in kidneys that later are shown to be obstructed than in those that are not obstructed.

Antenatal diagnosis of renal anomalies with ultrasound: I. Obstructive uropathy

During a 5-year period, a diagnosis of obstructive uropathy was made in 25 fetuses. Eight of them had unilateral obstruction and 17 were affected bilaterally. The most common condition encountered was urethral obstruction by posterior valves. The site and nature of the obstruction were correctly identified in 22 of the 25 fetuses. Among the 17 who had bilateral obstruction, only three survived. In contrast, only one infant with unilateral obstruction died (of unrelated causes). Oligohydramnios in low-level (urethral) obstruction was a uniformly lethal finding. Relief of urethral obstruction in two fetuses after 20 weeks of gestation did not result in survival of the infant, whereas shunting prior to 20 weeks in one fetus seemed to have a beneficial effect. On the basis of this experience, we suggest that unilateral obstruction would be treated best by conservative management, while in bilateral obstruction invasive treatment may be effective if initiated early in gestation, before significant oligohydramnios occurs.

Ultrasonography in the diagnosis of obstructive uropathy caused by papillary necrosis

Ultrasonography in the diagnosis of obstructive uropathy caused by papillary necrosis

Obstructive Uropathy

In recent years there has been a renewed interest in the disease pyelonephritis. The role of the indwelling catheter, the cystoscope, and retrograde pyelography in the production of bacteriuria and pyelonephritis has been well emphasized. As a consequence, the fear of initiating active renal infection has led to new methods of obtaining and interpreting voided urine specimens in order to avoid catheterization for diagnostic purposes. However, along with this fear has developed a tendency to limit the use of tools which for many years have aided the physician in making the diagnosis of obstructive uropathy, a disease often equally as serious in consequence to the patient as pyelonephritis itself. The following three cases, seen recently in consultation by the urology service, emphasize the importance of considering obstruction in all cases of urinary infection and azotemia and using the diagnostic tools available when indicated as early as possible. Report of Cases