Therapeutic plasma exchange for the treatment of pediatric renal diseases in 2013.

Therapeutic plasma exchange is an extracorporeal treatment modality that removes systemic circulating pathologic factors or replaces absent plasma components and plays a role in many nephrologic conditions. It presents a number of technical challenges in the pediatric population but has become an increasingly common practice in pediatric nephrology over the past several decades. While prospective evidence is often lacking, our increased understanding of the molecular pathogenesis underlying many pediatric renal diseases provides sound reasoning for the use of plasma exchange in treating these conditions. This review will present the currently accepted indications for plasma exchange in children, the technical aspects of the procedure and its potential complications.

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.

Association of proteinuria with race, cause of chronic kidney disease, and glomerular filtration rate in the chronic kidney disease in children study.

BACKGROUND AND OBJECTIVES: Proteinuria is associated with chronic kidney disease (CKD), and heavy proteinuria predicts a rapid decline in kidney function. However, the epidemiologic distribution of this important biomarker study is not well described in the pediatric CKD population. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS: This cross-sectional study of North American children with CKD examined the association of proteinuria among the baseline clinical variables in the cohort. Urinary protein-to-creatinine ratios (Up/c) were used to measure level of proteinuria. RESULTS: Of the 419 subjects studied, the median GFR as measured by iohexol disappearance (iGFR) was 42 ml/min per 1.73 m(2), median duration of CKD was six yr, and glomerular diseases accounted for 22% of the CKD diagnoses. Twenty-four percent of children had normal range (Up/c <0.2), 62% had significant, and 14% had nephrotic-range proteinuria (Up/c >2.0). A decrease in iGFR was associated with an increase in Up/c. At any level of GFR, a higher Up/c was associated with a glomerular cause of CKD and non-Caucasian race. Among subjects with a glomerular cause of CKD, Up/c was lower in subjects reporting utilization of renin-angiotensin system (RAS) antagonists (median Up/c = 0.93) compared with those who did not (median Up/c = 3.78). CONCLUSIONS: Proteinuria is associated with level of iGFR, cause of CKD, and race. The longitudinal study design of Chronic Kidney Disease in Children (CKiD) cohort study and the large number of subjects being studied has created an opportunity to better define the association between proteinuria and CKD progression.

Mycobacterial peritonitis in pediatric peritoneal dialysis patients.

Peritonitis is the most common complication and the leading cause of death in pediatric peritoneal dialysis (PD) patients. According to the most recent data available from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS), approximately 25% of pediatric PD patients who die succumb to infection. There are no reported cases of Mycobacterium tuberculosis (MTB) or Mycobacterium avium-intracellulare peritonitis in the NAPRTCS registry. With an increasing incidence of MTB worldwide and the impairment of cellular immunity in chronic renal failure patients, it is not surprising that mycobacterium peritonitis can occur in PD patients. We report two pediatric PD patients with mycobacterial peritoneal infection diagnosed over an 11-year period at our institution. One patient presented with a malfunctioning Tenckhoff catheter and again 3 years later with hyponatremia and ascites. The other presented with recurrent culture-negative peritonitis. These cases illustrate the importance of more extensive evaluation of PD complications, to include evaluation for mycobacterium with special media or peritoneal biopsy, in the above clinical settings if the routine work-up is unrevealing.