Hypertension masquerading as Pediatric Cardiomyopathy: an exercise in cognitive biases.

Heuristics and cognitive biases constantly influence clinical decision-making and often facilitate judgements under uncertainty. They can frequently, however, lead to diagnostic errors and adverse outcomes, particularly when considering rare disease processes that have common, masquerading presentations. Herein, we present two such cases of newborn infants with hypertensive renal disorders that were initially thought to have cardiomyopathy.

Dietary intake of sodium by children: Why it matters.

Dietary sodium is required in very small amounts to support circulating blood volume and blood pressure (BP). Available nutritional surveillance data suggest that most Canadian children consume sodium in excess of their dietary requirements. Approximately 80% of the sodium Canadians consume comes from processed and packaged foods. High sodium intakes in children may be an indicator of poor diet quality. Results from systematic reviews and meta-analyses have demonstrated that decreasing dietary sodium in children leads to small but clinically insignificant decreases in BP. However, population-level strategies to reduce sodium consumption, such as food product reformulation, modifying food procurement processes, and federal healthy eating policies, are important public health initiatives that can produce meaningful reductions in sodium consumption and help to prevent chronic disease in adulthood.

Value of serum cystatin C in estimating renal function in children with non-renal solid organ transplantation.

Children with non-renal solid organ transplants are surviving longer, but outcome is complicated by CKD. Accurate and frequent renal function monitoring is imperative to recognize and institute measures early to reverse, prevent, or arrest progression. This study of 59 children determined the accuracy (P30), bias, sensitivity and specificity between measured renal function by NM-GFR, and estimated GFR by three formulas: Filler (serum cystatin C), mSchwartz (serum creatinine), and CKiD (serum cystatin C, creatinine, urea, and height). Mean GFR by all formulas differed significantly from NM-GFR. Filler and mSchwartz formulas significantly increased the proportion of patients with GFR ≥ 90 mL/min/1.73 m(2) (CKD stage 1) while decreasing those with GFR 60-89 mL/min/1.73 m(2) (CKD stage 2). All formulas overestimated GFR. CKiD showed the highest P30 and lowest bias (79.7%; 6.9 mL/min/1.73 m(2) ) followed by Filler (67.7%; 19.9 mL/min/1.73 m(2) ) and Schwartz (57.6%; 26.8 mL/min/1.73 m(2) ) for all GFR values. All formulas performed best with GFR ≥ 90 mL/min/1.73 m(2) , but CKiD was the only formula to achieve 91.1% accuracy. All formulas showed high sensitivities, but low specificities at NM-GFR cutoff at 90. Thus, GFR estimated by CKiD followed by Filler formula is an adequate method to monitor renal function closely and frequently in these children.

Multifaceted support for a new medical school in Nepal devoted to rural health by a Canadian Faculty of Medicine and Dentistry.

Nepal and Alberta are literally a world apart. Yet they share a common problem of restricted access to health services in remote and rural areas. In Nepal, urban-rural disparities were one of the main issues in the recent civil war, which ended in 2006. In response to the need for improved health equity in Nepal a dedicated group of Nepali physicians began planning the Patan Academy of Health Sciences (PAHS), a new health sciences university dedicated to the education of rural health providers in the early 2000s. Beginning with a medical school the Patan Academy of Health Sciences uses international help to plan, deliver and assess its curriculum. PAHS developed an International Advisory Board (IAB) attracting international help using a model of broad, intentional recruitment and then on individuals' natural attraction to a clear mission of peace-making through health equity. Such a model provides for flexible recruitment of globally diverse experts, though it risks a lack of coordination. Until recently, the PAHS IAB has not enjoyed significant or formal support from any single international institution. However, an increasing number of the international consultants recruited by PAHS to its International Advisory Board are from the University of Alberta in Edmonton, Alberta, Canada (UAlberta). The number of UAlberta Faculty of Medicine and Dentistry members involved in the project has risen to fifteen, providing a critical mass for a coordinated effort to leverage institutional support for this partnership. This paper describes the organic growth of the UAlberta group supporting PAHS, and the ways in which it supports a sister institution in a developing nation.

Management and outcome of positive urine cultures in a neonatal intensive care unit.

OBJECTIVES: The aim of this study was to describe the management and outcome of positive urine cultures in a neonatal intensive care unit (NICU). STUDY DESIGN: A chart review was completed of infants born October 1, 2004 to December 31, 2006 and admitted to the NICU at the Royal Alexandra Hospital, Edmonton, Alberta with any growth of bacteria or fungi in urine. RESULTS: Positive urine cultures were obtained in 64 of 2936 admissions (2%) and were classified as contaminated urines (n=34), possible urinary tract infection (UTI) (n=14), definite UTI (n=10), and candidal UTI (n=6). Management was inconsistent. Two children required new assisted ventilation but no other complications occurred. CONCLUSIONS: The diagnosis of UTI in NICU is hampered by use of urine collection methods that are subject to contamination. Outcome is generally excellent, but there is a great need for guidelines on management of positive urine cultures in the NICU.

Weight and height changes and factors associated with greater weight and height gains after pediatric renal transplantation: a NAPRTCS study.

BACKGROUND.: Obesity is a significant problem among children undergoing renal transplantation. We sought to describe changes in adiposity (reflected by percent difference from the median body mass index [BMI] for height-age and sex [BMI%]) after pediatric renal transplantation and to identify risk factors for greater gains in adiposity within 12 months of transplantation and for persistence of these gains at 48 months. The changes in height-for-age were also examined. METHODS.: By using the North American Pediatric Renal Trials and Collaborative Studies registry, we performed a retrospective cohort study of children (age 2-18 years.) transplanted between 1995 and 2006, and followed up to January 2007. Multivariable linear regression was used to identify risk factors for greater gains in adiposity and height. RESULTS.: BMI was recorded at baseline in 4326 children, and collected every 6 months. Median BMI% increased by 11.37 units within 6 months; no substantial changes were seen thereafter. The pattern of change in BMI% was similar regardless of BMI% at transplant. Age 6 to 12 years at transplant, more remote transplant, female sex, black race, Hispanic ethnicity, and lower baseline BMI% were associated with significantly greater gains in adiposity both within 12 months and persisting 48 months posttransplant. Compared with daily use, no corticosteroid use at 6 and 48 months were associated with smaller increases in BMI% within the first 12 months and at 48 months, respectively. CONCLUSIONS.: The majority of children experienced early increases in BMI%, which persisted up to 4 years. Increases in BMI% were similar regardless of BMI% at baseline.

Band 3 Edmonton I, a novel mutant of the anion exchanger 1 causing spherocytosis and distal renal tubular acidosis.

dRTA (distal renal tubular acidosis) and HS (hereditary spherocytosis) are two diseases that can be caused by mutations in the gene encoding the AE1 (anion exchanger 1; Band 3). dRTA is characterized by defective urinary acidification, leading to metabolic acidosis, renal stones and failure to thrive. HS results in anaemia, which may require regular blood transfusions and splenectomy. Mutations in the gene encoding AE1 rarely cause both HS and dRTA. In the present paper, we describe a novel AE1 mutation, Band 3 Edmonton I, which causes dominant HS and recessive dRTA. The patient is a compound heterozygote with the new mutation C479W and the previously described mutation G701D. Red blood cells from the patient presented a reduced amount of AE1. Expression in a kidney cell line showed that kAE1 (kidney AE1) C479W is retained intracellularly. As kAE1 is a dimer, we performed co-expression studies and found that, in kidney cells, kAE1 C479W and G701D proteins traffic independently from each other despite their ability to form heterodimers. Therefore the patient carries one kAE1 mutant that is retained in the Golgi (G701D) and another kAE1 mutant (C479W) located in the endoplasmic reticulum of kidney cells, and is thus probably unable to reabsorb bicarbonate into the blood. We conclude that the C479W mutant is a novel trafficking mutant of AE1, which causes HS due to a decreased cell-surface AE1 protein and results in dRTA due to its intracellular retention in kidney.

Correlation between cystatin C- and renal scan-determined glomerular filtration rate in children with spina bifida.

We report on the relationships between serum cystatin C level, glomerular filtration rate (GFR) estimated from a cystatin C-based prediction equation (that of Filler and Lepage), GFR calculated by the Schwartz formula and technetium 99m-diethylene triamine penta-acetic acid ((99)Tc-DTPA)-determined GFR in 28 children with spina bifida. All children underwent measurement of height, weight, serum cystatin C level, and serum creatinine level at the time of their renal scan. The relationship between variables was assessed by Pearson correlation. Pearson correlation for the relationship between (99)Tc-DTPA GFR and GFR calculated by the cystatin C-based equation was significant and higher than that of the relationship between (99)Tc-DTPA GFR and GFR calculated by the Schwartz equation, which was not statistically significant. The correlation for Filler GFR was 0.42 (P = 0.03) and for Schwartz GFR was 0.21 (P = 0.28). Although we use renal scan determination of GFR as the best measure, and a creatinine-based formula as the most practical measure, perhaps a formula such as that published by Filler and Lepage, which is not dependent on anthropometric data, might be a more useful (and accurate) tool for establishing GFR in children with spina bifida.

A brain protein centered view of H+ buffering.

In the traditional approach to buffering of H(+) during metabolic acidosis, the sole focus is on lowering the H(+) concentration, but this overlooks several important points. First, increased binding of H(+) to proteins changes their charge, shape, and possibly function. Second, organs in which buffering of H(+) occurs is not assessed even though it would be advantageous to spare brain proteins in this process. Third, only the arterial and not the capillary PCO(2) of individual organs is considered. This article provides a "brain protein-centered" view, which leads to different conclusions concerning the way H(+) are removed physiologically.

Clinical practice guidelines for pediatric peritoneal dialysis.

Peritoneal dialysis (PD) continues to be an important modality of treatment for children with end-stage renal disease. The Canadian Association of Pediatric Nephrologists recognized the need nationally to review the literature on the delivery of PD in children to provide optimal standardized care. This resulted in the development of the Canadian Clinical Practice Guidelines for pediatric PD. Clinical practice guidelines are a useful adjunct to clinical care. The present review includes recommendations for catheter placement and types, requirement for prophylactic omentectomy, initiation and adequacy of dialysis, PD prescription, and solute clearance. It provides physicians with updated evidence-based recommendations that include consideration towards practicality with the major goal of improved and standardized patient care.

The safety and use of short-acting nifedipine in hospitalized hypertensive children.

Recent reports suggest that calcium channel blockers are harmful in the treatment of acute hypertension in adults. However, short-acting nifedipine is an effective and useful medication in pediatric hypertension and is currently utilized for hypertensive emergencies. This study will address these safety concerns in hypertensive children. Medical records (from five Canadian pediatric hospitals) of all pediatric hypertensive hospitalized children who were treated with short-acting nifedipine from January 1995 to December 1998 were retrospectively reviewed for patient demographics, dosing regimen, use of concomitant medications, co-morbid conditions, and presence/absence of minor and serious adverse events. Final data were extracted from 182 patients. Each patient had an average of 2.6 episodes of hypertension in hospital that required treatment, totaling 477 episodes. Within the 477 episodes, 1,162 doses of short-acting nifedipine were administered. The mean dose was 0.22 mg/kg (range 0.043-0.67 mg/kg, median 0.19 mg/kg) with 55.6% (260/468 episodes) receiving the drug via the sublingual route. Hypertension resolved in 85.5% (408/477) of the episodes. There were only 29 of 574 (5.1%) minor adverse events that were definitely or probably related to short-acting nifedipine administration. Two patients experienced a serious adverse event that involved of a reduction in blood pressure of more than 40%, but neither had any symptomatology from the serious adverse event and recovered spontaneously within 2 h. Short-acting nifedipine in hypertensive, hospitalized children appears to be a safe and efficacious medication with minimal side effects.

Tacrolimus therapy in pediatric patients with treatment-resistant nephrotic syndrome.

This is a retrospective analysis of 16 children started on tacrolimus with various types of treatment-resistant nephrotic syndrome. There are 13 patients with focal glomerulosclerosis, 1 minimal change disease, and 2 IgA nephropathy with nephrosis. The mean age of the children was 11.4 years (range 3.5-18.1 years) with a mean age at diagnosis of 5.6 years (range 1.6-13.3 years). All patients initially received prednisone 2 mg/kg per day. Other therapies for 15 of 16 included cyclosporine (n=15), chlorambucil (n=5), mycophenolate mofetil (n=5), levamisole (n=3), i.v. methylprednisolone (n=3), and cyclophosphamide (n=2). The major indication for the initiation of tacrolimus included treatment resistance/dependence (n=15) and intolerable side effects from other therapies (n=1). The average time from the diagnosis to initiation of tacrolimus was 5.3 years (range 0.3-13.3 years, median 6 years). The initial dosage of tacrolimus utilized was 0.1 mg/kg per day divided into two doses. The mean follow-up period was 6.5 months (range 2.5-18 months). Thirteen patients (81%) went into a complete remission within an average of 2 months (range 0.5-5.5 months), with 3 patients relapsing while on treatment. Three patients did not respond. Of these, 2 had partial remissions (13%) and 1 failed to respond. Adverse events included anemia (n=1), seizure (n=1), worsening or new-onset hypertension (n=5), and sepsis (n=1). All patients remain on tacrolimus. Tacrolimus is an effective, well-tolerated medication for treatment-resistant forms of nephrotic syndrome in children, with a complete remission rate of 81% and a partial remission rate of 13% (totaling 94%).

Renal artery stenosis and nephrotic syndrome: a rare combination in an infant.

We describe an uncommon pediatric finding of unilateral renal artery stenosis, which presented as nephrotic syndrome, hypertension, failure to thrive, and hyponatremia. The child was a previously well 8-month-old male who looked well but had mild periorbital edema with severe hypertension. After 3 days of captopril therapy, the nephrotic-range proteinuria significantly improved. However, the hypertension persisted. Renal imaging revealed a small left kidney with reduced parenchymal uptake and no significant excretion. A renal angiogram demonstrated left renal artery stenosis with increased left renal vein renin activity. The hypertension resolved within 24 h of a left nephrectomy, but non-nephrotic-range proteinuria persisted for 8 months post operatively. Pathology of the left kidney was consistent with fibromuscular dysplasia. Although a few glomeruli (1%) had changes consistent with focal segmental glomerulosclerosis, such a few abnormal glomeruli were unlikely to account for the nephrotic syndrome. Hypertension-induced changes in the unaffected right kidney probably caused the nephrotic-range proteinuria.