Orthostatic Proteinuria with Nutcracker Phenomenon: Case Report

Orthostatic proteinuria has been recognized as a benign condition with a good prognosis and has not been associated with any underlying glomerular disease. The pathogenesis of orthostatic proteinuria is unclear. Recently, a few foreign reports suggested that the nutcracker phenomenon, which is known as a cause of asymptomatic hematuria, may also be a major cause of orthostatic proteinuria. We report a case of a 12-year-old female patient presenting only with orthostatic proteinuria, who was diagnosed as having nutcracker phenomenon by Doppler study and venography.

CT Findings of Acute Pyelonephritis in Children:Correlation with Clinical Manifestations

PURPOSE: The purpose of this study was to evaluate the CT findings of acute pyelonephritis (APN) in children and to assess the correlation between these findings, clinical parameters and renal scar development, as seen on follow-up CT scans. MATERIALS AND METHODS: Contrast-enhanced CT scans of thirty children in whom APN had been diagnosed were assigned to one of three groups according to whether an abscess had formed, and then to subgroups on the basis of the number of lesions in the renal parenchyme. Initial CT findings were retrospectively correlated with five clinical parameters (maximal body temperature, fever duration, leukocytosis, pyuria and admission period) and renal scar development, as seen on follow-up CT (n=12). RESULTS: CT scans demonstrated linear, wedge-shaped, low-density renal parenchymal lesions in 35 kidneys of 25 patients and abscesses in seven kidneys of seven patients, but no abnormal lesions in five patients. In the three groups there was correlation between these findings and some clinical parameters (maximal body temperature, fever duration and admission period), but no subgroup showed significant correlation with any clini-cal parameter. Renal cortical scars detected by follow-up CT were more prevalent in patients in whom initial CT demonstrated the presence of an abscess. CONCLUSION: Clinical parameters correlated with the presence of renal parenchymal hypoenhancing lesions and abscess formation, as seen on CT scans, rather than the number of renal parenchymal lesions. Renal cortical scars were more prevalent in patients in whom initial CT revealed the presence of an abscess. Enhanced CT is thought to be useful both for diagnosing APN and for predicting its clinical course in children.

Radiological Findings after Endoscopic Incision of Ureterocele

PURPOSE: Endoscopic incision of ureterocele is considered a simple and safe method for decompression of urinary tract obstruction above ureterocele. The purpose of this study was to evaluate the radiological findings after endoscopic incision of ureterocele. MATERIALS AND METHODS: We retrospectively reviewed the radiological findings ultrasonography (US), intravenous urography, and voiding cystourethrography(VCU)] in 16 patients with ureterocele who underwent endoscopic incision (mean age at surgery, 15 months; M: F=3:13; 18 ureteroceles). According to the postoperative results, treatment was classified as successful when urinary tract obstruction improved without additional treatment, partially successful when medical treatment was still required, and second operation when additional surgical treatment was required. RESULTS: Postoperative US (n=10) showed that in all patients, urinary tract obstruction was relieved: the kidney parenchyma was thicker and the ureterocele was smaller. Intravenous urography (n=8), demonstrated that in all patients, urinary tract obstruction and the excretory function of the kidney had improved. Postoperative VCU indicated that in 92% of patients (12 of 13), endoscopic incision of the ureterocele led to vesicoureteral reflux(VUR). Of these twelve, seven (58%) showed VUR of more than grade 3, while newly developed VUR was seen in five of eight patients (63%) who had preoperative VCU. Surgery was successful in four patients (25%), partially successful in three (19%), and a second operation-on account of recurrent urinary tract infection and VUR of more than grade 3 during the follow-up period was required by nine (56%). CONCLUSION: Although endoscopic incision of a ureterocele is a useful way of relieving urinary tract obstruction, an ensuing complication may be VUR. Postoperative US and intravenous urography should be used to evaluate parenchymal change in the kidney and improvement of urinary tract obstruction, while to assess the extent of VUR during the follow-up period, postoperative VCU is required.

Which are Risk Factors developing Renal Cortical Defects on 99 mTc - DMSA Scintigraphy in Children with Acute Urinary Tract Infections?

PURPOSE: To determine (1) the relationship between the cortical defects seen on 99 mTc-DMSA renal scans and age, and (2) the presence and degree of vesicoureteral reflux, and then to depict the risk factors for cortical defects in children with acute urinary tract infection (UTI). Furthermore, to assess the diagnostic value of VCUG in predicting a defect on 99 mTc-DMSA renal scans. MATERIALS AND METHODS: We studied 134 kidneys in 67 children aged 15 days-10 years (M:F=39:28) in whom symptomatic UTI was present. In all these children, both DMSA renal scans and voiding cystourethrography (VCUG) were performed. Scanning took place within 7 days of diagnosis and VCUG was performed after one month of diagnosis. Scintigraphic findings were graded according to the extent and number of cortical defects. We evaluated the relationships between the cortical defects seen on DMSA scans and age, and the grade of vesicoureteral reflux. The diagnostic value of VCUG in predicting cortical defects was analysed. Results: The prevalence of cortical defects was greater in patients older than two years (38/54, 70%) than in those aged less than two (38/80, 48%). The frequency of cortical defects was related to vesicoureteral reflux (p or =2yrs) at the time of acute UTI, and high grade of vesicoureteral reflux. The specificity of VCUG in predicting cortical defects is relatively high but the sensitivitiy is low, and a significant proportion of cortical defects therefore occurred in the absence of vesicoureteral reflux.

Imaging Features of Rhabdoid Tumor of the Kidney in Children

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.

Imaging Features of Rhabdoid Tumor of the Kidney in Children

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.

MRI for the Detection of Ureteral Opening and Ipsilateral Kidney in Children with Single Ectopic Ureter

PURPOSE: To assess the usefulness of MRI in the detection of a single ectopic ureteral opening and thelocation and dysplastic change of ipsilateral kidney. MATERIALS AND METHODS: Nine patients (mean age; 4.8 years,M:F=3:6) in whom a single ectopic ureter was suspected clinically and sonographically underwent conventionalradiologic studies ( IVP, VCUG, 99mTc-DM-SA scan, as well as US) and MRI. We evaluated images of the point of theectopic ureteral opening and the location and dysplastic or hydronephrotic change of the ipsilateral kidney, andcompared those findings with the endoscopic, surgical, and pathological findings. RESULTS: Eight patients had aunilateral single ectopic ureter and one had bilateral lesions. Seven normally positioned kidneys in six patientsshowed dysplastic (n=3) or hydronephrotic (n=4) change. In two patients an ectopic dysplastic kidney was locatedin the pelvis and one had ipsilateral renal agenesis. Conventional radiologic studies failed to reveal twoectopic dysplastic kidneys, one renal agenesis, and eight ectopic ureteral openings. In all patients, MRI clearlydemonstrated the location of the kidney and ectopic ureteral opening, and dysplastic or hydronephrotic change ofthe kidney, and in one patient, uterine duplication. Except in two patients whose ectopic ureteral opening was notfound on endoscopy, MRI findings were concordant with endoscopic and surgical findings. CONCLUSION: MRI wasuseful for the detection of a single ectopic ureteral opening and for demonstrating the location and dysplasticchange of ipsilateral kidney.

CT of Acute Pyelonephritis in Children: Comparison with Tc-99m DMSA Scintigraphy

PURPOSE: The purpose of the study was to compare CT with scintigraphy in the detection of parenchymal lesionsof acute pyelonephritis in children, and to assess the diagnostic value of CT. MATERIALS AND METHODS: This studyinvolved 32 children with acute pyelonephritis ; their ages ranged from 1 month to 10 years. Renal CT , TC-99mDMSA planar and SPECT images, and medical records were retrospectively reviewed. We evaluated the number, size,shape, density, and location of pyelonephritic lesions, as seen on CT and scintigraphic images. RESULTS: In 43involved kidneys, 193 parenchymal lesions of acute pyelonephritis were identified. The results of CT were abnormalin 42 kidneys (98%), and those of scintigraphy, in 39(91%). CT showed single or multiple hypoenhancing parenchymallesions ; these were streaky(n=151), wedge-shaped (n=34), or oval (n=8), and ranged from about 3-30mm in maximumdiameter. Abscess (n=5), renal fascial thickening (n=6) and thickening of the bridging septae (n=7) wereassociated. Scintigraphic findings were diffuse or localized area of varying degrees of diminished corticalactivity, and these were more precisely identified on SPECT than on planar images. For the detection of 55 of 193pyelonephritic lesions, CT was more sensitive than scintigraphy ; 29 of the 55 lesions were less than 5 mm indiameter. CONCLUSION: For the detection of pyelonephritic lesions, particularly smaller ones, and for theevaluation of complications such as abscess formation, CT is more sensitive than Tc-99m DMSA scintigraphy. Weconclude that in children with subtle scintigraphic findings who are in serious clinical condition or in whomcomplications are suspected, CT is a useful tool for assessing a therapeautic plan and the prognosis of acutepyelonephritis.

Fused Cake Kidney Combined with Hypoplastic Thumb: A Case Report

During embryologic development, many renal anomalies, including fusion and ectopia, can occur. Among them, fused cake kidney is a rare developmental anomaly. We report a case in which this condition was combined with hypoplastic thumb. Ultrasonographic, scintigraphic, CT and MRI findings of this rare condition are presented.

Comparison of Needle Size in Pediatric Renal Biopsy with Sono-Guided Percutaneous Automated Gun Technique

PURPOSE: To compare the efficacy of a 20-gauge and an 18-gauge needle in sono-guided percutaneous automated gun biopsy for establishing the specific diagnosis of renal parenchymal disease in pediatric kidneys. MATERIALS AND METHODS: In 60 pediatric patients with renal parenchymal diseases, percutaneous sono-guided gun biopsy was performed by an experienced radiologist. In two groups of 30 patients, regardless of their age, two needle passes were performed, using alternately an 18-gauge or a 20-gauge biopsy needle. The core of renal tissue thus obtained was examined with light, immunofluorescent or electron microscopy by the renal pathologist. The mean number of intact glomeruli of whole tissue core per biopsy, as seen on the light microscopy, and post-bioptic complications were compared between the two different needle size groups. RESULTS: The number (mean+/-1 standard deviation) ofglomeruli obtained per biopsy was 17+/-8 in the 18-gauge needle group, and 14+/-5 in the 20-gauge group. Between two groups, there was no major post-bioptic complication requiring specific treatment, nor a statistically significant difference in the frequency of minor complications. CONCLUSION: Even though more glomeruli were obtained with an 18-gauge needle, the number obtained with a 20-gauge needle also permitted adequate pathologic examination. Both an 18-gauge and a 20-gauge needle may thus be suitable for renal biopsy in pediatric patients.