Gregor Novljan

Echo-enhanced ultrasound voiding cystography in children: a new approach

Abstract The development of echo-enhancing agents has significantly improved the detection of the movement of fluid within the urinary tract by ultrasonography (US). The purpose of our study was to compare ultrasound voiding cystography (USVC) for the detection of vesicoureteric reflux (VUR) in children with direct radionuclide voiding cystography (DRVC). Ninety-nine children, aged 1.1–12.3 years, with 198 potentially refluxing units, were investigated simultaneously by DRVC and USVC. The indications for cystography were urinary tract infection, follow-up of a previously detected VUR, and screening of siblings of children with VUR. During the investigation an echo-enhancing agent (Levovist) was administered intravesically through a catheter already in place for the DRVC. The movement of both agents, radiotracer and Levovist, was registered simultaneously by a computerized gamma camera and US, respectively. The results were analyzed with DRVC representing the reference diagnostic test. The overall sensitivity and specificity of USVC for the detection of VUR were 79% and 92%, respectively. USVC may represent a reliable diagnostic tool for the detection and follow-up of VUR in children.

Demographics of blood pressure and hypertension in children on renal replacement therapy in Europe

Hypertension is a well-known complication in children on renal replacement therapy and an important risk factor for cardiovascular disease in later life. In order to define the prevalence of and risk factors for hypertension among children, we enrolled 3337 pediatric patients from 15 countries in the ESPN/ERA-EDTA Registry of whom 464 were on hemodialysis, 851 on peritoneal dialysis, and 2023 had received a renal allograft. Hypertension was defined as either systolic or diastolic blood pressures in the 95th percentile or greater for age, height, and gender or use of antihypertensive medication. Analyses were adjusted for age, gender, duration, and modality of renal replacement therapy. In 10 countries in which information on the use of antihypertensive medication was available, hypertension was present in over two-thirds of hemodialysis, peritoneal dialysis, or transplant patients. Blood pressure values above the 95th percentile were significantly more prevalent in very young patients (under 3 years) compared to 13- to 17-year olds (odds ratio 2.47), during the first year compared to over 5 years of renal replacement therapy (odds ratio 1.80), and in patients on hemodialysis compared to transplant recipients or those on peritoneal dialysis (odds ratios of 2.48 and 1.59, respectively). Over time, mean blood pressures decreased in both hemodialysis and transplant patients, but not in peritoneal dialysis patients. Hence, our findings highlight the extent of the problem of hypertension in children with end-stage renal disease in Europe.

Determinants of eGFR at start of renal replacement therapy in paediatric patients

BACKGROUND Few studies have investigated the determinants of glomerular filtration rate (GFR) in paediatric patients starting on dialysis or with a transplant. METHODS Data were collected as part of the European Society of Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association registry from 14 European countries and referred to incident paediatric patients starting on renal replacement therapy (RRT) between 2002 and 2007 under the age of 18 years. Estimated glomerular filtration rate (eGFR) was calculated using the Schwartz formula. Data were adjusted for age, gender, treatment modality at start, primary cause of renal failure (PRD) and regions in Europe (eGFR(adj)). RESULTS Median eGFR in the 938 patients starting RRT was 10.4 mL/min/1.73 m(2) (5th and 95th percentile: 4.0-26.9). Twenty-six patients (2.8%), mainly infants with Finnish-type nephropathy, started with eGFR levels >50 mL/min/1.73 m(2). Younger age, female gender, starting on dialysis and having a short time between the first visit to a paediatric nephrologist (PN) and start of RRT were associated with lower eGFR at start of RRT. Gender differences were only present during adolescent age and disappeared when using the same K value for both genders. The various PRDs showed large differences in the rate of decline in eGFR between the first visit to a PN and start of RRT; however, this did not result in differences in eGFR(adj) at start of RRT. CONCLUSIONS The main determinants of eGFR at start of RRT were age, gender, treatment modality at start, and the time between the first visit to a PN and start of RRT. Research is needed to determine the consequences of these differences.

Ultrasound Detection of Vesicoureteral Reflux in Children

PURPOSE We present different ultrasound techniques to detect vesicoureteral reflux in children with special emphasis on voiding urosonography. MATERIALS AND METHODS Urinary tract infection is a common problem in children that may be related to vesicoureteral reflux. Currently there is no consensus on investigations in children after the first urinary tract infection. The least invasive imaging with the smallest radiation burden should be used in children. Ultrasound to detect reflux meets several of these criteria. The development of echo enhancing agents has markedly improved reflux visualization by ultrasound. RESULTS We discuss the clinical relevance of voiding urosonography. We reviewed the currently available literature and the results of our studies of this issue. We also describe our endeavors to avoid catheterization and detect vesicoureteral reflux based on various sonomorphological features, ie indirect voiding urosonography and ureteral jet Doppler waveform analysis, to avoid applying any substance into the bladder. CONCLUSIONS Voiding urosonography is safe and reliable to detect vesicoureteral reflux. When indicated, considerably decreased radiation exposure can be achieved by voiding urosonography instead of established cystography methods. Indirect voiding urosonography and ureteral jet Doppler waveform analysis could be an alternative to invasive voiding cystography, at least in children older than 3 years.

Vascular access in children on chronic hemodialysis: a Slovenian experience.

The aim of our study was to report our experience with arteriovenous fistulas (AVFs) and non‐cuffed central venous catheters (CVCs) in children and adolescents with end‐stage renal disease (ESRD) on hemodialysis (HD). The children with ESRD (18 years or younger) who were hemodialyzed at the Center of Dialysis and Transplantation, Childrens Hospital, Ljubljana, in the period between December 1998 and December 2010 were included in our retrospective study. We recorded the data considering the CVCs and AVFs used for HD. Thirty‐one children (13 females, 18 males) with ESRD received HD treatment. The mean patient age when HD was started was 13.3 ± 3.4 years. Altogether, 35 AVFs were created, and the primary failure rate was 25.7% (9/35). The time to maturation was 4.0 ± 2.5 months. The mean patency of the AVF was 42.5 ± 51.9 months. Seventy‐seven CVCs (non‐cuffed) were inserted in the observation period; 89.6% of the CVCs were inserted in the jugular vein, and citrate locking was used in the interdialysis period. The CVCs were removed after 0.1–17.4 months (3.6 ± 3.7 months). The incidence of bacteremia was 0.9 episodes per 1000 catheter days. The preferred vascular accesses for pediatric hemodialysis are native AVFs; however, a single lumen, non‐cuffed, citrate‐locked CVC placed in a jugular vein can be acceptable as a long‐term vascular access when AVF cannot be constructed or used.

Detection of Dialysis Access Induced Limb Ischemia by Infrared Thermography in Children

High arteriovenous fistula (AV fistula) blood flow may impair distal limb perfusion and cause irreversible ischemic damage. Since tissue temperature reflects blood perfusion, we tried to assess distal blood flow using an infrared camera. We examined all 12 patients with an AV fistula in our dialysis unit. Seven were pediatric patients aged 11.0–18.9 years (mean 14.9 years) and five were adults aged 26.9–62.1 years (mean 38.6 years). Infrared thermal imaging (thermography) of their hands was performed after the completion of their regular dialysis sessions. In each patient, the spot temperature of each fingertip on both hands was assessed separately, with three measurements being performed for each measuring point. The mean spot temperature of all fingertips was calculated for each hand and the results compared. A statistically significant difference (P < 0.05) indicated distal perfusion insufficiency. Perfusion of the hands was also assessed by inspecting the visualized temperature distribution on the thermal image. Finally, we compared the results to the clinical findings in relevant patients. In 8/12 patients (66.7%), the mean spot temperature of the fingertips was statistically significantly lower on the fistula side (P < 0.05). Only 4/12 patients (33.3%) had clinical symptoms, and all were detected by thermography. Abnormal findings were more frequent in elderly patients. Although we realize that the diagnosis of steal syndrome is primarily clinical, thermography might be a safe, noninvasive, cheap tool for the timely detection of children at risk of developing symptoms of hand ischemia.

Catheter-free methods for vesicoureteric reflux detection: our experience and a critical appraisal of existing data

In recent years, the exact role of vesicoureteric reflux (VUR) in general has become controversial, though in some groups of children the knowledge of the existence or non-existence of VUR is still a very important issue. The number of techniques available for the assessment of VUR is increasing, and a new classification taking into account their real characteristics (direct/indirect, catheter-using/catheter-free, radiation-giving/radiation-free) has been proposed. The purpose of the following review is to evaluate the currently available evidence supporting the use of various catheter-free methods for VUR detection. We believe that as the clinical role of VUR has been questioned, it is even more important for the method of its detection to be user-friendly as regards catheterisation, radiation and availability. There is still no evidence supporting the assertion that any of the catheter-free methods of VUR detection might be the optimal one for any child. However, there are some groups of children who would benefit from using them. New studies using new, catheter-free methods of VUR detection or a combination of two or more of the methods described may prove useful in improving sensitivity and providing additional data on this important issue.

Chronic Hemodialysis in Small Children.

When peritoneal dialysis is inapplicable, chronic hemodialysis (HD) becomes the only available treatment option in small children. Due to small patient size, central venous catheters (CVC) are mainly used for vascular access. Over the past 4 years, four children weighing less than 15 kg received chronic HD in our unit. A total of 848 dialysis sessions were performed. Altogether, 21 catheters were inserted. In all but one occasion, uncuffed catheters were used. Catheter revision was performed 15 times during the study period, either due to infection or catheter malfunction. The median number of catheter revisions and the median line survival was 3.0/patient‐year and 53 days (range; 6–373 days), respectively. There were 14 episodes of catheter related infections requiring 11 CVC revisions (78.6%). The median rate of line infections was 2.8/patient‐year. Chronic HD in small children is demanding and labor intensive. Issues pertain mainly to CVCs and limit its long‐term use.

End-Stage Renal Disease in an Infant With Hajdu-Cheney Syndrome

Hajdu‐Cheney syndrome (HJCYS) is a rare, autosomal dominant, skeletal disorder caused by mutations in the NOTCH2 signaling pathway for which genetic testing has recently become available. Renal abnormalities are associated in at least 10% of cases. We present an 8‐year‐old Caucasian boy, born with multiple dysmorphic features consistent with HJCYS. Imaging of the urinary tract revealed bilateral cystic dysplastic kidneys with associated vesicoureteral reflux. Renal function has been impaired since birth and deteriorated progressively to end‐stage renal disease (ESRD) by the age of two and a half years, when peritoneal dialysis was initiated and only recently renal transplantation was performed. Additional congenital abnormalities and multisystem involvement in HJCYS further complicated management, and he developed refractory anemia. Molecular diagnosis was confirmed by identification of a truncating mutation in exon 34 of NOTCH2. Although, renal abnormalities are considered an integral part of the HJCYS, published reports on ESRD are scarce. In those few published cases, where ESRD was recognized, renal failure developed either in late adolescence or adulthood. This is the first report of early ESRD occurring in a child. Patients with HJCYS may need chronic renal replacement therapy even in early childhood. The management of these children can be challenging given the multisystemic manifestations of HJCYS.

Renal Replacement Therapy in Slovenia: Excerpts From 2011 Data

This report provides a summary of the 2011 Slovenian renal replacement therapy (RRT) data. Data were obtained from 24 renal centers: 23 dialysis and one transplant center, referred as of 31 December 2011, with 100% response rate to individual patient questionnaires. Slovenia has a population of approximately 2 million (2 052 496 in 2011). The total number of patients treated by RRT was 2011,that is, 980 per million of population (pmp); 0.4% decrease compared to 2010. 1347 (67.0%) were treated by hemodialysis, 60 (3.0%) by peritoneal dialysis, and 604 (30.0%) had a functioning kidney graft. A total of 236 incident patients, 115 pmp (at day one), started RRT, their median age was 68 years, 64.8% were men, 36.4% were diabetics. Regarding hemodialysis patients, 59.3% were treated with on‐line hemodiafiltration, 86% with ultrapure dialysis fluid. Median weekly duration of hemodialysis was 12.5 h, median dry body weight 70 kg, mean blood flow 275 ± 46 mL/min, 7.1% were dialyzed in a single‐needle mode. Vascular accesses were native arteriovenous fistula in 79%, polytetrafluoroethylene graft in 6%, and catheter in 15%. The crude death rate was 15.9% in dialysis patients, 1.9% in transplant recipients, and 12.0% in all RRT patients (both dialysis and transplant, incident patients at day 1 included). Slovenia has been a member of Eurotransplant since 2000. Forty‐six kidney transplantations were performed in 2011, all from deceased donors. A slight decrease in prevalent number of RRT patients was observed in 2011, for the first time in 40 years. The number and proportion of patients with functioning kidney grafts is increasing, reaching 30% in 2011.