Validity of the Adrogué-Madias Formula for the Management of Acute Dysnatremias in Critically Ill Children: A Prospective Multicenter Analysis

OBJECTIVE

Current conventional formulas do not predict the expected changes in serum sodium after administration of various fluids to correct serum sodium abnormalities. The Adrogué-Madias formula is currently the preferred and widely used fluid prescription for adult patients with dysnatremias, but its therapeutic efficacy has not been validated in pediatric patients.

METHODS

In this prospective study, we used the Adrogué-Madias formula for calculating the appropriate rate of various fluids administration to correct serum sodium abnormalities in 7 critically ill children with acute dysnatremias.

RESULTS

After administration of various intravenous fluids using the Adrogué-Madias formula, the anticipated as well as the achieved sodium concentrations were almost similar.

CONCLUSIONS

This study demonstrates that the use of the Adrogué-Madias quantitative formula allows to calculate the appropriate rate of administration of various fluids. The calculated fluid administration resulted in the subsequent actual laboratory values and clinical changes.

A Systematic Review and Meta-analysis of Rituximab-Associated Infections Among Children and Adolescents With Glomerular Disease: Focus on the Risk of Infections

OBJECTIVE

This systematic review and meta-analysis aimed to explore rituximab (RTX) associated infectious complications in children with glomerular disease.

METHODS

We performed an electronic search of PubMed, International Scientific Information (ISI), Scopus, and EMBASE between January 2010 and July 2021. Infection rates and total drug-related adverse events were the outcomes. Statistical heterogeneity was evaluated by using the I2 statistic. When there was statistical evidence of heterogeneity (I2 > 50%, p > 0.1), a random-effect model was adopted. Data analysis was performed with Stata17.0 software.

RESULTS

A total of 7 studies with 668 patients (136 with lupus nephritis [LN] and 532 with nephrotic syndrome were included in the meta-analysis. The pooled risk ratio showed that the administration of RTX was significantly associated with lower risk of infectious complications in patients with LN and nephrotic syndrome (0.72 [95% CI 0.58, 0.85]) when compared with population data of patients without glomerular disease (p = 0.2). There was no significant difference between the LN and nephrotic syndrome groups in terms of total serious adverse events or the occurrence of infections. There was significant heterogeneity among the reported studies (Q = 42.39, p < 0.001, I2 = 81%).

CONCLUSION

Administration of RTX in children with glomerular disease is associated with a lower rate of infections when compared with population data of patients without LN or nephrotic syndrome. Additional high-quality randomized controlled trials with long-term follow-up are needed to identify the long-term potential complications. Trial registration PROPERO ID: CRD42021274869 (https://www.crd.york.ac/prospero/display_record.php?).

Urine anion gap can differentiate respiratory alkalosis from metabolic acidosis in the absence of blood gas results

INTRODUCTION

Low plasma bicarbonate concentration due to chronic respiratory alkalosis may be misdiagnosed as metabolic acidosis and mistreated with administration of alkali therapy, particularly when arterial blood gas is not available.

METHODS

We measured urine anion gap [urine (Na⁺  + K⁺ ) - (Cl^- )], as a surrogate of renal ammonium excretion in 15 patients presenting with hyperventilation and low serum bicarbonate concentration to distinguish chronic respiratory alkalosis (CRA) from metabolic acidosis (MA) when blood gas was unavailable.

RESULTS

Hyperventilation and low serum bicarbonate concentrations were associated with urine pH above 5.5 and positive urine anion gap in all, suggesting CRA. The diagnosis was later confirmed by obtaining capillary blood gas, which showed a decrease in PCO₂ and high normal pH values.

CONCLUSION

The use of urine anion gap can help to differentiate between chronic respiratory alkalosis and metabolic acidosis, especially when arterial blood gas is not obtained.

Revisiting the Management of Pediatric Kidney Transplants, A Multicenter Analysis

The newest Kidney Disease Improving Global Outcomes (KDIGO) guideline recommendations were investigated mainly for the care of adult kidney transplant recipients, but no guideline exists for the management of pediatric transplant recipients. This review provides update recommendations in the management of pediatric kidney transplantation. Four electronic databases, PubMed, EMBASE, Google Scholar, and Web of Science were searched systematically for the last two decades, using Mesh terms in English language. The Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach was used for grading the quality of the overall evidence and the strength of recommendations for each outcome across the studies. The overall quality of evidence categorized as high (A), moderate (B), low (C), or poor (D). The strength of a recommendation was determined as level 1 (recommended) or level 2 (suggested). The ungraded statements were determined on the basis of common sense to provide general advice. Of the 317 citations which were screened for the evidence review, 62 were included in data extraction. The included studies were randomized controlled trials, prospective cohorts and cross-sectional, descriptive, and review studies. Of the 115 statements, 56 (48.6%) were graded 1 (we recommend), 34 (29.5%) were graded 2 (we suggest), and 25 (21.7%) were ungraded statements. Altogether, only 22 (19.1%) of recommendations reached the "A" or "B" levels of quality of evidence. The pediatric kidney transplant recipients are different from adult recipients regarding the primary kidney diseases, surgical techniques, drug metabolism, adherence to medications, growth and neurocognitive development and immunization needs prior to transplantation.  DOI: 10.52547/ijkd.7179.

Electrocardiography is Unreliable to Detect Potential Lethal Hyperkalemia in Patients with Non-dialysis Chronic Kidney Disease

Hemodialysis patients with hypercalcemia are less likely to manifest the usual electrocardiographic changes associated with hyperkalemia than in those with normal renal function. This study was conducted to determine whether electrocardiography (ECG) is a reliable indicator to detect severe life-threatening hyperkalemia in non-dialysis CKD patients. The study was conducted at three referral university hospitals between July 2017 and June 2018. Severe hyperkalemia was defined as serum potassium concentration ≥ 8.0 mEq/L. Serum potassium, sodium, bicarbonate, calcium, and creatinine concentrations were measured and simultaneous 12-lead ECG was obtained. Patients with end-stage renal disease receiving renal replacement therapy were excluded. Also excluded were patients with the usual ECG abnormalities to hyperkalemia. Of the 438 patients screened, 10 (2.3%) aged 2-14 years with severe hyperkalemia and normal ECG findings were identified. Median serum potassium level was 8.6 mEq/L (range 8.2-9.0). All had regular sinus rhythm. P, QRS, ST segment, T morphology, PR and QT interval, and QRS duration were all normal. Hyperkalemia was associated with CKD, metabolic acidosis, and hypercalcemia in all cases. Therapy with intravenous 0.9% saline, sodium bicarbonate, glucose, insulin, calcium, and salbutamol corrected the hyperkalemia in 7 patients. The remaining three patients evinced arrhythmias requiring hemodialysis. Although rare, non-dialysis CKD patients with hypercalcemia may not manifest the usual electrographic abnormalities associated with hyperkalemia. Thus, a normal ECG finding in non-dialysis CKD patients should be interpreted with caution.

Long-term cardiometabolic consequences among adolescent offspring born to women with type1 diabetes

AIM

The aim of this study was to compare cardiometabolic measures between adolescents born to women with and without type1diabetes.

METHODS

In this cross-sectional study, 103 adolescents (51 males) aged 14-19 years, born to women with type1diabetes were enrolled in the study. Body mass index, blood pressure, urine microalbumin to creatinine ratio, hemoglobin A1c, serum urate, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, and estimated glomerular filtration rate (eGFR) were measured in all. The results were compared with 98 adolescents born to non-diabetic women.

RESULTS

In multiple linear regression models, adolescent offspring of women with type 1 diabetes had significantly higher blood pressure (Odds ratio [OR] 2·45; 95% Confidence interval [CI] 2.1-2.8, hypertension (OR 2.52; 95% CI 1.99-3.01), body mass index (OR 2.22; 95% CI: 1.76-2.69), elevated total cholesterol (OR 1.5; 95% CI 0.2-2.9), low-density lipoprotein cholesterol (OR·33; 95% CI 1.06-1.64), triglyceride (OR 1.34; 95% CI: 1.05-1.70), eGFR (OR 0.96 ;95% CI 0.81-1.11) and microlabuminuria (OR 1.1; 95% CI: 0.87-1.12) compared to offspring of women without diabetes.

CONCLUSION

The study demonstrates a strong correlation between maternal exposure to type1diabetes and higher risk of developing obesity, hypertension, dyslipidemia, eGFR, and microalbumiuria in the adolescent offspring.

Differentiating syndrome of inappropriate ADH, reset osmostat, cerebral/renal salt wasting using fractional urate excretion

OBJECTIVES

Clinical and laboratory data of reset osmostat (RO) and cerebral/renal salt wasting (C/RSW) mimic syndrome of inappropriate antidiuretic hormone (SIADH) and can pose diagnostic challenges because of significant overlapping between clinical and laboratory findings. Failure to correctly diagnose hyponatremia may result in increased mortality risk, longer hospital stay, and is cost-effective. We aim to illustrate clinical and laboratory similarities and difference among patients with hyponatremic disorders and discuss the diagnostic value of factional uprate excretion (FEurate) to differentiate SIADH from RO and C/RSW.

CASE PRESENTATIONS

We report the use of FEurate in the evaluation of three patients with hyponatremia and elevated urine osmolality in the absence of edema or clinical evidence of dehydration to differentiate SIADH from RO and C/RSW.

CONCLUSIONS

Measurement of FEurate may offset in part the diagnostic confusion imparted by the diagnoses of SIADH, RO, and C/RSW.

Efficacy of Probiotic Prophylaxis After The First Febrile Urinary Tract Infection in Children With Normal Urinary Tracts

BACKGROUND

Growing antibiotic resistance and debates over their efficacy for urinary tract infection (UTI) recurrence warrants studying nonantibiotic prophylaxis for preventing UTI recurrences.

METHODS

We randomly assigned 181 children, aged 4 months to 5 years, with a normal urinary tract after recovery from their first febrile UTI in a 1:1 ratio to receive a probiotic mixture of Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium bifidum, and Bifidobacterium lactis (n = 91) or placebo (n = 90) for a total of 18 months of therapy. The primary objective was to show the superiority of probiotic prophylaxis to placebo. The primary end point was composite cure (UTI-free survival) at 18 months, and the secondary end point was the median time to first UTI recurrence.

RESULTS

The probiotics were superior to placebo with respect to the primary efficacy end point. At 18 months, composite cure was observed in 96.7% (3 of 91) of the patients in the probiotic group and 83.3% (15 of 90) of those in the placebo group (P = .02). The median time to the first incidence of UTI recurrence was 3.5 months (range, 1-4 months) and 6.5 months (range, 2-14 months) in the probiotic and placebo groups, respectively (P = .04). The main microorganism that caused recurrent UTI was Escherichia coli, followed by Klebsiella pneumoniae, and these results were not significantly different between the 2 groups. We found no specific adverse events among the participants who received the probiotic mixture during the course of therapy.

CONCLUSIONS

The probiotics were more effective than placebo at reducing the risk of recurrent UTI in children with a normal urinary tract after their first episode of febrile UTI.

Validity of anthropometric indices in predicting high blood pressure risk factors in Iranian children and adolescents: CASPIAN-V study

Anthropometric indices have been used as indicators for predicting hypertension (HTN) in children and adolescents but it is not clear which anthropometric measures are a better index for identifying elevated blood pressure (EBP) risk factors in pediatric population. Body mass index (BMI), waist circumference (WC), weight-height ratio (WHR), a body shape index (ABSI) and blood pressure were measured in 14 008 children and adolescents aged 7-18 years in a national school-aged survey CASPIN V. Hypertension (HTN) was defined according to the 2017 American Academy of Pediatrics guidelines, using the 95th percentile. The predictive power of anthropometric indices for HTN risk factors was examined using receiver operating characteristic (ROC) analyses. Multivariate logistic regression analysis was used to compare areas under ROC curves (AUCs) among the four anthropometric indices. BMI, WC, WHR, and ABSI were significantly higher in adolescents than in children. EBP was more prevalent in boys (7.2%) than girls (5.5%), whereas the prevalence of HTN was higher in girls (11.3%) than boys 10.4%. Prevalence odds ratio was around 2 for BMI, WC, and WHR with AUCs scores of nearly 0.6 to predict EBP in both children and adolescents of both sexes. Thus, the ability of BMI z-score, WC, WHR or ASBI to identify Iranian children and adolescents at higher risk of EBP was week. WC, WHR or ASBI in combination with BMI did not improve predictive power to identify subjects at higher risk of EBP.

Performance of modified blood pressure-to-height ratio for diagnosis of hypertension in children: The CASPIAN-V study

This study aimed to evaluate the accuracy and performance of modified blood pressure-to-height ratio (MBPHR) for identifying high blood pressure (HBP) in a large population of children. This multicentric cross-sectional study was conducted on a nationally representative sample of 7349 Iranian students aged 7-12 years living in 30 provinces in Iran. High systolic blood pressure and diastolic blood pressure were defined according to the 2017 American Academy of Pediatrics (AAP) guidelines. The BP-to height ratio (BPHR) was calculated as BP (mmHg)/height (cm), MBPHR3 as BP (mmHg)/(height (cm) + 3 (13-age)), and MBPHR7 as BP (mmHg)/(height (cm) + 7 (13-age). The receiver-operating characteristic curve analysis was used to evaluate the performance of these three ratios for identification of HBP in children compared to the 2017 AAP guidelines as the gold standard. Mean age of participants was 12.29 ± 3.15 years and 3736 (50.8%) were girls. The prevalence of HBP was 11.9% (11.5% in boys, 12.3% in girls). The area under the curve (AUC) was higher for MSBPHR3/MDBPHR3 (0.97/0.98) than MSBPHR7/MDBPHR7 (0.96/0.97) and SBPHR/DBPHR (0.96/0.95) for identifying high Systolic and diastolic BP. The optimal cut-off points for MSBPHR3/MDBPH, MSBPHR7/MDBPHR7, and SBPHR/DBPHR were 0.76/0.50, 0.69/0.46, and 0.81/0.52 respectively. Negative predictive value was nearly perfect for three ratios (≥98%). Positive predictive value was higher for MBPHR3 (52.7%) than MBPHR7 (51.0%) and BPHR (39.8%). Overall, MBPHR3 had better performance than MBPHR7 and BPHR for identification of HBP in Iranian children and it may improve early hypertension recognition and control in primary screening.

Urinary polyomavirus: novel biomarker of congenital ureteropelvic junction obstruction

BACKGROUND

Pregnancy is associated with reactivation and transmission of latent polyomavirus to fetus. Polyomavirus is also known to cause ureteral stenosis and hydronephrosis.

OBJECTIVE

The aim of this study was to investigate whether the urinary polyomavirus could be used as a potential biomarker in newborns with ureteropelvic junction obstruction (UPJO).

STUDY DESIGN

Urinary polyomavirus virus was measured by PCR in 42 newborn infants with fetal hydronephrosis history. Random urine samples were obtained from newborns immediately after birth and from their mothers at the time of delivery. Results were compared with 25 healthy infants matched for gestational and postnatal ages. The diagnosis of UPJO was established by diuretic renal scintigraphy. UPJO was graded according to the Society for Fetal Urology (SFU) classification.

RESULTS

The urine samples of healthy infants showed no detectable polyomavirus. No statistically significant difference was found in the median urinary polyomavirus level between grade 1 (1000 copies/mL) and grade 2 (1500 copies/mL) UPJO infants. When the median urinary BKV values were compared for each grade of UPJO, patients with grade 3 and 4 had significantly higher urinary polyomavirus levels than those with grades 1 or 2 (P < 0.001). There was a strong correlation between the median polyomavirus in the urine of pregnant women and the urine of newborns with UPJO (P < 0.001).

DISCUSSION

Data suggest that routine screening of urinary polyomavirus may help to identify infants with severe obstruction in whom early surgical intervention could reduce the risk of developing progressive kidney disease. To the best of our knowledge this is the first prospective study to present the role of urinary polyomavirus in newborn infants with UPJO to distinguish between patients who would benefit from early surgical intervention.

CONCLUSION

Urinary polyomavirus is a potential biomarker of UPJO in newborns with fetal hydronephrosis.

Adjunctive acetazolamide therapy for the treatment of Bartter syndrome

PURPOSE

Bartter syndrome is a rare hereditary salt-losing tubulopathy caused by mutations of several genes in the thick ascending limb of Henle's loop, characterized by polyuria, hypokalemic metabolic alkalosis, growth retardation and normal blood pressure. Cyclooxygenase inhibitors, potassium-sparing diuretics and angiotensin-converting enzyme inhibitors are currently used to treat electrolyte derangements, but with poor response. Whether treatment with acetazolamide, a carbonic-anhydrase inhibitor, would result in better clinical outcomes is unknown.

METHODS

We randomly assigned children with Bartter syndrome in a 1:1 ratio to either receive indomethacin, enalapril, and spironolactone or indomethacin, enalapril, and spironolactone plus acetazolamide once daily in the morning for 4 weeks. After 2 days of washout, participants crossed over to receive the alternative intervention for 4 weeks. The present study examines the serum bicarbonate lowering effect of acetazolamide as an adjunctive therapy in children with Batter syndrome.

RESULTS

Of the 43 patients screened for eligibility, 22 (51%), between the ages 6 and 42 months, were randomized to intervention. Baseline characteristics were similar between the two groups. Addition of acetazolamide for a period of 4 weeks significantly reduced serum bicarbonate and increased serum potassium levels, parallel with a reduction in serum aldosterone and plasma renin concentration. The 24-h urine volume, sodium, potassium, and chloride decreased significantly.

CONCLUSION

Our data define a new physiologic and therapeutic role of acetazolamide for the management of children with Bartter syndrome.

Simplified Algorithm for Evaluation of Proteinuria in Clinical Practice: How should A Clinician Approach?

Background

Proteinuria is a common laboratory finding among children and adolescents. It can be identified as either a transient or a persistent finding and can represent a benign condition or a serious disease.

Methods

Pertinent medical literature for asymptomatic proteinuria in children and adolescents published in English was searched between January 1980 and May 2017 using PubMed, MEDLINE, EMBASE, and Google Scholar research databases. Of the 64 reviewed articles, 24 studies were eligible for inclusion.

Results

Random spot urine protein-to-creatinine (PCR) ratio is widely used to reliably detect proteinuria. The normal value for the spot PCR in children aged 2 years or older is less than 0.3. In children aged below 2 years, the PCR can be as high as 0.5. Orthostatic proteinuria is defined as urine PCR greater than 0.3 detected in a urine specimen during the daytime activity but less than 0.3 on the first morning void specimen. PCR above 3.0 signifies heavy proteinuria as seen in nephrotic syndrome. Orthostatic proteinuria is a frequent cause of proteinuria in asymptomatic children and adolescents, which require no specific therapy except for health maintenance follow-up. Pediatric nephrologist referral is indicated when the proteinuria is constant and persists over 6 months or is associated with hematuria, hypertension, or renal dysfunction.

Conclusions

We provide a simplified diagnostic algorithm for evaluation of proteinuria in primary care adolescents who appear well and in whom proteinuria is incidentally discovered during a routine examination.

The Growing Epidemic of Chronic Kidney Disease: Preventive Strategies to Delay the Risk for Progression to ESRD

Hypertension, obesity and metabolic syndromes are leading risk factors for the development of chronic kidney disease (CKD). Considering the high prevalence of hypertension and obesity in children and adolescents and it's risk of progression to cardiovascular disease, CKD should be considered a serious long-term health issue in children with metabolic syndrome. Prevention of CKD requires a professional teamwork consisting of primary care physicians, nephrologists, nutritionist, pharmacist, and social work to identify and manage children at risk of developing CKD in order to provide a highly valuable management strategies. This review focuses on the principles underlying the importance of a team approach for CKD prevention.

Effect of allopurinol on the glomerular filtration rate of children with chronic kidney disease

BACKGROUND

Hyperuricemia is a leading risk factor for the development of chronic kidney disease (CKD). We hypothesized that lowering serum uric acid (SUA) with allopurinol in hyperuricemic children with CKD may reduce the risk of CKD progression.

METHODS

A total of 70 children, aged 3-15 years, with elevated serum uric acid level (SUA) > 5.5 mg/dL and CKD stages 1-3 were prospectively randomized to receive allopurinol 5 mg/kg/day (study group, n = 38) or no treatment (control group, n = 32) for 4 months. The primary and secondary outcomes were changes in estimated glomerular filtration rate (eGFR) (> 10 mL/min/1.73m²) and the SUA (> 1.0 mg/dL) from baseline values, respectively.

RESULTS

Baseline age, gender, blood pressure (BP), body mass index (BMI), SUA, high-sensitive C-reactive protein (hsCRP), and eGFR were similar in allopurinol and control subjects. Allopurinol treatment resulted in a decrease in SUA, a decrease in systolic and diastolic BP, a decrease in hsCRP, and an increase in eGFR compared with the baseline values (p < 0.05 for all). No significant difference was observed in the control hyperuricemic subjects. In multiple regression analysis after incorporating variables (age, gender, BMI, systolic and diastolic BP, CRP, and SUA), eGFR was independently related to SUA both before and after treatments (p = 0.03 vs. p = 0.02, respectively). All patients in the study group tolerated allopurinol, and there were no adverse reactions observed by physical examination or reported by patients.

CONCLUSION

Urate-lowering therapy with allopurinol, over a 4-month period, can improve renal function in children with CKD stages 1-3.

Glomerular Hyperfiltration as Predictor of Cardiometabolic Risk Factors among Children and Adolescents: The Childhood and Adolescence Surveillance and Prevention of Adult-V Study

Background

The prevalence of glomerular hyperfiltration and chronic kidney disease is increasing worldwide in parallel with obesity hypertension epidemic. The effect of increases in glomerular filtrations (GFR) in children with metabolic syndrome has not been studied. The purpose of the present study is to investigate the relationship between GFR and cardiometabolic risk factors in a large sample of pediatric population.

Methods

In this nationwide survey, 3800 participants were selected by cluster random sampling from 30 provinces in Iran. Anthropometric measures, biochemical, and clinical parameters were measured. We also measured estimated GFR (eGFR) using the recently modified Schwartz equations and other known cardiometabolic risk factors such as elevated total cholesterol, high low-density lipoprotein cholesterol (LDL-C), and obesity.

Results

The response rate was 91.5% (n = 3843). The mean and standard deviation (SD) (Mean ± SD) of eGFR for girls, boys, and total population were 96.71 ± 19.46, 96.49 ± 21.69, and 96.59 ± 20 ml/min/1.73 m², respectively. Overall, 38.7% of the participants did not have any cardiometabolic risk factor. In multivariate models, the risk of elevated systolic blood pressure (BP) (odds ratio [OR]: 1.48; 95% confidence interval [CI]: 1.08-2.02), elevated diastolic BP (OR: 1.48; 95% CI: 1.08-2.02), elevated LDL-C (OR: 1.35; 95% CI: 1.07-1.70), and obesity (OR: 1.70; 95%CI: 1.24-2.33) were significantly higher in participants with higher eGFR level than those with the lower level but not with low level of high-density lipoprotein cholesterol (OR: 0.72; 95% CI: 0.60-0.88).

Conclusions

This study demonstrates an association between glomerular hyperfiltration and obesity-related hypertension in a large sample of the Iranian pediatric population, independently of other classical risk factors.

Prevention of Chemotherapy-Induced Nephrotoxicity in Children with Cancer

Children with cancer treated with cytotoxic drugs are frequently at risk of developing renal dysfunction. The cytotoxic drugs that are widely used for cancer treatment in children are cisplatin (CPL), ifosfamide (IFO), carboplatin, and methotrexate (MTX). Mechanisms of anticancer drug-induced renal disorders are different and include acute kidney injury (AKI), tubulointerstitial disease, vascular damage, hemolytic uremic syndrome (HUS), and intrarenal obstruction. CPL nephrotoxicity is dose-related and is often demonstrated with hypomagnesemia, hypokalemia, and impaired renal function with rising serum creatinine and blood urea nitrogen levels. CPL, mitomycin C, and gemcitabine treatment cause vascular injury and HUS. High-dose IFO, streptozocin, and azacitidine cause renal tubular dysfunction manifested by Fanconi syndrome, rickets, and osteomalacia. AKI is a common adverse effect of MTX, interferon-alpha, and nitrosourea compound treatment. These strategies to reduce the cytotoxic drug-induced nephrotoxicity should include adequate hydration, forced diuresis, and urinary alkalization. Amifostine, sodium thiosulfate, and diethyldithiocarbamate provide protection against CPL-induced renal toxicity.

Preventive Kidney Stones: Continue Medical Education

Nephrolithiasis is a common health problem across the globe with a prevalence of 15%-20%. Idiopathic hypercalciuria is the most common cause of nephrolithiasis, and calcium oxalate stones are the most common type of stones in idiopathic hypercalciuric patients. Calcium phosphate stones are frequently associated with other diseases such as renal tubular acidosis type 1, urinary tract infections, and hyperparathyroidism. Compared with flat abdominal film and renal sonography, a noncontrast helical computed tomography scan of the abdomen is the diagnostic procedure of choice for detection of small and radiolucent kidney stones with sensitivity and specificity of nearly 100%. Stones smaller than 5 mm in diameter often pass the urinary tract system and rarely require surgical interventions. The main risk factors for stone formation are low urine output, high urinary concentrations of calcium, oxalate, phosphate, and uric acid compounded by a lower excretion of magnesium and citrate. A complete metabolic workup to identify the risk factors is highly recommended in patients who have passed multiple kidney stones or those with recurrent disease. Calcium oxalate and calcium phosphate stones are treated by the use of thiazide diuretics, allopurinol, and potassium citrate. Strategies to prevent kidney stone recurrence should include the elimination of the identified risk factors and a dietary regimen low in salt and protein, rich in calcium and magnesium which is coupled with adequate fluid intake.

Passive Leg Raising: Simple and Reliable Technique to Prevent Fluid Overload in Critically ill Patients

Background:

Dynamic measures, the response to stroke volume (SV) to fluid loading, have been used successfully to guide fluid management decisions in critically ill patients. However, application of dynamic measures is often inaccurate to predict fluid responsiveness in patients with arrhythmias, ventricular dysfunction or spontaneously breathing critically ill patients. Passive leg raising (PLR) is a simple bedside maneuver that may provide an accurate alternative to guide fluid resuscitation in hypovolemic critically ill patients.

Methods:

Pertinent medical literature for fluid responsiveness in the critically ill patient published in English was searched over the past three decades, and then the search was extended as linked citations indicated.

Results:

Thirty-three studies including observational studies, randomized control trials, systemic review, and meta-analysis studies evaluating fluid responsiveness in the critically ill patient met selection criteria.

Conclusions:

PLR coupled with real-time SV monitors is considered a simple, noninvasive, and accurate method to determine fluid responsiveness in critically ill patients with high sensitivity and specificity for a 10% increase in SV. The adverse effect of albumin on the mortality of head trauma patients and chloride-rich crystalloids on mortality and kidney function needs to be considered when choosing the type of fluid for resuscitation.

Sildenafil for the Treatment of Congenital Nephrogenic Diabetes Insipidus

BACKGROUND

Congenital nephrogenic diabetes insipidus (NDI) is characterized by massive polyuria and polydipsia due to defects in the vasopressin-sensitive signaling system expression of the acuaporin-2 (AQP2) water channel of the kidney collecting duct principal cells. Current conventional treatment regimen including hydration, diuretics and nonsteroidal anti-inflammatory drugs can only partially reduce polyuria. Recent experimental studies have suggested that treatment with sildenafil, a selective phosphodiesterase inhibitor, may enhance cyclic guanosine monophosphate (cGMP)-mediated apical trafficking of AQP2 and may be effective in increasing water reabsorption in patients with congenital NDI.

PATIENT AND METHODS

A 4-year old boy with X-linked NDI resistant to conventional therapy was treated with sildenafil for 10 days after a 2-day washout period between the 2 treatment regimens. Aliquots of the 24-hour urine collections before and after treatment were analyzed for urine volume, osmolality, cGMP and AQP2 determinations. Blood samples were also obtained for sodium and osmolality measurements. The primary endpoint was 24-hour urine volume after 10 days of sildenafil and conventional treatments.

RESULTS

Compared to conventional therapy, treatment with sildenafil resulted in substantial reduction in 24-hour urine volume (1,764 vs. 950 ml) and serum sodium (148 vs. 139) mEq/l, and increased urine osmolality (104 vs. 215 mOsm/l), and AQP2 excretion (5 vs. 26 fmol/mg creatinine). The patient tolerated sildenafil well and experienced no adverse effects.

CONCLUSIONS

Sildenafil citrate should be considered an alternative agent in the treatment of X-linked NDI resistant to conventional therapy.

Drug dosage in continuous venoveno hemofiltration in critically ill children

The dosage of drugs in patients requiring continuous renal replacement therapy need to be adjusted based on a number of variables that that affect pharmacokinetics (PK) including patient weight, CRRT modality (convention, vs. diffusion), blood and/or effluent flow, hemofilter characteristics, physiochemical drug properties, volume of distribution, protein binding and half-life as well as residual renal function. There is a paucity of data on PK studies in children with acute kidney injury requiring CRRT. When possible, therapeutic drug monitoring should be utilized for those medications where serum drug concentrations can be obtained in a clinically relevant time frame. Also, a patient-centered team approach that includes an intensive care unit pharmacist is recommended to prevent medication-related errors and enhance safe and effective medication use is highly recommended. The aim of this article is to review the current guidelines for drug dosing in critically ill children who require continuous venovenous hemofiltration.

Practical considerations to drug dosing in children with acute kidney injury

Medication dosing for children with acute kidney injury (AKI) needs to be individualized based on pharmacokinetic and pharmacodynamic principles of the prescribed drugswhenever possible to optimize therapeutic outcome and to minimize toxicity. The pediatric RIFLE criteria should be prospectively utilized to identify patients at highest risk of developing AKI. Serum creatinine and urine output along with volume status should be utilized to guide drug dosing when urinary biomarkers including kidney injury molecule 1, interleukin-18, or neutrophil gelatinase-associated lipocalin are not readily available. Because of the presence of a positive fluid balance in early stages of AKI, the dosing regimen for many drugs, especially antimicrobial agents, should be initiated at a larger loading dose based on the expected volume of distribution to achieve target serum concentrations.When possible, therapeutic drug monitoring should be utilized for those medications where serum drug concentrations can be obtained in a clinically relevant time frame. For these medications, close monitoring of serum drug concentrations is highly recommended. This review addresses drug-dosing strategies in pediatric patients with AKI including the roles of therapeutic drug monitoring and newer kidney injury biomarkers.

Drug-induced renal disorders

Drug-induced nephrotoxicity are more common among infants and young children and in certain clinical situations such as underlying renal dysfunction and cardiovascular disease. Drugs can cause acute renal injury, intrarenal obstruction, interstitial nephritis, nephrotic syndrome, and acid-base and fluid electrolytes disorders. Certain drugs can cause alteration in intraglomerular hemodynamics, inflammatory changes in renal tubular cells, leading to acute kidney injury (AKI), tubulointerstitial disease and renal scarring. Drug-induced nephrotoxicity tends to occur more frequently in patients with intravascular volume depletion, diabetes, congestive heart failure, chronic kidney disease, and sepsis. Therefore, early detection of drugs adverse effects is important to prevent progression to end-stage renal disease. Preventive measures requires knowledge of mechanisms of drug-induced nephrotoxicity, understanding patients and drug-related risk factors coupled with therapeutic intervention by correcting risk factors, assessing baseline renal function before initiation of therapy, adjusting the drug dosage and avoiding use of nephrotoxic drug combinations

A treatment algorithm for children with lupus nephritis to prevent developing renal failure

Chronic kidney disease is one of the most common complication of systemic lupus erythematosus, which if untreated can lead to the end-stage renal disease (ESRD). Early diagnosis and adequate treatment of lupus nephritis (LN) is critical to prevent the chronic kidney disease incidence and to reduce the development of ESRD. The treatment of LN has changed significantly over the past decade. In patients with active proliferative LN (Classes III and IV) intravenous methylprednisolone 1 g/m2/day for 1-3 days then prednisone 0.5-1.0 mg/kg/day, tapered to <0.5 mg/kg/day after 10-12 weeks of treatment plus mycophenolate mofetile (MMF) 1.2 g/m2/day for 6 months followed by maintenance lower doses of MMF 1-2 g/day or azathioprine (AZA) 2 mg/kg/day for 3 years have proven to be efficacy and less toxic than cyclophosphamide (CYC) therapy. Patients with membranous LN (Class V) plus diffuse or local proliferative LN (Class III and Class IV) should receive either the standard 6 monthly pulses of CYC (0.5-1 g/m2/month) then every 3(rd) month or to a shorter treatment course consisting of 0.5 g/m2 IV CYC every 2 weeks for six doses (total dose 3 g) followed by maintenance therapy with daily AZA (2 mg/kg/day) or MMF (0.6 g/m2/day) for 3 years. Combination of MMF plus rituximab or MMF plus calcineurin inhibitors may be an effective co-therapy for those refractory to induction or maintenance therapies. This report introduces a new treatment algorithm to prevent the development of ESRD in children with LN.

Resistant hypertension: current status, future challenges

Resistant hypertension in adolescents is increasing in frequency and is increasingly recognized as having significant short- and long-term health consequences. It may be seen in up to 30% of all hypertensive patients cared for. Adolescents with resistant hypertension are at higher cardiovascular (CV) risk due to a long history of severe hypertension complicated by other CV risk factors such as obesity. Common causes of resistant hypertension include primary aldosteronism, sleep apnea, diabetes and chronic kidney disease. Careful blood pressure (BP) measurement and thorough evaluation of patients with sustained BP elevation should make a possible early diagnosis of resistant hypertension. Successful treatment requires identification and reversal of life-style factors contributing to treatment resistant and diagnosis and appropriate treatment of causes of hypertension. Improved pharmacologic therapies may offer the potential for preventing or at least ameliorating early CV disease. This review highlights these and other important issues in the evaluation and management of adolescents with resistant hypertension and provides practical guidance to the practitioners involved in caring for such patients.

Managing hypertension in the newborn infants

Hypertension in newborn infants, particularly those requiring intensive care, is becoming increasingly recognized, with prevalence of 0.2-3%. Recent studies have established normative tables for blood pressure (BP) in both term and pre-term infants based on the gestational age, postnatal age, gender, weight and height, identifying the neonates at increased risk for early-onset cardiovascular disease. Common causes of neonatal hypertension include thromboembolic complications secondary to umbilical artery catheterization, congenital renal structural malformation, renovascular disease, aortic coarctation, as well as acute kidney injury and certain medications. A careful diagnostic evaluation should lead to identification of the underlying cause of hypertension in most infants. Treatment options should be tailored to the severity; and underlying cause of hypertension, including intravenous and/or oral therapy. This review summarizes recent work in these areas, focusing on optimal BP measurement, definition, evaluation and management of hypertension as well as advances in drug therapy of neonatal hypertension.

Strategies to reduce pitfalls in measuring blood pressure

Errors in blood pressure (BP) measurement are common in the clinical practice. Inaccurate measurements of BP may lead to misdiagnosis and inappropriate treatment of hypertension. The preferred method of BP measurement in the clinical setting is auscultation, using the first and the fifth Korotkoff sounds. However, the use of mercury sphygmomanometer is declining. Automated oscillometric devices are an acceptable alternative method of BP measurements if the proper cuff size is used. Aneroid devices are suitable, but they require frequent calibration. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. At 24 h ambulatory monitoring is also useful for diagnosing white-coat hypertension and resistance hypertension. There is increasing evidence that lack of nocturnal BP dipping during the night may be associated with increased cardiovascular event. This report attempts to address the need for accurate BP measurements in children and adolescents by reducing human and equipment errors and providing clinicians with the accurate measurement of BP, which is essential to classify individuals, to ascertain BP-related CV risks and to guide management.

Prehypertension: a warning sign of future cardiovascular risk

Since the report from the national high blood pressure (BP) education program working group on BP in children and adolescents and the introduction of a new description called prehypertension many data have been provided on its rate of progression to hypertension, its prevalence and association with other cardiovascular (CV) risk factors and its therapy. Making a diagnosis of prehypertension in a child or adolescent identifies an individual at increased risk for early-onset CV disease who requires specific treatment. Thus, routine BP measurement is highly recommended at every health-care encounter beginning at 3 years of age. This review will present updated data on prehypertension in children and adolescents to increase awareness of health-care providers to the seriousness of this condition. Optimal BP measurement techniques as well as the evaluation and management of prehypertension will be discussed and preventive strategies to reduce the CV risk will be presented.

Management of hypertension in children with cardiovascular disease and heart failure

Although primary chronic hypertension (HTN) is increasingly common in adolescence, secondary forms of HTN are more common among children. Primary HTN is associated with being overweight and/or a positive family history of HTN. Carotid intima-media thickness, a known risk factor for atherosclerosis is frequent in both adults and children with HTN and other associated cardiovascular (CV) risk factors including obesity, dyslipidemia, diabetes and chronic kidney disease. Left ventricular (LV) hypertrophy is also a common finding in children and adolescents with newly diagnosed HTN. Children with certain medical conditions such as congenital heart disease and Kawasaki disease can develop premature atherosclerosis heart disease that may lead to coronary heart disease and heart failure. Life-style interventions are recommended for all children with HTN, with pharmacologic therapy added for symptomatic children based on the presence of co-morbidities. As an example, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blocker and/or calcium channel blockers would be best for children with CV risk factors such as diabetes or renal disease, whereas an ACE inhibitor in combination with a beta-blocker and diuretics including spironolactone are recommended for patients with heart failure and reduced LV ejection fraction. This report will summarize new developments in the management of pediatric HTN complicated with CV disease and heart failure and will address the appropriate antihypertensive therapy that could potentially reduce the future burden of adult CV disease.

Preventing kidney injury in children with neurogenic bladder dysfunction

The most common cause of neurogenic bladder dysfunction (NBD) in newborn infants is myelomeningocele. The pathophysiology almost always involves the bladder detrusor sphincter dyssynergy (DSD), which if untreated can cause severe and irreversible damage to the upper and lower urinary tracts. Early diagnosis and adequate management of NBD is critical to prevent both renal damage and bladder dysfunction and to reduce chances for the future surgeries. Initial investigation of the affected newborn infant includes a renal and bladder ultrasound, measurement of urine residual, determination of serum creatinine level, and urodynamics study. Voiding cystogram is indicated when either hydronephrosis or DSD is present. The main goal of treatment is prevention of urinary tract deterioration and achievement of continuance at an appropriate age. Clean intermittent catheterization (CIC) in combination with anticholinergic (oxybutynin) and antibiotics are instituted in those with high filling and voiding pressures, DSD and/or high grade reflux immediately after the myelomeningocele is repaired. Botulium toxin-A injection into detrusor is a safe alternative in patients with insufficient response or significant side effects to anticholinergic (oral or intravesical instillation) therapy. Surgery is an effective alternative in patients with persistent detrusor hyperactivity and/or dyssynergic detrusor sphincter despites of the CIC and maximum dosage of anticholinergic therapy. Children with NBD require care from a multidisciplinary team approach consisting of pediatricians, neurosurgeon, urologist, nephrologists, orthopedic surgeon, and other allied medical specialists.

Pediatric kidney transplantation: kids are different

The pediatric kidney transplant recipient differs from the adult recipient in many ways, including immune responsiveness, drug metabolism and clearance, perfusion of transplanted organs, and risk for posttransplant lymphoproliferative disease. Pediatric patients also have special quality of life issues such as cosmetic side effects of medications, stunted growth and sexual maturation, and separation from their peers. Congenital urological anomalies and glomerulosclerosis are the most common causes of pediatric end-stage renal disease. In the pediatric patients, consideration for preemptive transplantation should be first and arteriovenous fistula placement second. Pediatric patients should receive priority for kidneys from deceased donors to shorten the wait time for transplant. Fevers or changes in blood pressure may identify allograft dysfunction weeks before changes in creatinine occur. Thus, monitoring serum creatinine level is a poor indicator of allograft dysfunction in this setting. There is great concern about nonadherence to immunosuppressive therapy as children reach the stage of adolescence. This report highlights these and other important differences in the evaluation and management of the pediatric kidney transplant recipients compared with the adult and provides practical guidance to the practitioners involved in caring for such patients.

The growing epidemic of hypertension among children and adolescents: a challenging road ahead

Currently, it is clear that primary hypertension begins in childhood and that it contributes to the early development of chronic kidney disease (CKD). Hypertension also increases the risk of cardiovascular morbidity and mortality, and that risk rises as blood pressure levels escalate. As among adult patients, overweight and obesity rates are on the rise among children and adolescents with primary hypertension and can develop target organ damage including left ventricular hypertrophy. An elevated level of C-reactive protein (CRP) and microalbuminuria are early manifestations of cardiovascular disease and CKD in hypertensive patients. Lifestyle interventions are recommended for all children with hypertension. Pharmacologic therapy should be added for symptomatic children, those with stage 2 hypertension, and children with prehypertension and stage 1 hypertension who exhibit an insufficient response to lifestyle modifications. Although the recommendations for choice of drugs generally are similar for children and adults, dosages for children should be lower, based on weight, and adjusted very carefully. Medications that are effective and safe for children and adolescents include thiazide diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and calcium channel-blockers. Hypertension is not being detected early enough for initiation of a treatment regimen to reduce death and disability. Initiatives should be undertaken to make health care providers and the general population more aware of the seriousness of hypertension in children and adolescents. This review focuses on the principles underlying the importance of a team approach for hypertension control, especially one that incorporates increased data sharing using enhanced health information technology for early detection and intervention.

Simplified diagnostic algorithm for evaluation of neonates with prenatally detected hydronephrosis

INTRODUCTION

The management of neonates with congenital hydronephrosis (CHN) diagnosed antenatally is still controversial.

MATERIALS AND METHODS

A prospective study was performed in all newborn infants with CHN born over a 2-year period in order to identify which neonates require a full radiologic investigation including investigation with invasive tests such as voiding cystoureterography (VCUG) and diuretic-enhanced renography. Data on kidney ultrasonography, VCUG, and diuretic renography were collected. The ultrasound grading of hydronephrosis was determined according to Society of Fetal Urology criteria.

RESULTS

Sixty-one neonates (47 boys and 14 girls) with CHN were enrolled. All underwent kidney ultrasonography within 72 to 96 hours after birth. Four (7%) had no residual CHN, 34 (56%) had and 23 (38%) unilateral CHN. Of the 41 newborns exposed to diuretic renography, 18 (44%) had ureteropelvic junction obstruction (UPJO). Of the 34 infants that underwent VCUG, 8 (24%) had vesicoureteral reflux (7 bilateral grade 2 or higher, 1 unilateral grade 1 CHN SFU classification). None of the unilateral grade 1 or 2 CHN due to UPJO had vesicoureteral reflux and none with vesicoureteral reflux had UPJO. Twelve patients required surgery (7 had UPJO and 3 high-grade vesicoureteral reflux).

CONCLUSIONS

These data suggest that mild to moderate unilateral or bilateral CHN rarely coexists with severe obstruction or vesicoureteral reflux. Therefore, systemic VCUG and renography in such patients do not seem justified. Postnatal ultrasonography in combination with renography and VCUG is warranted in the routine examination of neonates presenting with severe unilateral or bilateral CHN.

Neonatal nephrotic syndrome associated with placental transmission of proinflammatory cytokines

Although there are clinical data suggesting a direct relationship between neonatal nephrotic syndrome and placental transfer of proinflammatory cytokines from mothers with HELLP syndrome, there is no direct evidence that these inflammatory cytokines are pathogenic. Here, the first human model of placental transfer of proinflammatory cytokines from a mother with HELLP syndrome to a newborn, resulting in neonatal nephrotic syndrome is described. Forty-eight hours after delivery, the neonate developed nephrotic syndrome and abnormalities in renal function which resolved completely during the 5 days following the initiation of therapy with hydrocortisone, albumin, and furosemide. The newborn's cord blood showed increased concentrations of interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha that were identical to those found in the mother's serum. Hydrocortisone therapy was discontinued after a 2-week course. Clinical and laboratory improvements were associated with a marked decline in serum cytokine levels, indicating that the proinflammatory cytokines were pathogenic. The neonate remained in remission with no recurrence of nephrotic syndrome during 12 months of follow-up. These findings demonstrate that the placental transmission of circulating cytokines causing HELLP syndrome occurred during pregnancy and may have resulted in nephrotic syndrome in the neonate.

Hypophosphatemia: an evidence-based problem-solving approach to clinical cases

Hypophosphatemia is defined as a serum phosphate level of less than 2.5 mg/dL (0.8 mmol/L). Hypophosphatemia is caused by inadequate intake, decreased intestinal absorption, excessive urinary excretion, or a shift of phosphate from the extracellular to the intracellular compartments. Renal phosphate wasting can result from genetic or acquired renal disorders. Acquired renal phosphate wasting syndromes can result from vitamin D deficiency hyperparathyroidism, oncogenic osteomalecia, and Fanconi syndrome. Genetic disorders of renal hypophosphatemic disorders generally manifest in infancy and are usually transmitted as an X-linked hypophosphatemic rickets. Symptoms of hypophosphatemia are nonspecific and most patients are asymptomatic. Severe hypophosphatemia may cause skeletal muscle weakness, myocardial dysfunction, rhabdomyolysis, and altered mental status. The diagnostic approach to hypophosphatemia should begin with the measurement of fractional phosphate excretion; if greater than 15% in the presence of hypophosphatemia, the diagnosis of renal phosphate wasting is confirmed. Renal phosphate wasting can be divided into 3 types based upon serum calcium levels: primary hyperparathyroidism (high serum calcium level), secondary hyperparathyroidism (low serum calcium level), and primary renal phosphate wasting (normal serum calcium level). Phosphate supplementations are indicated in patients who are symptomatic or who have a renal tubular defect leading to chronic phosphate wasting. Oral phosphate supplements in combination with calcitriol are the mainstay of treatment. Parenteral phosphate supplementation is generally reserved for patient with life-threatening hypophosphatemia (serum phosphate < 2.0 mg/dL). Intravenous phosphate (0.16 mmol/kg) is administered at a rate of 1 mmol/h to 3 mmol/h until a level of 2 mg/dL is reached.

Hypomagnesemia: an evidence-based approach to clinical cases

Hypomagnesemia is defined as a serum magnesium level less than 1.8 mg/dL (< 0.74 mmol/L). Hypomagnesemia may result from inadequate magnesium intake, increased gastrointestinal or renal losses, or redistribution from extracellular to intracellular space. Increased renal magnesium loss can result from genetic or acquired renal disorders. Most patients with hypomagnesemia are asymptomatic and symptoms usually do not arise until the serum magnesium concentration falls below 1.2 mg/dL. One of the most life-threatening effects of hypomagnesemia is ventricular arrhythmia. The first step to determine the likely cause of the hypomagnesemia is to measure fractional excretion of magnesium and urinary calcium-creatinine ratio. The renal response to magnesium deficiency due to increased gastrointestinal loss is to lower fractional excretion of magnesium to less than 2%. A fractional excretion above 2% in a subject with normal kidney function indicates renal magnesium wasting. Barter syndrome and loop diuretics which inhibit sodium chloride transport in the ascending loop of Henle are associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypercalciuria. Gitelman syndrome and thiazide diuretics which inhibit sodium chloride cotransporter in the distal convoluted tubule are associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypocalciuria. Familial renal magnesium wasting is associated with hypercalciuria, nephrocalcinosis, and nephrolithiasis. Asymptomatic patients should be treated with oral magnesium supplements. Parenteral magnesium should be reserved for symptomatic patients with severe magnesium deficiency (< 1.2 mg/dL). Establishment of adequate renal function is required before administering any magnesium supplementation.