Day- and night-time blood pressure elevation in children with higher grades of renal scarring

Yield of diagnostic testing in evaluating etiology and end organ effects of pediatric hypertension

BACKGROUND

Current recommendations regarding the utility of diagnostic investigations for pediatric hypertension are based on limited evidence, leading to wide practice variation. The objective of this study was to characterize the cohort of children that may benefit from secondary hypertension workup, and determine the diagnostic yield of investigations.

METHODS

This was a single-center, retrospective cohort study of 169 children aged 1-18 years referred between 2000 and 2015, to a tertiary pediatric nephrology center in Canada, for evaluation of hypertension. The number of investigations completed, abnormal findings, and diagnostic findings that helped establish hypertension etiology was determined.

RESULTS

56 children were diagnosed with primary and 72 children with secondary hypertension in the outpatient setting. Secondary hypertension was predominant at all ages except for obese adolescents ≥ 12 years. Half of children with traditional risk factors for primary hypertension, including obesity, were diagnosed with secondary hypertension. Kidney ultrasound had the highest yield of diagnostic results (19.8%), with no difference in yield between age groups (P = 0.19). Lipid profile had a high yield of abnormal results (25.4%) as part of cardiovascular risk assessment but was only abnormal in overweight/obese children. Echocardiogram had a high yield for identification of target-organ effects in hypertensive children (33.3%).

CONCLUSION

A simplified secondary hypertension workup should be considered for all hypertensive children and adolescents. High yield investigations include a kidney ultrasound, lipid profile for overweight/obese children, and echocardiograms for assessment of target-organ damage. Further testing could be considered based on results of initial investigations for the most cost-effective management. A higher resolution version of the Graphical abstract is available as Supplementary information.

Masked Hypertension in Healthy Children and Adolescents: Who Should Be Screened?

PURPOSE OF REVIEW

The goal is to review masked hypertension (MH) as a relatively new phenomenon when patients have normal office BP but elevated out-of-office BP. Firstly, it was described in children in 2004. It has received increased attention in the past decade.

RECENT FINDINGS

The prevalence of MH in different pediatric populations differs widely between 0 and 60% based on the population studied, definition of MH, or method of out-of-office BP measurement. The highest prevalence of MH has been demonstrated in children with chronic kidney disease (CKD), obesity, diabetes, and after heart transplantation. In healthy children but with risk factors for hypertension such as prematurity, overweight/obesity, diabetes, chronic kidney disease, or positive family history of hypertension, the prevalence of MH is 9%. In healthy children without risk factors for hypertension, the prevalence of MH is very low ranging 0-3%. In healthy children, only patients with the following clinical conditions should be screened for MH: high-normal/elevated office BP, positive family history of hypertension, and those referred for suspected hypertension who have normal office BP in the secondary/tertiary center.

The ureteral diameter ratio as a predictive factor in renal scarring associated with primary vesicoureteral reflux

INTRODUCTION

The ureteral diameter ratio (UDR) is reported to be effective in predicting the outcomes of vesicoureteral reflux (VUR) in several studies.

OBJECTIVE

The objective of the current study was to compare the risk of scarring in patients with VUR relative to UDR and the VUR grade. We also aimed to demonstrate other associated risk factors in scarring and investigate the long-term complications of VUR and their relationship with UDR.

STUDY DESIGN

Patients diagnosed with primary VUR were retrospectively enrolled in the study. UDR was calculated by dividing the largest ureteral diameter (UD) by the distance between L1-L3 vertebral bodies. Demographic and clinical data, laterality, VUR grade, UDR, delayed upper tract drainage on voiding cystourethrogram, recurrent urinary tract infections (UTI), and long-term complications of VUR were compared between the patients with and without renal scars.

RESULTS

A total of 127 patients and 177 renal units were included in the study. There was a significant difference between the patients with and without renal scars according to age at diagnosis, bilaterality, reflux grade, UDR, recurrent UTI, bladder bowel dysfunction, hypertension, decreased estimated glomerular filtration rate, and proteinuria. The logistic regression analysis revealed that UDR had the highest odds ratio among the factors affecting scarring in VUR.

DISCUSSION

VUR grading based on the evaluation of the upper urinary tract is one of the most important predictors for treatment options and prognosis. However, it is more likely to reflect ureterovesical junctional anatomy and function, which play a crucial role in the pathogenesis of VUR.

CONCLUSION

UDR measurement seems to be an objective method that can help clinicians predict renal scarring in patients with primary VUR.

Functional constipation as a risk factor for pyelonephritis and recurrent urinary tract infection in children

AIM

Acute pyelonephritis is one of the most common bacterial infections in childhood. This potentially serious condition can lead to renal scarring, loss of kidney function and hypertension. The aim of this study was to identify risk factors associated with pyelonephritis in children without kidney or urinary tract abnormalities.

METHODS

Medical records of children aged 4-18 diagnosed with 1st time pyelonephritis from 2016 to 2021 were retrospectively analysed. Children with abnormal kidney ultrasound were excluded. In addition to demographic data, information on bladder and bowel function was extracted together with habits of fluid intake.

RESULTS

A total of 105 patients were diagnosed with 1st time pyelonephritis. Of these, 47% were diagnosed with constipation according to the Rome IV criteria within a mean follow-up period of 167 days after their pyelonephritis, which is markedly higher than the estimated prevalence of constipation in the background population. Constipation was positively associated with recurrent urinary tract infection (p = 0.01).

CONCLUSION

Constipation is associated with pyelonephritis and recurrent urinary tract infection in children (primarily girls) 4-18 years of age without evident kidney or urinary tract abnormalities. We recommend systematic evaluation of bowel and bladder function after 1st time pyelonephritis in all children >4 years.

Isolated nocturnal hypertension in pediatric kidney transplant recipients

BACKGROUND

Isolated nocturnal hypertension (INH) is defined as nighttime hypertension in the setting of normal daytime blood pressure (BP), diagnosed by ambulatory BP monitoring (ABPM).

METHODS AND RESULTS

Hypertension affects 60%-80% of pediatric kidney transplant recipients, and INH is the most common type of ambulatory hypertension. INH is associated with an increased prevalence of hypertension-mediated target organ damage such as left ventricular hypertrophy in adults and in pediatric kidney transplant recipients.

CONCLUSION

Ambulatory BP monitoring should be performed annually in all pediatric kidney transplant recipients to diagnose hypertension phenotypes that are not detectable by office BP such as masked hypertension, white-coat hypertension, or INH. Isolated nocturnal hypertension in pediatric transplant patients requires study as a treatment target.

Risk factors for kidney scarring and vesicoureteral reflux in 421 children after their first acute pyelonephritis, and appraisal of international guidelines

BACKGROUND

Acute pyelonephritis (AP) is a common bacterial infection in childhood. Follow-up guidelines on these children are controversial. This study aimed to identify risk factors for kidney scarring and vesicoureteral reflux (VUR). Furthermore, international follow-up guidelines were used for simulation to evaluate sensitivity and specificity.

METHODS

Urinary culture-confirmed first-time AP patients (aged 0-14 years) were enrolled (n = 421) from review of patient charts. All underwent kidney ultrasound (US) and a technetium-99m-dimercaptosuccinic acid (DMSA) scan or technetium-99m-mercaptoacetyltriglycine scinti-renography (MAG3) at 4-6 months of follow-up. The international guidelines used for simulation were from the National Institute of Health UK (NICE), the American Association of Paediatrics (AAP) and the Swedish Paediatric Society (SPS).

RESULTS

17.8% presented with an abnormal DMSA/MAG3 at follow-up, 7.1% were diagnosed with VUR grades III-V and 4.7% were admitted for surgery. Non-Escherichia coli infections, abnormal kidney US, elevated creatinine and delayed response to treatment (>48 h) were risk factors for abnormal DMSA findings and VUR grades III-V. NICE and SPS guidelines showed best sensitivity in diagnosing VUR grades III-V (75%) compared with AAP (56%).

CONCLUSIONS

Risk factors are helpful in identifying the children in need of further investigations and minimizing invasive work-up for the rest. International guidelines on follow-up detect a varying number of children with kidney damage and/or significant VUR. Future work must focus on identifying more specific risk factors, better imaging, or specific biomarkers, to enhance sensitivity and specificity in detecting the children at high risk for developing recurrent infections and/or nephropathy.

Isolated nocturnal hypertension is associated with increased left ventricular mass index in children

BACKGROUND

Isolated nocturnal hypertension (INH) is associated with increased prevalence of left ventricular hypertrophy (LVH) and cardiovascular morbidity and mortality in adult patients. Unlike in adults, data illustrating the possible association between INH and cardiac target organ damage is lacking in children. This study aimed to investigate whether INH is associated with increased left ventricular mass index (LVMI) and LVH in children.

METHODS

Retrospective data from all untreated children with confirmed ambulatory hypertension (HT) in our center was reviewed. Ambulatory blood pressure monitoring (ABPM) and echocardiography were performed concurrently. Ambulatory normotensive children served as controls. LVH was defined as LVMI ≥ 95th percentile.

RESULTS

There were 102 ABPM studies; of these, 79 children had renal HT, and 23 had primary HT. Median age of children was 13.2 years (3.8-18.9). Nineteen children had INH, 9 children had isolated daytime HT, 54 had daytime and nighttime HT, and 20 were normotensive. The LVMI adjusted for age (patient's LVMI/95th percentile of the LVMI) was significantly higher in children with INH than in normotensive children (0.83 ± 0.03 vs. 0.74 ± 0.03, p = 0.03). Left ventricular hypertrophy was present in 11% of children with INH; this was not significantly higher than in normotensive children (0%, p = 0.23).

CONCLUSIONS

This study investigated the association between INH and cardiac structure in children with primary and renal HT and showed children with INH had higher LVMI adjusted for age than normotensive children and children with INH had similar LVMI adjusted for age to children with isolated daytime HT.

Predictive factors for bacteremia in febrile infants with urinary tract infection

This study aimed to investigate the predictive factors of concomitant bacteremia occurring in febrile infants who initially presented with pyuria and fever, and were subsequently diagnosed with culture-proven urinary tract infection (UTI). We conducted a retrospective cohort study for January 2010–October 2018 that included infants younger than six months with febrile UTI at a tertiary hospital. The study included 463 patients, of whom 34 had a concomitant bacteremic UTI. Compared to those in the non-bacteremic urinary tract infection (UTI) group, the bacteremic UTI group had a lower mean age; higher levels of C-reactive protein (CRP), delta neutrophil index (DNI, reflects the fraction of immature granulocytes) and blood urea nitrogen (BUN); lower levels of hemoglobin (Hb) and albumin; and a lower platelet count. Vesicoureteral reflux (VUR) was detected nearly twice as often in patients with bacteremic UTI compared to those with non-bacteremic UTI (59.3% vs. 30.6%; P = 0.003). Univariate logistic analyses showed that age ≤90 days; higher DNI, CRP, and creatinine levels; lower Hb and albumin levels; and the presence of VUR were predictors for bacteremic UTI. On multivariate logistic regression analysis, age ≤90 days, higher DNI and CRP levels, and the presence of VUR were independent predictors of bacteremic UTI. The area under the receiver operating characteristic curve of the multivariate model was 0.859 (95% CI, 0.779–0.939; P < 0.001). Age ≤90 days, higher DNI and CRP values may help predict bacteremia of febrile infants younger than 6 months with UTI. Vesicoureteral reflux imaging is also recommended in infants with bacteremic UTI to evaluate VUR.

Changing prevalence and antibiotic drug resistance pattern of pathogens seen in community-acquired pediatric urinary tract infections at a tertiary care hospital of North India

AIMS AND OBJECTIVES

The aim and objective of this study was to assess the temporal changes in the microbiological profiles and antimicrobial resistance patterns of uropathogens in pediatric community-acquired UTI.

MATERIALS AND METHODS

This is a retrospective analysis of data collected over a Scattered period of 5 years. The baseline data collected were from January to December 2009, and the second period considered for comparison was from January to December 2014. Urine specimens from children (<17 years) suspected of UTI were cultured by a semi-quantitative method on cysteine lactose electrolyte-deficient medium. Antibiotic sensitivity was put up by Kirby-Bauer disc diffusion method as per the Clinical and Laboratory Standard Institute guidelines.

RESULTS

In the year 2009, 340 of 2104 (16.15%) urine specimens yielded significant colony count, whereas in 2014, it was 407 of 2212 (18.39%) (P = 0.051). Escherichia coli was the predominant pathogen and was significantly more prevalent in girls than in boys (P < 0.0001) during both periods. There was a significant overall increase in resistance to ampicillin (from 40.29% to 58.72%), amoxyclav (from 26.17% to 40.54%), nitrofurantoin (from 28.82% to 39.06%), and norfloxacin (from 30% to 41.42%). However, the maximum increase in the resistance was noted for co-trimoxazole from 35.58% in 2009 to 63.39% in 2014 (P = 0.0000058). The prevalence of extended-spectrum beta-lactamases (ESBLs) has also significantly increased from 21.7% to 33.16% (P = 0.0045).

CONCLUSION

Although E. coli remains the prime pathogen in pediatric UTI, the prevalence of resistance has dramatically increased over the 5-year study period. Our study highlights the emergence of community-acquired ESBL-producing uropathogens in children proclaiming treatment challenges.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

[Imaging in urinary tract infections in childhood]

Diagnostic strategies for extended morphological and functional clarification after symptomatic urinary tract infections in children are changing. Improved knowledge of the causes for development of renal scarring and a changing view on the importance of vesicoureteral reflux have led to a change in paradigm in recent years. The purpose of this article is to present the ongoing discussions of the causes and outcome of childhood urinary tract infections, competing diagnostic imaging methods and different diagnostic algorithms.

Urinary tract infection in small outpatient children: the influence of age and gender on resistance to oral antimicrobials

Urinary tract infection (UTI) is a common bacterial disease in small children in which treatment with antimicrobials is used. The worldwide increase of bacterial resistance to these drugs is threatening the efficacy of such treatment and may increase the risk for long-term damage. The aim of this retrospective study was to analyse the development of resistance to oral antimicrobials over a 10-year period in an unselected outpatient population of small children with first-time UTI. The patient material included 494 boys and 512 girls below 2 years of age with community acquired symptomatic UTI. Escherichia coli bacteria were isolated in 96 % of girls and 89 % of boys (p < 0.0001). The overall resistance of E. coli was 14 % to trimethoprim and below 1 % to cefadroxil and nitrofurantoin. Over the 10-year period, the trimethoprim resistance of E. coli increased from 5 to 17 % but remained unchanged to cefadroxil and nitrofurantoin. E. coli resistance to trimethoprim was related to age: 11 % below and 19 % above 9 months (p < 0.01). The increase in resistance over time and with age was found only in girls.

CONCLUSION

The increasing resistance of E. coli to trimethoprim makes this drug less suitable for empiric treatment of UTI. Young children with UTI seem predisposed to early development of resistance. Therefore, surveillance of resistance to antimicrobials with special regard to age and gender is recommended.

Different imaging strategies in febrile urinary tract infection in childhood. What, when, why?

Urinary tract infections (UTIs) are a common problem in childhood. During the last decade, published papers led to a deep revision in the use and usefulness of imaging tools in children with febrile UTIs. This new body of knowledge was partially endorsed by the guidelines published in 2007 by the UK's National Institute for Clinical Excellence and in 2011 by the American Academy of Pediatrics. Nevertheless, new data continuously arise and the scientific debate always revives. Recommendations of published guidelines and strengths and weaknesses of the available biochemical and imaging tools are here critically analysed for giving to the reader a complete, up-to-date and flexible overview on this hot topic.

Altered cardiovascular rhythmicity in children born small for gestational age

Low birth weight is frequently associated with a disproportionately high incidence of cardiovascular disease, diabetes mellitus, and kidney disease in adulthood. Epidemiological studies have identified an inverse association between low birth weight or being small for gestational age and hypertension in adulthood. We hypothesized that children born with low birth weight might have altered circadian and ultradian cardiovascular rhythmicity independent of the prevailing blood pressure level. Twenty-four-hour ambulatory blood pressure and heart rate rhythmicity was prospectively evaluated by Fourier analysis in a cohort of healthy children born with low birth weight and compared with normative pediatric data. Seventy-five children born small for gestational age (mean age, 8.1±2.2 years) and 139 controls matched for age and sex were investigated. In addition to increased 24-hour, daytime, and especially nighttime blood pressure levels (P<0.05), children born small for gestational age exhibited blunted circadian (24-hour) and ultradian (12-, 8-, and 6-hour) blood pressure rhythmicity (P<0.05). In a multivariate analysis including children born with low birth weight and controls, being born with low birth weight independently influenced ultradian blood pressure rhythmicity, whereas in a multivariate analysis including children born with low birth weight only, circadian and ultradian rhythms were independently influenced by catch-up growth, gestational age, and blood pressure level. This study demonstrates blunted circadian and ultradian cardiovascular rhythmicity in prepubertal children born small for gestational age, independent from the presence of arterial hypertension. Circadian and ultradian rhythms may be sensitive indicators for detecting subtle early abnormalities of cardiovascular regulation.

Pediatric ambulatory blood pressure monitoring: indications and interpretations

The prevalence of hypertension in children and adolescents is increasing, especially in obese and ethnic children. The adverse long-term effects of hypertension beginning in youth are known; therefore, it is important to identify young patients who need intervention. Unfortunately, measuring blood pressure (BP) is difficult due to the variety of techniques available and innate biologic variation in BP levels. Ambulatory BP monitoring may overcome some of the challenges clinicians face when attempting to categorize a young patient's BP levels. In this article, the authors review the use of ambulatory BP monitoring in pediatrics, discuss interpretation of ambulatory BP monitoring, and discuss gaps in knowledge in usage of this technique in the management of pediatric hypertension.

Adjunctive oral methylprednisolone in pediatric acute pyelonephritis alleviates renal scarring

OBJECTIVE

To determine if glucocorticoids can prevent renal scar formation after acute pyelonephritis in pediatric patients.

METHODS

Patients younger than 16 years diagnosed with their first episode of acute pyelonephritis with a high risk of renal scar formation (ie, inflammatory volume ≥ 4.6 mL on technetium-99m-labeled dimercaptosuccinic acid scan [DMSA] or abnormal renal ultrasonography results) were randomly assigned to receive either antibiotics plus methylprednisolone sodium phosphate (1.6 mg/kg per day for 3 days [MPD group]) or antibiotics plus placebo (placebo group) every 6 hours for 3 days. Patients were reassessed by using DMSA 6 months after treatment. The primary outcome was the development of renal scars.

RESULTS

A total of 84 patients were enrolled: 19 in the MPD group and 65 in the placebo group. Patient characteristics were similar between the 2 groups, including the acute inflammatory parameters and the initial DMSA result. Renal scarring was found in 33.3% of children treated with MPD and in 60.0% of those who received placebo (P < .05). The median cortical defect volumes on follow-up DMSA were 0.0 mL (range: 0-4.5 mL) and 1.5 mL (range: 0-14.8 mL) for the MPD and placebo groups, respectively (P < .01). Patients in the MPD group experienced faster defervescence after treatment than the placebo group.

CONCLUSIONS

Adjunctive oral MPD therapy reduced the occurrence and/or severity of renal scarring after acute pyelonephritis in these hospitalized children who had a high risk of renal scar formation.

Primary hypertension and special aspects of hypertension in older children and adolescents

The prevalence of hypertension has increased at an accelerated rate in older children and adolescents. This has raised great concern about premature development of cardiovascular disease, which has major long-term health and financial implications. While obesity and sedentary habits largely explain this phenomenon, there are other social and cultural influences that may unmask genetic susceptibility to hypertension in the pediatric population. While it is essential to exclude numerous causes of secondary hypertension in every child, these disorders are not discussed in this review. Rather, the aim of this review is to familiarize pediatricians with casual and ambulatory blood pressure measurement, epidemiology, pathophysiology, and management of several common conditions that play a role in the development of hypertension in children and adolescents. Besides primary hypertension and obesity-related hypertension, emphasis is given to epidemiology, measurement of blood pressure, including ambulatory blood pressure monitoring, hypertension associated with drug use, teenage pregnancy, and video and computer games. Lastly, because pediatricians are increasingly confronted with special issues concerning the management of the hypertensive athlete, this topic is also addressed.

The definition of daytime and nighttime influences the interpretation of ABPM in children

To test if an arbitrary definition of day and night periods that differs to patient-reported awake and sleep periods leads to inaccuracies in interpretation of ambulatory blood pressure monitoring (ABPM). A single-center, retrospective review was performed comparing three different methods to classify day and night periods following a single 24-h ABPM: method A: Patient's record during monitoring; method B: 7:00 am to 11:00 pm day and 11:00 pm to 7:00 am night; method C: 8:00 am to 8:00 pm day and midnight to 6:00 am night. We included 149 studies in 149 children with a mean ± SD age of 13.0 ± 3.4 years. Reported sleep duration was 9.2  ± 1.3 h. Significant differences resulted between three methods for the means of several ambulatory BP parameters including indexed BP values during day, BP load, and nocturnal dipping status. During monitoring [median (range)], 7.5% (0.0-27.5%) readings were misclassified using method B and 0.0% (0.0-20.0%) using method C (p < 0.0001). This misclassification resulted in change of hypertension status for 11.4% (17/149) patients using method B and 9.4% (14/149) patients using method C (p = 0.70). Misclassification of measurements during ABPM can introduce significant errors in its interpretation. The clinical impact of these findings needs further evaluation in larger prospective studies.

Altered cardiovascular rhythmicity in children with white coat and ambulatory hypertension

Adults with ambulatory hypertension or white coat hypertension (WCH) display abnormal cardiovascular rhythms. We studied cardiovascular rhythms by Fourier analysis of 24-h ambulatory blood pressure (BP) measurement profiles in 129 hypertensive children, 54 children with WCH, and 146 age-, height-, and gender-matched healthy subjects. The day/night mean arterial pressure ratio was lower in hypertensive and patients with WCH compared with controls (1.13 versus 1.16 versus 1.21, respectively; p < 0.0001). Eighty-five percent of controls were dippers compared with 74% of WCH (n.s.) and 64% of patients with ambulatory hypertension (p < 0.0001). The prevalence of 24-h rhythms was similar among the groups, but prevalence of 12-h BP rhythms was increased in hypertensive (67%) and WCH (72%) compared with controls (51%, p < 0.0001). The amplitudes of the 24-, 8-, and 6-h BP rhythms were reduced in hypertensive and WCH compared with controls (p < 0.05). Hypertensive and patients with WCH displayed delayed 24-, 12-, 8-, 6-h acrophases in comparison with controls (p < 0.05). In conclusion, hypertensive children exhibit abnormal cardiovascular rhythmicity compared with controls, especially a higher prevalence of nondipping compared with normotensive children. Abnormalities in patients with WCH are intermediate between healthy children and patients with ambulatory hypertension.

Imaging studies for first urinary tract infection in infants less than 6 months old: can they be more selective?

This retrospective study aimed to evaluate the applicability of the selective approach of imaging infants < 6 months old with urinary tract infection (UTI) according to the UTI guidelines of the National Institute for Health and Clinical Excellence (NICE) 2007. Infants < 6 months old with their first UTI from January 2001 to December 2006 having undergone an ultrasound examination of the urinary tract, a micturating cystourethrogram, and a late di-mercaptosuccinic acid (DMSA) scan, were included. Their condition was evaluated against a set of risk features according to the UTI guidelines. Those having any one of these were classified as atypical and those having none as typical. There were 134 infants reviewed, with a typical (98 infants) to atypical (36 infants) ratio of 2.7 to 1. Girls were found to be relatively more represented in the atypical group [male (M):female (F) = 1.3:1] than in the typical group (M:F = 4.4:1) (P < 0.004). There were significantly more infants with abnormal micturating voiding cystourethrograms (MCUGs) (P = 0.007), more refluxing ureters (P < 0.001) and more significant vesico-ureteral reflux (VUR) (>/= grade III) (P = 0.013) in the atypical group than in the typical group; while there was no significant difference in ultrasound (US) and DMSA scan findings between the two groups. In the atypical group there was no difference in imaging studies (and, thus, the results) between the conventional practice and the NICE UTI recommendation. In the typical group, if the recommendations of the guidelines had been followed (i.e. only those with abnormal US would have been further investigated), 25 refluxing ureters and 22 scarred kidneys would have been left undiagnosed. In conclusion, application of the suggested selective imaging approach would leave a significant number of VUR and renal scars undiagnosed, and it may not be an optimal practice for infants less than 6 months old with their first UTI. The best approach remains to be clarified.

Comparison of ambulatory blood pressure reference standards in children evaluated for hypertension

OBJECTIVE

The purpose of this study was to systematically compare methods for standardization of blood pressure levels obtained by ambulatory blood pressure monitoring (ABPM) in a group of 111 children studied at our institution.

METHODS

Blood pressure indices, blood pressure loads and standard deviation scores were calculated using the original ABPM and the modified reference standards. Bland-Altman plots and kappa statistics for the level of agreement were generated.

RESULTS

Overall, the agreement between the two methods was excellent; however, approximately 5% of children were classified differently by one as compared with the other method.

CONCLUSION

Depending on which version of the German Working Group's reference standards is used for interpretation of ABPM data, the classification of the individual as having hypertension or normal blood pressure may vary.

Blood pressure load, proteinuria and renal function in pre-hypertensive children

It is as yet unclear whether blood pressure load (BPL) can affect renal function in pre-hypertensive children. We have studied 250 children, with a mean age of 9.12 +/- 3.28 years, with the aim of assessing if pre-hypertension in children can indeed affect renal function. The study cohort consisted of 146 children with pre-hypertension (group P) and a control group of 104 children with normal blood pressure (group C). All children were tested for orthostatic proteinuria, an exclusion criterion, glomerular filtration rate (GFR), and proteinuria, and ambulatory blood pressure monitoring was performed. Based on the BPL, group P was further subdivided into group P1 (BPL <or= 40%, low BPL) and group P2 (BPL > 40%, high BPL). We found that GFR was reduced in pre-hypertensive children (90.74 +/- 48.69 vs. 110.32 +/- 20.30 ml/min per 1.73 m(2), p < 0.0001) and that proteinuria was increased (145.36 +/- 110.91 vs. 66.84 +/- 42.94 mg/m(2) per 24 h; p < 0.0001). However, mean values were still within normal limits. A comparison of the group with high BPL and that with low BPL revealed that the former had relatively reduced GFR (79.15 +/- 42.04 vs. 96.78 +/- 51.20 ml/min per 1.73 m(2); p < 0.006) and increased proteinuria (198.29 +/- 142.17 vs. 118.31 +/- 80.07 mg/m(2) per 24 h; p < 0.036). In comparison to the reference values of the normal population, the GFR was reduced and proteinuria was increased in the group with high BPL. Based on our results, pre-hypertension in children with high BPL seems to be associated with reduced GFR and increased proteinuria. A reasonable doubt remains that the patients with higher proteinuria and larger reduction of GFR may harbor an as yet unknown subclinical renal condition responsible for the onset of pre-hypertension. Therefore, children with even mildly elevated BP are at risk of developing renal damage and should change their lifestyle to prevent further increases in BP.

Dimercaptosuccinic acid (DMSA) renal scan in the evaluation of hypertension in children

Renal scarring is known to be associated with hypertension. The primary objective of this study was to investigate the prevalence of renal scarring in children referred to our clinic with hypertension. The secondary objective was to compare renal ultrasound (US) examination with dimercaptosuccinic acid (DMSA) renal scan in diagnosing renal scars in these patients. The study included 159 patients who underwent DMSA renal scan as well as renal US for the evaluation of hypertension of unknown etiology. Thirty-three (21%) patients were found to have renal scars; their demographic details, including mean age and gender distribution, were not significantly different from those without renal scars. In comparison with the DMSA renal scan, sensitivity and specificity of renal US in diagnosing renal scars were 36% and 94%, respectively. In our study, in which the prevalence of scarring was 21%, this gave positive predictive and negative predictive values of 63% and 85%, respectively. In conclusion, our study indicates that renal scarring is present in 21% of otherwise healthy children who are evaluated for newly diagnosed hypertension, and renal US is not a sensitive imaging modality to rule out renal scarring.

Ambulatory blood pressure and increased left ventricular mass in children at risk for hypertension

OBJECTIVE

To relate ambulatory blood pressure (ABP) to cardiac target organ measurement in children at risk for primary hypertension (HTN).

STUDY DESIGN

Left ventricular mass index (LVMI) and ABP were measured concomitantly in children (6 to 18 years) at risk for hypertension using a cross-sectional study design.

RESULTS

LVMI showed a significant positive correlation with 24-hour systolic blood pressure (SBP) load, SBP index (SBPI), and standard deviation score (SDS). When subjects were stratified by LVMI percentile, there were significant differences in SBP load, 24-hour SBPI, and 24-hour SSDS. The odds ratio (OR) of having elevated LVMI increased by 54% for each incremental increase of SDS in 24-hour SSDS after controlling for race and BMI (OR = 1.54, unit = 1 SDS, CI = 1.1, 2.15, P = .011) and increased by 88% for each increase of 0.1 in BPI (OR = 1.88, CI = 1.03, 3.45, P = .04). Subjects with stage 3 HTN had significantly greater mean LVMI compared with normal subjects (P = .002 by ANOVA; LMVI, 31.6 +/- 7.9 versus 39.5 +/- 10.4).

CONCLUSIONS

As systolic ABP variables increase, there is greater likelihood for increased LVMI. Staging based on ABPM allows assessment of cardiovascular risk in children with primary hypertension.

Imaging in urinary tract infections: current strategies and new trends

The aim of imaging in a child with urinary tract infection (UTI) is to detect abnormalities that require appropriate treatment or findings that can be acted on to prevent development of complications (hypertension, chronic renal failure or pregnancy-related complications). Imaging protocols in pediatric urinary tract infections are evolving. From strategies based on extensive investigations in all children younger than 7 years of age, we are slowly moving to imaging strategies focused on children at risk of developing renal damage and possibly long-term complications. The article provides an overview on urinary tract infections, their complications and the use of imaging in their management. The different imaging strategies in children with UTIs (including the recommendation of excluding from imaging certain groups of patients) still needs full evaluation. It is interesting to note, however, a slow move from wide use of cystography in all children with UTI, which has been standard practice for many years but was probably not based on solid scientific evidence, toward a more focused use of cystograms in specific groups of children.

Imaging in childhood urinary tract infections: time to reduce investigations

The correct protocol for investigating urinary tract infections (UTI) is unknown but remains a hotly debated topic. The main objective in investigating children with UTI is to prevent the long-term complications of developing hypertension, chronic kidney disease (CKD) and/or pregnancy complications. However, the prognosis for childhood UTI remains good, with low long-term risks, from epidemiological studies, of developing these sequelae. Although childhood UTI is common, the occurrence of CKD and the likelihood that acute pyelonephritis will cause renal damage progressing to CKD are rare. We studied the current literature on investigations of childhood UTI and propose a protocol for carrying out selected investigations in high-risk children. By identifying this group of children with increased risk of having an abnormal urinary tract that warrant investigation, we recommend that targeting investigations to specific children (as opposed to protocol-based investigations of all children with UTI), will be clinically safe and effective and will avoid the unnecessary distress and cost of invasive investigations.

Long-term evolution of renal damage associated with unilateral vesicoureteral reflux

PURPOSE

We determined the long-term evolution of renal damage associated with vesicoureteral reflux.

MATERIALS AND METHODS

We retrospectively selected 74 consecutive children with unilateral primary vesicoureteral reflux, ipsilateral renal differential uptake less than 45% at dimercapto-succinic acid scintigraphy performed 4 to 6 months after urinary tract infection (60 patients) or shortly after diagnosis of vesicoureteral reflux investigated for prenatal hydronephrosis (14), and normal ultrasound and scintigraphic imaging of the contralateral nonrefluxing kidney. Average patient age at diagnosis was 3 years. The outcome was assessed via dimercapto-succinic acid scan at 5 to 24 years (mean 8.9).

RESULTS

In 65 patients (88%) variations of less than 5% in differential uptake were recorded. Three patients (4%) showed an increase of greater than 5% in differential uptake of the refluxing kidney. Six patients (8%) demonstrated a decrease of greater than 5%, of whom 3 had 1 and 3 had no febrile urinary tract infection during followup. A total of 18 patients had a differential uptake of 35% to 45% at the first visit, of whom 3 exhibited a decrease of 5.2% to 27% in differential uptake and had no history of febrile urinary tract infection.

CONCLUSIONS

In most cases differential uptake of the unilaterally refluxing affected kidney remains stable from early childhood to puberty despite the increase in body mass, which necessitates increasing renal work. In some patients a significant decrease in differential uptake may be observed even in the absence of recurrent febrile urinary tract infections. A mild decrease in differential uptake (35% to 45%) at diagnosis does not exclude the possibility of a subsequent significant decrease, even in the absence of febrile urinary tract infection.

Ambulatory blood pressure monitoring: what a pediatrician should know

PURPOSE OF REVIEW

Ambulatory blood pressure monitoring is a useful tool for the evaluation and management of hypertension in children and adolescents. This review provides a basic overview of ambulatory blood pressure monitoring and summarizes the most recent available knowledge regarding its use in the pediatric population.

RECENT FINDINGS

Evaluation and validation of ambulatory blood pressure monitoring equipment in children remains limited, although advances in the interpretation of results for this age group have been reported specifically in the area of circadian (24 h) and ultradian (<24 h) variability. Blood pressure is a dynamic phenomenon that varies not only with time but also with changing patient and environmental circumstances. Growing evidence regarding conditions identified when this variability is considered, specifically white coat and masked hypertension, suggests that office blood pressure measurement may not be a sufficient screening test for hypertension-related target-organ damage.

SUMMARY

Information regarding ambulatory blood pressure monitoring use in children is increasing, although due to its limitations and expense, it remains a tool primarily utilized by the pediatric sub-specialist.

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. "Accurate" refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.

The choice of threshold limits for pediatric ambulatory blood pressure monitoring influences clinical decisions

OBJECTIVES

Hypertension in children may be defined by blood pressure elevated above the 95th percentile according to sex and age. Population data for ambulatory blood pressure provide different age-related and sex-related threshold limits to office-derived data. We sought to determine whether, when using ambulatory blood pressure monitoring in a clinical setting, changing 95th percentile threshold limit sets from office-derived to ambulatory blood pressure-derived would lead to different diagnostic decisions.

METHODS

Three nephrologists who were blinded as to patient identity and limit setting method reported on 42 ambulatory blood pressure records from a mixed group of patients aged 5-18 years by using both office-derived threshold limits for the 95th centile of blood pressure and ambulatory blood pressure-derived limits. Decisions regarding the presence or absence of hypertension were compared for each patient according to the limit set.

RESULTS

Thirty-five (83%) patients were considered to be hypertensive when office-derived threshold limits were used and 20% (P=0.005) fewer records were reported as showing hypertension when ambulatory blood pressure-derived threshold limits were used. When ambulatory blood pressure limits were applied, there were fewer records with an awake systolic blood pressure load >50% (P=0.004) and the average awake systolic blood pressure load was significantly lower (P<0.001).

CONCLUSION

Ambulatory blood pressure normative data tend to provide higher blood pressure limits for age and sex. Consequently, when ambulatory blood pressure data are used to set threshold limits, clinical decisions based on ambulatory blood pressure may be different than when office limits are used. These findings demonstrate the importance of using the most appropriate limit sets to analyze ambulatory blood pressure and when interpreting ambulatory blood pressure-based research.

Permanent renal parenchymal defects after febrile UTI are closely associated with vesicoureteric reflux

The finding of scintigraphic renal defects in children with febrile urinary tract infection (UTI) even in the absence of vesicoureteric reflux (VUR) has led to the conclusion that VUR is a weak predictor of renal defects in these patients. We used isotopic cystography (IC) for diagnosis of VUR in children with febrile UTI. Dimercaptosuccinic acid renal scintigraphy was performed 6 months after cure of the last UTI. Renal defects were defined by the finding of focal defects of radionuclide uptake and/or by a split renal function <43%. The study included 206 children with primary VUR and 77 without VUR. Among the subjects with and without VUR, respectively, renal defects were found in 40 and 6% (p=0.0001), focal uptake defects in 33 and 5% (p=0.0001) and split renal function <43% in 26 and 5% (p=0.0001). Permanent renal defects in children with febrile UTI are closely associated with VUR. The possibility that a child will have permanent renal defects can reasonably be ruled out on the basis of the absence of VUR by IC.

A MULTIVARIABLE ASSESSMENT OF RENAL SIZE AND GROWTH OF SCARRED KIDNEYS IN CHILDREN

PURPOSE

We applied a recently developed multivariable renal size nomogram to sonographic measurements of kidneys with known scarring to assess systematically their sizes and growth patterns compared to normal kidneys.

MATERIALS AND METHODS

We retrospectively reviewed renal sonograms of 138 kidneys (55 right and 83 left) with known scarring. The sizes of these scarred kidneys were compared to the 95% prediction limits calculated according to the multivariable renal size nomogram, adjusting for patient age, gender, race, weight and height. The growth of scarred kidneys was evaluated by fitting individual linear regression lines using serial sonographic measurements and comparing the results with normal predicted values.

RESULTS

The sizes of 89.1% of the right and 81.9% of the left scarred kidneys were within the 95% normal prediction limits. Only 17 of 138 of the scarred renal units showed smaller kidney sizes compared to the normal prediction limits. Serial sonographic measurements revealed that compared to normal predicted values, 24 of 60 left and 16 of 38 right scarred kidneys grew within +/- 1.0% annually of the boundaries of normal predicted values. Additionally, 8 left and 7 right scarred kidneys indicated a growth rate of more than 1% annually higher than the normal predicted values.

CONCLUSIONS

Multivariable analyses of renal sonographic measurements provided a dynamic picture of kidney well-being in children with renal scarring. We found that the majority of scarred kidneys were within the normal predicted limits, and a large proportion of these kidneys grew equally well compared to those with normal anatomy.

Ambulatory blood pressure monitoring: mean blood pressure and blood pressure load

Ambulatory blood pressure monitoring (ABPM) is commonly used to diagnose pediatric hypertension. Using ABPM, hypertension is usually defined as a mean BP greater than the 95th percentile for height. A BP load >30% (% of BP readings greater than the 95th percentile) is also used for the diagnosis of hypertension. The objective of this study was to determine the agreement between mean BP greater than the 95th percentile and 30% BP load for the diagnosis of hypertension using ABPM. All ABPM records (n =1,009) of patients referred for hypertension to a pediatric center were retrieved. Scans were excluded if: age was >19 and height <115 cm or >185 cm. Mean BP and BP loads were calculated for 728 scans. Agreement between mean BP greater than the 95th percentile for height and various BP loads were calculated using the kappa coefficient. The kappa coefficient of agreement between mean BP greater than the 95th percentile and 30% BP load was 0.56 and 0.57 for daytime systolic and diastolic BP, respectively. The agreement between mean night-time BP greater than the 95th percentile and 30% BP load was 0.70 and 0.66 for systolic and diastolic BP, respectively. Agreement between mean BP greater than the 95th percentile and 30% BP load is only moderate to good. Maximum agreement between mean BP greater than the 95th percentile and BP load is achieved at 50% BP load.

Reduced nocturnal blood pressure dip and sustained nighttime hypertension are specific markers of secondary hypertension

OBJECTIVE

To investigate with the use of ambulatory blood pressure (BP) monitoring whether nocturnal BP dip and nighttime BP values are different in children with untreated primary and secondary hypertension.

STUDY DESIGN

Ambulatory BP monitoring studies from 145 children with untreated hypertension were retrospectively analyzed. Forty-five children had primary hypertension and 100 children had secondary hypertension.

RESULTS

Children with secondary hypertension had lower nocturnal BP dip for systolic and diastolic BP in comparison to children with primary hypertension (8% +/- 5% vs 14% +/- 4% for systolic and 14% +/- 7% vs 22% +/- 5% for diastolic BP, P < .0001 for both). Eleven percent of children with primary hypertension were classified as nondipper (BP dip <10%) for systolic BP and no child for diastolic BP; on the contrary, in children with secondary hypertension, 65% were nondippers for systolic and 21% for diastolic BP. Nocturnal systolic and diastolic BP loads were significantly greater in children with secondary hypertension than in those with primary hypertension.

CONCLUSIONS

Reduced nocturnal BP dip and sustained nighttime BP elevation are specific markers of secondary hypertension in children with untreated hypertension. Children with blunted nocturnal BP dip or sustained nighttime hypertension should be thoroughly investigated searching for the underlying cause of hypertension.

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection

BACKGROUND

Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy.

AIMS

To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal.

METHODS

Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA.

RESULTS

VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information.

CONCLUSION

Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.

Diagnosis and management of pediatric urinary tract infections

Urinary tract infection (UTI) is among the most commonly diagnosed bacterial infections of childhood. Although frequently encountered and well researched, diagnosis and management of UTI continue to be a controversial issue with many challenges for the clinician. Prevalence studies have shown that UTI may often be missed on history and physical examination, and the decision to screen for UTI must balance the risk for missed infections with the cost and inconvenience of testing. Interpretation of rapid diagnostic tests and culture is complicated by issues of contamination, false test results, and asymptomatic colonization of the urinary tract with nonpathogenic bacteria. The appropriate treatment of UTI has been controversial and has become more complex with the emergence of resistance to commonly used antibiotics. Finally, the anatomic evaluation and long-term management of a child after a UTI have been based on limited evidence, and newer studies question some of the tenets of prior recommendations. The goal of this review is to provide an up-to-date summary of the literature with particular attention to practical questions about diagnosis and management for the clinician.

A diagnostic approach for the child with hypertension

Hypertension during childhood is not rare, with an estimated prevalence of between 1% and 2%, although it is often an underrecognized clinical entity. Elevated blood pressure may be a sign of underlying disease or it may represent early onset of essential hypertension. In recent years the measurement of blood pressure has been emphasized as an important component of the routine pediatric physical examination that enables early detection of children with hypertension. In the evaluation of the child with documented blood pressure elevation, confirmation of truly and persistently elevated blood pressure is of the utmost importance. In addition, a thorough history and a full clinical examination are essential. These are followed by appropriate investigations, which are tailored to the age of the child and to the severity of the blood pressure elevation. Investigations should not only focus on a search for the underlying cause, but also on establishing effects on target organs, complications or additional diseases and on assessment of the total cardiovascular risk to the individual patient. An algorithm, which is a valuable diagnostic tool for the diagnosis and management of the child with hypertension, is presented. All children with confirmed hypertension need long-term follow-up, counseling and treatment. In those cases where an underlying cause of the hypertension is detected, the established diagnosis then determines the specific therapy and management.