Measurement and Estimation of Glomerular Filtration Rate in Children.

Rapid, accurate, and precise measures of kidney function are essential for daily management of patients. While plasma and urinary clearances provide the greatest accuracy for assessing glomerular filtration rate (GFR), these are often impractical particularly for the care of children. Serum creatinine, the most commonly used endogenous marker, is simple, convenient, and practical but less accurate because of the influence of non-GFR determinants such as muscle mass, which increases with age in children. GFR estimating equations have been developed for adults and children to improve the accuracy of endogenous biomarkers, such as creatinine and cystatin C, by accounting for some of the non-GFR determinants, thus enhancing the practitioner's ability to assess GFR. In the steady state, when height is used as a surrogate for growth, there is a strong correlation between height/SCr and GFR. Current national guidelines recommend routine reporting of the estimated GFR alongside the serum creatinine value for adults using the Chronic Kidney Disease Epidemiology Collaboration creatinine-based formula and the updated Schwartz "bedside" formula (CKiD 2009) for children.

Acute Kidney Injury in Premature, Very Low-Birth-Weight Infants.

The epidemiology of neonatal acute kidney injury (AKI) is not well established, partly due to lack of a consensus definition. Preterm neonates are likely especially vulnerable to AKI. We performed a retrospective review to assess the incidence of and risk factors for AKI in very low-birth-weight (VLBW), premature infants admitted to a level 4 NICU (2006-2007). AKI was classified using a standardized definition based on changes in serum creatinine (SCr). AKI incidence varied inversely with gestational age (GA): 65% (22-25 weeks), 25% (26-28 weeks), 9% (29-32 weeks) as did severity (p < 0.001). Stage 1 AKI was most common in each cohort. Stages 2 and 3 AKI comprised approximately 60% of AKI in the 22- to 25-week cohort but 20% or less in the older cohorts. By univariate analysis, factors associated with AKI included younger GA, lower BW, lower Apgar scores, hypotension, more frequent treatment with nephrotoxic antimicrobials, longer-duration mechanical ventilation, and higher incidence of patent ductus arteriosus (PDA) requiring treatment. By multiple logistic regression analysis, only GA, hypotension, PDA, and longer duration of mechanical ventilation were independently associated with AKI. AKI was not independently associated with risk of death. Our study suggests that small increases (≥ 0.3 mg/dL) in SCr occur frequently in premature, VLBW infants, and are associated with increased morbidity but not mortality. AKI incidence and severity were highest in the youngest GA cohort. Understanding the epidemiology, risk factors, and impact of neonatal AKI is crucial as long-term premature infant survival continues to improve.

Mycoplasma hominis septic arthritis in a pediatric renal transplant recipient: case report and review of the literature.

Septic arthritis (SA) typically occurs in young children, often from Staphylococcus. With chronic immunosuppression, however, pathogens may be atypical. A 15-year-old African-American female developed Mycoplasma hominis SA in her right hip 2 months following cadaveric renal transplant (Tx). Her presentation was subtle and indolent, without fever or leukocytosis. Although reported in adult Tx recipients, M. hominis infections have not been described in pediatric recipients. Early immunosuppression (basiliximab, prednisone, tacrolimus, mycophenolate mofetil and Thymoglobulin) may have increased her susceptibility to M. hominis. Optimal therapy for M. hominis SA is not well established and relapses occur. This patient underwent joint incision and drainage, treatment for 8 weeks with doxycycline and levofloxacin guided by in vitro sensitivities, and a reduction in immunosuppression. She has been free of ongoing infection for 3 years with stable graft function (Cr 1.1 mg/dL) on moderate immunosuppression with prednisone, tacrolimus and MMF.