Peritoneal-pericardial communication in an adolescent on peritoneal dialysis.

BACKGROUND: Dialysate leakage into the pericardium is a rare but potentially life-threatening complication of peritoneal dialysis (PD). There has been one reported pediatric case of spontaneous peritoneo-pericardial fistula in a 2-year-old boy with tissue fragility due to malnutrition and two reported adult cases in PD patients with a history of previous cardiac surgery and/or pericardiocentesis. CASE-DIAGNOSIS/TREATMENT: We describe a 15-year-old girl with end-stage renal disease secondary to granulomatosis with polyangiitis, with recurrent pericardial effusions secondary to a peritoneo-pericardial fistula while on continuous cycling peritoneal dialysis (CCPD). She had previously presented with chylous pericardial effusion that required pericardiocentesis and subsequently developed recurrent pericardial effusions when she was commenced on CCPD 9 months later. Pericardial fluid chemistry revealed a sterile, serous fluid containing 15.1 mmol/L of glucose and <0.11 mmol/L of triglycerides. Peritoneal scintigraphy with Tc-99m labeled sulfur colloid injected intra-peritoneally confirmed the presence of a peritoneo-pericardial fistula. The pericardial effusions resolved upon switching the patient to hemodialysis (HD). CONCLUSIONS: Our case of recurrent pericardial effusions in a child on PD secondary to a peritoneo-pericardial fistula highlights the need for close follow-up in patients with a history of previous pericardiocentesis who are commenced on PD.

Hepcidin and risk of anemia in CKD: a cross-sectional and longitudinal analysis in the CKiD cohort.

BACKGROUND: Hepcidin, a key iron regulatory protein, is elevated in patients with chronic kidney disease (CKD). Its role in the development and progression of the anemia of CKD in children remains poorly defined. METHODS: Cross-sectional and longitudinal study in children aged 1-16 years with stage 2-4 CKD in the Chronic Kidney Disease in Children (CKiD) cohort (n = 133) with hepcidin measured at baseline and hemoglobin (HGB) measured annually at follow-up. Anemia was defined as HGB <5th percentile for age/sex OR treatment with an erythropoiesis-stimulating agent (ESA). RESULTS: Hepcidin levels correlated negatively with glomerular filtration rate (GFR; r = -0.22, p = 0.01) and positively with ferritin (r = 0.67, p < 0.001). At the lower end of the GFR spectrum at baseline (10th percentile, 27.5 mL/min/1.73 m(2)), higher hepcidin was associated with a 0.87 g/dL decrease in HGB during follow-up (95 % CI -1.69, -0.05 g/dL, p = 0.038). At higher GFR percentiles there was no significant association between baseline hepcidin and HGB during follow-up. Among 90 non-anemic subjects at baseline, 23.3 % developed incident anemia. In subjects with GFR ≤ the median, a higher hepcidin level was associated with an increased risk of incident anemia (at the 10th percentile GFR, HR 3.471, 95 % CI 1.228, 9.810, p = 0.019; at the 25th percentile GFR, HR 2.641, 95 % CI 1.213, 5.750, p = 0.014; at the 50th percentile GFR, HR 1.953, 95 % CI 1.011, 3.772, p = 0.046). Among subjects with GFR at the 75th percentile or above, incrementally higher baseline hepcidin was not associated with increased anemia risk. CONCLUSIONS: Higher hepcidin levels are associated with a decreased HGB and an increased risk of incident anemia, and this association is most significant among subjects with lower GFR.

Canadian Society of Nephrology commentary on the 2012 KDIGO Clinical Practice Guideline for Anemia in CKD.

The KDIGO (Kidney Disease: Improving Global Outcomes) 2012 clinical practice guideline for anemia management in patients with chronic kidney disease provides the structural and evidence base for the Canadian Society of Nephrology commentary on this guideline's relevancy and application to the Canadian health care system. While in general agreement, we provide commentary on 11 of the 61 KDIGO guideline statements. Specifically, we agreed that a therapeutic trial of iron is appropriate in cases in which a reduction in erythropoiesis-stimulating agent (ESA) dosage or avoidance of ESA and transfusion is desired, transferrin saturations are >30%, and ferritin concentrations are >500 µg/L. However, we concluded that there is insufficient evidence to support an upper target or threshold for ferritin and transferrin saturation levels. We agree with the initiation of ESA treatment when hemoglobin (Hb) level is 90-100 g/L; however, we specifically state that an acceptable range for Hb level is 95-115 g/L, with a target of 100-110 g/L, and add caution to individualization above this range due to concerns regarding the safety of ESAs. We agree that ESAs should be used with considerable caution in patients with active malignancy, history of stroke, or history of malignancy, and we suggest initiating ESA therapy at Hb level of 90 g/L and to aim for a Hb level in the range of 90-105 g/L. The reader is encouraged to note the level of evidence and review the entire KDIGO anemia guideline to interpret the guideline statements and commentary appropriately.

Echo-Doppler assessment of the biophysical properties of the aorta in children with chronic kidney disease.

Chronic kidney disease (CKD) is known to cause increased arterial stiffness, which is an important independent risk factor for adverse cardiovascular events. The purpose of this study was to assess the vascular properties of the aorta (AO) in a group of children with CKD using a noninvasive echocardiography (echo)-Doppler method. We studied 24 children with stages 2 through 5 CKD and 48 age-matched controls. Detailed echocardiographic assessment and echo-Doppler pulse wave velocity (PWV) was performed. Indices of arterial stiffness, including characteristic (Zc) and input (Zi) impedances, elastic pressure-strain modulus (Ep), and arterial wall stiffness index, were calculated. CKD patients underwent full nephrology assessment, and an iohexol glomerular filtration rate was performed, which allowed for accurate assignment of the CKD stage. CKD patients had greater median systolic blood pressure (114 vs. 110 mmHg; p < 0.04) and pulse pressure (51 vs. 40 mmHg; p < 0.001) compared with controls. PWV was similar between groups (358 vs. 344 cm s(-1); p = 0.759), whereas Zi (182 vs. 131 dyne s cm(-5); p < 0.001), Zc (146 vs. 138 dyne s cm(-5); p = 0.05), and Ep (280 vs. 230 mmHg; p < 0.02) were significantly greater in CKD than in controls. Although load-dependent measures of arterial stiffness were greater in non-dialysis dependent CKD patients, PWV was not increased compared with controls. This suggests that the increased arterial stiffness may not be permanent in these pediatric patients with kidney disease.

Hepcidin in anemia of chronic kidney disease: review for the pediatric nephrologist.

Anemia coincident with hyporesponsiveness to erythropoiesis-stimulating agents is an ongoing and prevalent problem in children with chronic kidney disease (CKD). The recently identified iron-regulatory protein hepcidin appears likely to play a significant role in this problem. Hepcidin up-regulation in the setting of CKD, with subsequent increased serum levels, results in impaired iron absorption from the intestine and decreased iron release from body storage sites. Ultimately, in the setting of such elevated levels, a state of functional iron deficiency may develop and lead to anemia due to iron-restricted erythropoiesis. Elevated hepcidin levels are expected in the face of decreased glomerular filtration rate and inflammation. Based on current evidence, it seems likely that hepcidin represents a potentially modifiable mediator of anemia of CKD and is thus a potential target for future anemia therapy. Currently, increased removal via intensified dialysis and-/or blockade of the inflammatory pathway appear to be two viable generic strategies for reducing hepcidin levels. Goals of directly manipulating the hepcidin pathway should offer the pediatric clinician new options for treating the complex anemia associated with CKD.

Pharmaceutical cost distribution in childhood chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with significant economic burdens to both patients and the healthcare system, but pharmaceutical cost analyses are uncommon despite drug therapy being a cornerstone of CKD management. METHODS: This observational, retrospective review of drug cost distribution at a single tertiary care pediatric nephrology program in Canada was conducted on prevalent patients with CKD aged 1 month to 20 years, between 1 January and 31 December 2009. RESULTS: The time-adjusted annual pharmaceutical cost of our cohort (n = 148) was just below US $250,000 with a cost per patient per year of $1,800. The highest costs were in the growth and nutrition category, followed by anemia, hypertension and bone metabolism. Total drug cost per patient increased as CKD stage advanced. Adherence was not demonstrated in any drug category, and the mean daily pill burden was nine (range 2-23). CONCLUSIONS: This study has shown that while the annual pharmaceutical costs on a per patient basis are similar between children and adults, the cost distribution is very different. An increase in awareness of the unique needs of the pediatric population should allow for more cost-effective financial planning in pediatric CKD clinics.

Association between common iron store markers and hemoglobin in children with chronic kidney disease.

BACKGROUND: Serum ferritin and transferrin saturation (TSAT) are used to assess iron status in children with chronic kidney disease (CKD), but their sensitivity in identifying those at risk of lower hemoglobin (HGB) values is unclear. METHODS: We assessed the association of iron status markers (ferritin, TSAT, and serum iron) with age- and gender-related HGB percentile in mild-to-moderate CKD in 304 children in the Chronic Kidney Disease in Children (CKiD) Study. Standardized HGB percentile values were examined by KDOQI-recommended ferritin (≥ 100 ng/ml) and TSAT (≥ 20 %) thresholds. Regression tree methods were used to identify iron status markers and clinical characteristics most associated with lower HGB percentiles. RESULTS: The cohort was 62 % male, 23 % African American, and 12 % Hispanic, median age 12 years, and median HGB 12.9 g/dl. 34 % had low TSAT and 93 % low ferritin as defined by KDOQI. Distribution of HGB percentile values was lower in those with ferritin ≥ 100 ng/ml, while TSAT ≥ 20 % was associated with only modest increase in HGB percentile. In regression tree analysis, lower glomerular filtration rate (GFR), serum iron <50 µg/dl and ferritin ≥ 100 ng/ml were most strongly associated with lower HGB percentile. CONCLUSIONS: The level of GFR was significantly associated with HGB. Higher serum ferritin was associated with lower HGB in this cohort. Low serum iron in the context of normal/increased ferritin and low HGB may be a useful indicator of iron-restricted erythropoiesis.

Low birth weight and nephron mass and their role in the progression of chronic kidney disease: a case report on identical twins with Alport disease.

We report the outcomes of 47-year-old monozygotic twins with Alport syndrome, who share the same maternal and genetic factors; however, in adulthood have discordant trajectories in the decline of their renal function. The twin with the more rapid progression to renal failure was born with low birth weight (LBW), suggesting congenital nephron deficiency and increased susceptibility to progressive renal disease, despite having the same genetically inherited kidney condition. This 'natural experiment' adds further credence to the hypothesis that LBW contributes to the susceptibility to chronic kidney disease. We suggest further studies and surveillance for this high-risk group of infants in order to gain additional insights into the impact of perinatal factors such as LBW.

Renal function in pediatric cystic fibrosis patients in the first decade of life.

With increasing life expectancy and the need for lung transplantation in the cystic fibrosis (CF) population, there are increasing reports of chronic kidney disease (CKD). However, values for baseline or longitudinal glomerular filtration rate (GFR) as measured by exogenous clearance markers are lacking in this population. Retrospective cross-sectional study in 2 to 18-year-olds cared for at a single CF center who had a GFR measured by plasma disappearance of Technetium-99 m diethylenetriaminepentaacetic acid (mGFR). The primary outcome was evidence of renal dysfunction as defined by CKD stage II or below (mGFR <90 ml/min/1.73 m(2), persistent abnormalities in urinary sediment, abnormal renal imaging). Of 63 patients evaluated, four had apparent renal dysfunction, one demonstrated decreased mGFR, and three others had persistent microscopic hematuria. The mean mGFR was substantially higher (140 ± 24 ml/min/1.73 m(2)) than expected or previously reported for healthy children. We did not demonstrate the presence of significant renal impairment after limited aminoglycoside exposure in the first decade following diagnosis with CF. However, we did document the presence of glomerular hyperfiltration in a significant proportion of our CF patients.

An outbreak of diarrhea-associated childhood hemolytic uremic syndrome: the Walkerton epidemic.

In Canada, the majority of cases of childhood hemolytic uremic syndrome (HUS) are associated with a diarrheal illness (D+) due to verotoxin-producing Escherichia coli (VTEC). Although the ingestion of undercooked beef is an important cause, we report on the largest outbreak of E. coli illness due to a contaminated supply of municipal water. We describe the clinical features and short-term outcomes of 22 children who simultaneously developed D+HUS.

Simulating inadequate dialysis and its correction using an individualized patient-derived nomogram.

Optimization of the peritoneal dialysis prescription is dependent on proper characterization of the peritoneal membrane, as obtained by the peritoneal equilibration test (PET) or similar procedure. For any individual, certain predictions can be made to allow for decisions as to number of cycles, bag strength, and other options in order to maximize both small-solute clearance and ultrafiltration. In this paper, designed to address questions around correcting nonadherence to a prescribed peritoneal dialysis (PD) prescription, Lee et al. remind us that by using modeling programs, a series of theoretical prescriptions can be generated for each patient based on changes in cycle number or bag strength. From a selection of these prescriptions and using the current cycler technology that allows for downloading recent patient run data, and uploading new prescriptions, they demonstrate that one can correct for (scripted) nonadherent dialysis in relation to small-solute clearance. Currently, PD programs should be capable of making use of concepts from this study, as well as the ability to provide prescriptive changes via multiple preprogrammed memory cards or over modem/Internet, to provide patients with individually modeled and optimized options to correct certain forms of inadequate dialysis, for example, missed cycles or hours due to power failures.

Standard-dose versus high-dose acyclovir in children treated empirically for encephalitis: a retrospective cohort study of its use and safety.

BACKGROUND: Intravenous acyclovir is the treatment of choice for herpes simplex virus encephalitis. In 2006, the American Academy of Pediatrics updated its dosing recommendations for children aged 3 months to 12 years to receive high-dose acyclovir (60 mg/kg/day). The association between acyclovir dose and toxicity is unclear. OBJECTIVE: The purpose of our study was to review our institution's experience with standard- and high-dose acyclovir for the empiric treatment of encephalitis. STUDY DESIGN, SETTING AND PATIENTS: This retrospective cohort study included patients aged 1 month to 18 years who received acyclovir as empiric treatment for encephalitis between 2005 and 2009 at a tertiary care children's hospital. We excluded patients with baseline renal impairment and those without serum creatinine measurements prior to and during treatment. MAIN OUTCOME MEASURE: The main outcome measure of this study was to compare the occurrence of renal injury or failure between children who received the standard- versus high-dose regimen. RESULTS: Sixty-one patients were included (n = 32 standard-dose; n = 29 high-dose). There was no statistical difference in change in serum creatinine from baseline between children who received standard- versus high-dose acyclovir (0 vs. 5.1 %; p = 0.79). One child in the standard-dose group and three children in the high-dose group developed renal injury or failure during treatment (3.1 vs. 10.3 %; p = 0.34). Children with renal injury or failure were older, had a longer length of stay, and longer duration of therapy than children without. CONCLUSIONS: The incidence of renal injury or failure was similar between children who received standard-dose and high-dose acyclovir.

Carotid intima-media thickness in children with CKD: results from the CKiD study.

BACKGROUND AND OBJECTIVES: In adults, increased carotid intima-media thickness (cIMT) as assessed by ultrasonography is a valid predictor of cardiovascular events. Children with CKD are known to be at increased cardiovascular risk. This study sought to identify cardiovascular risk factors associated with increased cIMT in children with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a cross-sectional analysis of cIMT obtained after 12 months of follow-up of 101 children aged 2-18 years with mild to moderate CKD (median GFR 42.9 ml/min per 1.73 m(2)) in the Chronic Kidney Disease in Children cohort study enrolled between April 2005 and September 2009 and 97 healthy pediatric controls between January 2003 and December 2008. An average of six standardized B-mode ultrasound measurements constituted the overall cIMT measurement. RESULTS: The median cIMT was 0.43 mm (interquartile range, 0.38-0.48) compared with 0.41 mm in healthy controls (P=0.03 for difference). After multivariable adjustment, the median cIMT was 0.02 mm (95% confidence interval [CI], 0.01-0.05) larger than that of the healthy controls. In a multivariable linear regression analysis, dyslipidemia and hypertension were associated with 0.05 mm (95% CI, 0.01-0.08) and 0.04 mm (95% CI, 0.003-0.08) greater mean cIMT, respectively. Body mass index, CKD etiology, GFR, birth weight, pubertal status, calcium, phosphorus, sex, and race were not associated with cIMT. CONCLUSIONS: cIMT is significantly elevated among children with CKD, as is the prevalence of other cardiovascular risk factors. Of these risk factors, hypertension and dyslipidemia are significantly associated with increased cIMT.

Prevalence and correlates of multiple cardiovascular risk factors in children with chronic kidney disease.

BACKGROUND AND OBJECTIVES: Although prevalence of traditional cardiovascular risk factors (CVRF) has been described in children with CKD, the frequency with which these CVRF occur concomitantly and the clinical characteristics associated with multiple CVRF are unknown. This study determined the prevalence and characteristics of multiple CVRF in children in the Chronic Kidney Disease in Children study. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using cross-sectional data from first follow-up visits, we determined the prevalence of four CVRF: hypertension (casual BP >95(th) percentile or self-reported hypertension with concurrent use of anti-hypertensive medication), dyslipidemia (triglycerides >130 mg/dl, HDL <40 mg/dl, non-HDL >160 mg/dl, or use of lipid-lowering medication), obesity (BMI >95(th) percentile), and abnormal glucose metabolism (fasting glucose >110 mg/dl, insulin >20 µIU/ml, or HOMA-IR >2.20, >3.61, or >3.64 for those at Tanner stage 1, 2 to 3, or 4 to 5, respectively) in 250 children (median age 12.2 years, 74% Caucasian, median iohexol-based GFR 45.2 ml/min per 1.73 m(2)). RESULTS: Forty-six percent had hypertension, 44% had dyslipidemia, 15% were obese, and 21% had abnormal glucose metabolism. Thirty-nine percent, 22%, and 13% had one, two, and three or more CVRF, respectively. In multivariate ordinal logistic regression analysis, glomerular disease and nephrotic-range proteinuria were associated with 1.96 (95% confidence interval, 1.04 to 3.72) and 2.04 (95% confidence interval, 0.94 to 4.43) higher odds of having more CVRF, respectively. CONCLUSIONS: We found high prevalence of multiple CVRF in children with mild to moderate CKD. Children with glomerular disease may be at higher risk for future cardiovascular events.