Calyceal Dilatation Research Articles

Creation of experimental urethral obstruction in utero: evaluation of fetal renal function.

Management of obstructive uropathy diagnosed in utero would be markedly enhanced by the availability of a simple, safe and quantitative fetal renal function test to predict postnatal renal function. In order to allow experimental evaluation of such a parameter, we adjusted a model of complete urethral obstruction with urachal ligation in 30 fetal lambs at 79 or 99 days of gestation. The method described allows obstruction in male and female fetuses as early as 79 days of gestation, with an overall high survival rate (control: 12/14; obstructed: 23/29), although lower (6/12) when obstruction is performed early (79 days) during gestation. Consequences of obstruction were examined on the 121st day of gestation. Severe hydronephrosis, ureteral and calyceal dilatation, with or without ascites and pulmonary hypoplasia were observed in all fetuses; creatinine clearance determined in utero was decreased in both groups with obstruction (early and late) vs control group: 1.15 +/- 0.5, NS, and 0.58 +/- 0.4, p < 0.01 vs 1.61 +/- 0.8 ml/min/kg respectively. In both obstructed groups, fetuses with ascites displayed lower plasma creatinine concentration and higher creatinine clearance values when compared to fetuses without ascites. In conclusion, the experimental model of obstructive uropathy described appears efficient and easily reproducible, allowing therefore the evaluation of a predictive parameter of postnatal renal function. Our preliminary results suggest that renal fetal function is more dependent on the degree of obstruction than on the term of its creation.

Ultrasonic evaluation of hydronephrosis during pregnancy and puerperium.

Hydronephrosis frequently occurs during pregnancy. The etiology and significance of this phenomenon are not clearly understood. Further, little information regarding changes in the kidneys during pregnancy and early postpartum is available. This study uses real-time ultrasound in order to investigate whether or not there is a relationship between the degree of calyceal dilatation, kidney size, and creatinine clearance value. Two hundred and eighty-six patients, including 175 pregnant and 111 puerperal individuals, were examined. The overall incidence of hydronephrosis was 67% in the pregnant and 39% in the puerperal women. Moderately and severely affected kidneys were significantly larger than the mildly affected and nonaffected kidneys (p < 0.05, p < 0.001). The creatinine clearance value was lower in patients with severe hydronephrosis than in those with mild and moderate hydronephrosis and in the nonaffected patients, albeit with no statistical significance.

Renal insufficiency secondary to 2,8-dihydroxyadenine urolithiasis

A 48-year-old man with a history of recurrent urolithiasis and chronic renal failure underwent a nephrectomy for a renal mass. At surgery the mass proved to be a calculus impacted in a dilated calyx. Gross examination of the kidney revealed chalky white deposits in the deep medulla and papillary tips. Histologic examination revealed chronic interstitial nephritis with brown spicules within some tubular epithelial cells and larger deposits of brown crystals within tubular lumina, the interstitium of the medulla, and papillary tips. Polarization microscopy revealed individual crystals scattered throughout the renal parenchyma. Although the arrangement of the crystals was reminiscent of uric acid, and, in fact, a clinical diagnosis of gouty nephropathy was made, x-ray diffraction analysis demonstrated crystals of 2,8-dihydroxyadenine. Enzymatic studies confirmed the complete absence of adenine phosphoribosyltransferase activity in erythrocyte lysates.

Segmental replacement of the left ureter using a pedicted and tapered gastric flap in dogs

Segmental replacement of the left ureter was done using a pedicted and tapered gastric flap in ten dogs. All were followed up for 12 weeks. The results of the operation were good. Serum electrolyte imbalance was not observed in any dog. Intravenous pyelograms were normal except in one animal that had mild calyceal dilatation. Postoperative values of blood urea nitrogen (BUN) and creatinine were normal when compared with preoperative values. Pathologic examinations of the left kidney, left ureter, and gastric ureter of the dogs were normal. We believe that incorporating a pedicled and tapered gastric flap into the urinary tract to bridge a ureteral defect is a new, safe, and effective clinical alternative.

Calcified hydronephrosis in pregnancy

A 31-year-old woman, who had suffered from urinary calculi for 9 years, presented with left-sided renal colic when 36 weeks pregnant in her third pregnancy. Renal function had always been normal and renal ultrasonography on presentation showed dilated calyces with echogenic margins in both kidneys (Figs 1a&amp;b). Several areas of focal echogenicity with associated acoustic shadowing suggested calculi within the calyces, and the left upper ureter was dilated. Treatment was conserva- tive and following successful delivery an abdominal film showed bilateral nephrocalcinosis together with multiple calculi in the left kidney and a large calculus in the line of the left ureter (Fig. 2).

Microscopic hematuria and calculus-related ureteral obstruction

The evaluation of patients with ureteral calculi in the emergency department has historically included urinalysis (UA) and intravenous pyelograms (IVP). This retrospective study was done to determine if a statistically significant relationship existed between the degree of calculus-related ureteral obstruction, proven by IVP, and the presence or absence of microscopic hematuria. Urine red blood cells were recorded as less than 3 rbc/hpf (negative) or greater than or equal to 3 rbc/hpf (positive). IVPs were recorded as nonsevere or severe. IVP criteria were based on the presence or absence of extravasation, greater than 2-hour ureteral filling times, and a numerical scoring system of 1 to 4 for ureteral or calyceal dilatation and nephrogenic effect. Eighty-nine men (72%) had non-severe obstructions and 34 (28%) had severe obstructions. Twenty-five women (68%) had nonsevere obstructions and 12 (32%) had severe obstructions. Of the 28 patients with normal UAs, 11 had severe ureteral obstructions and 17 had nonsevere ureteral obstructions. There were no statistically significant differences between the presence or absence of significant microscopic hematuria and the presence or absence of severe ureteral obstruction. Microscopic hematuria is neither sensitive nor specific in determining the degree of calculus-related ureteral obstruction.

Ultrastructural Aspects of the Human Peripheral Vestibular System

The sensory epithelia from the membranous labyrinths of 4 patients were examined by transmission electron microscopy. The distribution ratio of type 1 to type 2 cells was recorded, compared for each sensory area and correlated with age. An ultrastructural assessment confirmed generalized patterns consistent with autolytic and preparation artefact, viz. calyceal dilatation, cytoplasmic protrusions and some sensory hair loss. More specific features, i.e. lipofuscin accumulation, membrane-bound inclusions and neural degeneration were consistent with pre-mortem pathological change. In 2 patients, total nerve fibre counts of 15,766 and 19,741 were obtained. Total fibre counts correlated with the sensory cell density of the innervated areas. Differential counts of the superior and inferior vestibular nerves suggested that there was a reduced number of fibres in the superior division of both patients, in comparison with established normative data. Morphometric analysis of the constituent fibre diameters revealed a skewed distribution with a modal value of 6 microns for both patients.

Ectopic ureterocele without ureteral and calyceal dilatation (ureterocele disproportion): findings on urography and sonography

Eight infants and children (six girls) were seen over a 13-year period with duplex collecting systems and ectopic ureteroceles. In each, there was striking dissimilarity in size between the large ureterocele and its diminutive ureter and calyces. The upper moiety did not function and, except for the ureterocele, the indirect urographic and direct sonographic signs of duplication were absent or subtle. We call this entity ureterocele disproportion. Seven patients presented with urinary infection and one was found to have hydronephrosis of a dilated lower moiety in utero. Five had ipsilateral lower-pole reflux, which ranged in degree from 3 to 5 (on a scale of 1-5). Two had bilateral duplication; one of these had a typical contralateral ectopic ureterocele. The diagnosis of ureterocele disproportion was strongly suggested by urography and sonography and was confirmed at cystoscopy by direct puncture of the ureterocele and opacification of the upper moiety. All had surgery. The approach varied and depended on the status of the lower moiety and the contralateral kidney. One had incision of the ureterocele only. Five with lower-pole reflux had excision of the ureterocele and ipsilateral common-sheath reimplantation.

The impact of computed tomography in the diagnosis and postoperative follow-up of ureteric obstruction in aorto-iliac aneurysmal disease

Between 1979, the advent of computed tomography in our institution, and 1987 we have treated 520 aorto iliac aneurysms surgically, almost 2/3 on an elective basis, the others (183 = 35.2%) being ruptured. Among non-ruptured aneurysms 220 were symptomatic and 19 of 20 cases with ureteric entrapment occurred in these patients corresponding to 8.6% of this subgroup and verified at surgery. In all of these cases the association between ureteric obstruction and the underlying aneurysmal disease was clearly documented by computed tomography. In 8 patients ureteric entrapment was caused by an inflammatory aneurysm, in 12 cases by an arteriosclerotic aneurysm which in one case was a largely expanded internal iliac aneurysm left behind during previous surgery for a ruptured aorta aneurysm. Postoperative follow-up studies of the 8 patients with an inflammatory aneurysm revealed a time-dependent regression heading towards complete disappearance of perivascular fibrosis. Because of potential difficulties associated with the surgical treatment of inflammatory aneurysms it is important to identify perivascular fibrosis and its extent and localization pre-operatively, which can only be achieved by a CT scan. Simultaneously, CT offers information concerning the presence and degree of pyelectasis and calyceal dilatation, identifies the localisation of ureteric entrapment, defines the extent of aneurysmal disease of the iliac arteries, is best-suited for postoperative follow-up in all of the cases and has the most to offer if contrast medium investigations are contra-indicated in the presence of renal insufficiency. Probably the main reason, if not the only one for preoperative angiography, is to demonstrate associated anomalies of the visceral arteries the state of which however, can be just as well assessed by duplex sonography. Thus, computed tomography is the single most important diagnostic tool in the assessment of aorto-iliac aneurysmal disease especially when associated with ureteric entrapment.

Renal Ultrasound Evaluation of Urinary Tract Infections in Children

Ultrasonography of the kidney may replace the intravenous pyelogram as the study of choice in identifying treatable abnormalities in children with urinary tract infection. In a series of 64 consecutive children with urinary tract infection in whom an intravenous pyelogram, renal ultrasound, and voiding cystogram were performed, only one treatable abnormality (calyceal dilation) was identified by intravenous pyelogram, and it was not detected by ultrasound. Eleven children showed vesicoureteral reflux on the cystogram. In an additional 43 children in whom intravenous pyelogram was done only if the ultrasound or cystogram were abnormal, there were five abnormal cystograms. Four treatable abnormalities were identified by ultrasound, and there were confirmed by the intravenous pyelogram. Ultrasound should replace the intravenous pyelogram in children with a normal cystogram because of its accuracy, safety, and high patient acceptance. We have also documented a significant volume increase with acute infection in one or both kidney(s) of those children having upper urinary tract infection. Fifteen of 18 children with upper urinary tract infection had volume increases of 30% or more in at least one kidney; whereas only four of 21 children with lower urinary tract infection had increases of greater than 30% (P less than .005). Ultrasound volume measurements provide a new, noninvasive method for identifying the probable site of urinary tract infection.

Hydronephrosis in Pregnancy

Two cases of significant hydronephrosis of pregnancy and their management are detailed. Measurements of calyceal diameters in control and pregnant patients of varying gestational ages are presented. Calyceal dilatation in pre-and postvoid states for all patients examined is compared, with no differences noted. Although there was a general trend toward increasing calyceal diameters throughout pregnancy, high intragroup variation was present in each group. There were no significant differences detected between gestational age groups and between right and left kidneys. Ultrasonography can be used as the initial method of evaluation in symptomatic pregnant patients. The absence of hydronephrosis virtually eliminates obstructive disease, while significant hydronephrosis may be present without disease. The hydronephrosis of pregnancy is highly variable and exhibits wide ranges of physiologic change. Medical management should be based on symptomatology rather than "hydronephrosis" as a pathologic diagnosis.

Urodynamic consequences of a direct pyelocystostomy at autotransplantation of the kidney.

The urodynamic consequences of renal autotransplantation and pyelocystostomy were studied in 17 male and 3 female patients. The indications of the procedure were urothelial tumor of the upper urinary tract, remaining outflow obstruction after conventional pyeloplasty and recurrent stones. The mean observation time was 31 months (range 3-50 months). The micturition flow rate was unchanged. There was an insignificant increase in residual urine. No evidence of any clinically significant disturbance of the sensory or motor bladder innervation or reduction of the functional bladder capacity was found. Urethrocystography showed transient dilatation of calyces at micturition. Urinary tract infections, when present, had the same pattern as preoperatively. Thus, autotransplantation of the kidney with a wide, direct pyelocystostomy is consistent with essentially normal urodynamics of the transplanted renal pelvis and the bladder.

Pregnancy hydronephrosis--a longitudinal ultrasonic evaluation.

The progression of physiological hydronephrosis through the 3 trimesters of pregnancy was assessed by ultrasonic measurement of calyceal diameters in 56 asymptomatic patients in a longitudinal study. A grading system basing on the maximum calyceal diameter was used; 89% of the patients showed at least mild dilatation before delivery. There was a preponderance of the right side being affected. In 6 patients (10.7%), severe dilatation was demonstrable and in all of them its onset appeared to be in the second trimester. The likelihood of progression to moderate or severe dilatation when only mild dilatation is demonstrated in the second trimester is low. Furthermore, it is not common for moderate dilatation in the second trimester to progress to severe dilatation in the third trimester. These findings appear to support the mechanical theory in the genesis of pregnancy hydronephrosis. Rapid regression of calyceal dilatation is not apparent in the first 5 days after delivery.

Radionuclide studies of chronic schistosomal uropathy.

Fifty patients with chronic urinary tract schistosomiasis were studied with 99mTc-DTPA. All had a flow study, sequential analog imaging, and digital imaging for 25-35 minutes (20-sec. frames). Time-activity curves (DTPA renograms) were extracted; 12 patients had 131I-Hippuran probe renograms as well. Renal changes included diminished perfusion and structural abnormalities ranging from minor calyceal dilatation to overt hydronephrosis. Ureteral changes included dilatation, tortuosity, and kinking. Marked distortion of the ureterovesical junction was seen in some patients due to periureteral and perivesicular fibrosis, which is a major factor in upper urinary tract damage. Renograms showed varying obstruction and parenchymal damage. Nuclear medicine complements excretory urography and is sometimes preferable for visualization of the ureters. After the initial urogram, sequential DTPA scanning and renography are sufficient for follow-up.

Development of the bovine metanephros.

This study presents the gross and light microscopic features of the developing bovine metanephros. Thirty-six specimens, consisting of 19 whole embryos and foetuses, 15 foetal metanephroi, one calf kidney and one cow kidney, were examined. The development of the collecting duct system and nephron induction and formation were similar to those processes described for the human kidney but appeared to follow an accelerated time course. The bovine metanephros by 15–18 weeks gestation, had a well organized internal structure consisting of dilated major calyces, prominent minor calyces and papillae, and a definize cortex and medulla. Nephron induction started as early as 4–6 weeks gestation and was completed around 28 weeks.

Segmental “hypoplasia” of the kidney (Ask-Upmark)

Severe segmental renal atrophy with loss of parenchymal elements in small kidneys is commonly known as segmental hypoplasia. The scars are seen as cortical depressions overlying shrunken medullary pyramids and their dilated calyces, and are characterized histologically by colloid-filled tubular microcysts and a paucity or absence of glomeruli. This lesion has been identified in 17 patients, 11 female and 6 male, between 6 and 23 years of age. Eleven patients had hypertension, which developed in six while they were under observation. Thirteen had histories of urinary tract infection, and 16 had evidence of vesicoureteric reflux. Seven patients had impaired renal function (GFR less than 40 ml/minute/1.73 m2). Abnormal metanephric differentiation (dysplasia) in two specimens, one in association with posterior urethral valves, suggested an occasional intrauterine origin of the abnormality. Twelve patients had radiographic evidence of decreasing renal size over two to five years of observation, even after surgical correction of reflux, in four of them unaccompanied by infection. We conclude that segmental "hypoplasia" is an acquired lesion, although it sometimes has intrauterine origins, and that it is commonly associated with vesicoureteric reflux, even in the absence of demonstrable infection.

Sonographic evaluation of the nonfunctioning kidney.

The results of B-mode ultrasound examinations in 113 consecutive patients with unilateral renal nonfunction or severe azotemia were reviewed. The causes of nonfunction included the following: hydronephrosis; renal parenchymal disease; renal agenesis; atrophy or dysplasia; multicystic, medullary cystic, and polycystic kidneys; renal arterial or venous occlusive disease; extensively infiltrating neoplasm. The sonographic findings were consistent with the final diagnosis in 92 percent of the cases. A coronal view of the kidney for diagnosing hydronephrosis is described. This view demonstrates the dilated calyces in continuity with the renal pelvis and, when combined with transverse views, improves the reliability of the sonographic diagnosis of hydronephrosis. In cases where the renal landmarks appear totally normal, obstruction can be excluded as a cause of nonfunction, and retrograde pyelography may be avoided. The sonographic manifestations of other parenchymal abnormalities associated with nonfunction, such as cystic renal disease, glomerulonephritis, and renal transplant rejection, are also discussed.

Editorial Board

Urinary tract (UT) dilation is sonographically identified in 1–2% of fetuses and reflects a spectrum of possible uropathies. There is significant variability in the clinical management of individuals with prenatal UT dilation that stems from a paucity of evidence-based information correlating the severity of prenatal UT dilation to postnatal urological pathologies. The lack of correlation between prenatal and postnatal US findings and final urologic diagnosis has been problematic, in large measure because of a lack of consensus and uniformity in defining and classifying UT dilation. Consequently, there is a need for a unified classification system with an accepted standard terminology for the diagnosis and management of prenatal and postnatal UT dilation.A consensus meeting was convened on March 14–15, 2014, in Linthicum, Maryland, USA to propose: 1) a unified description of UT dilation that could be applied both prenatally and postnatally; and 2) a standardized scheme for the perinatal evaluation of these patients based on sonographic criteria (i.e. the classification system). The participating societies included American College of Radiology, the American Institute of Ultrasound in Medicine, the American Society of Pediatric Nephrology, the Society for Fetal Urology, the Society for Maternal-Fetal Medicine, the Society for Pediatric Urology, the Society for Pediatric Radiology and the Society of Radiologists in Ultrasounds.The recommendations proposed in this consensus statement are based on a detailed analysis of the current literature and expert opinion representing common clinical practice. The proposed UTD Classification System (and hence the severity of the UT dilation) is based on six categories in US findings: 1) anterior-posterior renal pelvic diameter (APRPD); 2) calyceal dilation; 3) renal parenchymal thickness; 4) renal parenchymal appearance; 5) bladder abnormalities; and 6) ureteral abnormalities. The classification system is stratified based on gestational age and whether the UT dilation is detected prenatally or postnatally. The panel also proposed a follow-up scheme based on the UTD classification.The proposed grading classification system will require extensive evaluation to assess its utility in predicting clinical outcomes. Currently, the grading system is correlated with the risk of postnatal uropathies. Future research will help to further refine the classification system to one that correlates with other clinical outcomes such as the need for surgical intervention or renal function.

Transitional cell carcinoma of the kidney

Transitional cell carcinoma is an uncommon disease of the renal pelvis, the diagnosis of which depends largely upon radiological investigation. Thirty-eight such tumours in 37 patients have been reviewed to establish the examination of choice. High-dose excretion urography, tailored to the presenting problems, is the primary investigation and the results fall into five main groups. Each presents different differential diagnostic problems. Discrete filling defects within the pyelogram (group I) may be overlooked, but, when seen, can be diagnosed on urography alone. Filling defects with dilated calyces (group II) are easily seen and readily diagnosed. Calyceal obliteration (group III) presents more difficulty in diagnosis and may require retrograde pyelography and selective renal angiography. Hydronephrosis with renal enlargement (group IV) is easily confused with uncomplicated primary pelvic hydronephrosis and will usually require antegrade pyelography for diagnosis. Reduced function without renal enlargement (group V) cannot be diagnosed on excretion urography and requires both retrograde pyeloureterography and selective renal angiography.

The layered pyelogram in hydronephrosis.

Fifty patients were studied with erect films at excretory urography. Twenty-eight had hydronephrosis, bilateral in two cases; a total of 30 hydronephrotic kidneys were therefore investigated. Thin layers of contrast medium were shown in the dilated calyces in 29 of the 30 kidneys. The layered pyelogram is a simple, sensitive urographic sign of hydronephrosis, which may be demonstrated in the absence of a discernible pyelogram in the routine film or tomograph. The basis of layering has been investigated by simple experiments. Since the layered pyelogram may be the only urographic evidence of a poorly excreting hydronephrotic kidney, erect films should be routinely used at excretory urography when this condition is to be diagnosed or excluded.