A Cost-effectiveness Model Comparing Urinary Biomarkers with Diuretic Renogram in Diagnosing Ureteropelvic Junction Obstruction in Children.

Background and Aims: In this cost-effectiveness model, we compared the cost-effectiveness of commonly used urinary biomarkers with conventional diuretic renogram (DR) in diagnosing ureteropelvic junction obstruction (UPJO). We hypothesized that urinary biomarkers are as effective as DR. Methods: We used incremental cost-effectiveness ratio (ICER) as a tool for our cost-effectiveness analysis model. The cost of biomarker assay and renogram were sourced from the same center while the accuracy data of DR and urinary biomarkers from the relevant pubications. Results: As the accuracy of individual biomarker increased, the ICER also got better. As a panel of biomarker was introduced, the ICER went to the negative range suggesting cost saving as well. ICER of most urine biomarkers is currently less expensive and less effective. When a biomarker panel was applied ICER became more expensive and effective. With higher samples, test running cost is likely to go down in future and thus biomarkers are likely become less expensive and more effective. Conclusions: Individual urine biomarkers are currently less expensive and less effective compared to DR in predicting UPJO. In future, biomarker panel is likely to be more cost-effective and reduce the need for invasive renogram thus reducing the radiation exposure.

Comparing accuracy of urinary biomarkers in differentiation of ureteropelvic junction obstruction from nonobstructive dilatation in children.

Multiple urinary biomarkers have been reported in differentiation of nonobstructive dilatation (NOD) from ureteropelvic junction obstruction (UPJO). In this meta-analysis, we compared the accuracy of common urinary biomarkers applicable to UPJO. A systematic literature review of electronic databases was conducted for: (UPJO) OR (NOD) AND (urinary biomarkers) AND (children) for articles published in the last decade. PRISMA guidelines were used to exclude duplicate and erroneous articles. Meta-analysis involved risk of bias analysis, heterogeneity assessment, and comparison of sensitivity/specificity by forest plot analysis using MetaXL 5.3. Among the 264 articles analyzed, 19 articles met the inclusion criteria and reported the following: neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemotactic protein-1 (MCP1), carbohydrate antigen 19-9 (CA 19-9), kidney injury molecule (KIM1), epidermal growth factor (EGF), and interferon gamma induced protein-10 (IP10). There was substantial heterogeneity among articles. There was wide variation in applied cut-offs among studies. Overall sensitivity was highest at 87% for CA 19-9 while overall specificity was highest at 76% for NGAL. Overall accuracy was highest at 78% for CA 19-9 followed by 77% for NGAL and 75% for KIM1. In this meta-analysis, the overall accuracy was highest for CA 19-9 followed by NGAL and KIM1. The small number of studies for CA 19-9 and considerable heterogeneity for all should be considered while interpreting these findings. Based on the current meta-analysis, we support a panel of biomarkers combining NGAL, KIM, and CA 19-9 for the best diagnostic accuracy of UPJO in children.

Atypical haemolytic uraemic syndrome: a case of rare genetic mutation.

Complement-mediated kidney disease has been an evolving area in the field of nephrology. Atypical haemolytic uraemic syndrome (aHUS) is a rare thrombotic microangiopathy that affects multiple organs, particularly kidneys. The disease is characterised by a triad of haemolytic anaemia, thrombocytopenia and acute kidney injury (AKI). aHUS is most commonly caused by dysregulation of alternative complement pathway. In contrast to shiga toxin-associated haemolytic uraemic syndrome, diarrheal prodrome is usually absent in children with aHUS. We report a 2-year, 9-month-old boy who presented with acute dysentery and AKI. He had an unusual prolonged course of illness with hypocomplementaemia; hence, genetic testing was performed. He had a storming course in the hospital and succumbed to complications of the disease. Genetic study revealed digenic mutation in Complement Factor I and C3 Therefore, it is important to differentiate aHUS from other thrombotic microangiopathies to improve the outcome.

Alkaptonuria in an adolescent boy.

Alkaptonuria is a rare genetic disorder resulting in abnormality of tyrosine metabolism. It is one of the Garrod's tetrad of 'inborn errors of metabolism' proposed to have Mendelian recessive inheritance. The disorder is characterised by deposition of homogentisic acid leading to ochronosis and ochronotic osteoarthropathy; however, blackish discoloration of urine is the only childhood manifestation. Other manifestations present only after third decade. A 13-year-old boy presented to paediatric nephrology clinic with blackish discolouration of urine since infancy. Examination revealed bluish black discolouration of bilateral sclera and ear cartilage; however, he had no symptoms of ochronotic osteoarthropathy. Genetic test pointed towards alkaptonuria. Currently, he is on regular follow-up and is being treated with vitamin C to delay the progression of the disease. Early diagnosis with appropriate intervention delays the onset of complications and preserves the quality of life of the patient.

Juvenile dermatomyositis: a case of delayed recognition with unusual complication of nephrocalcinosis.

Juvenile dermatomyositis (JDM) is the most common inflammatory myopathy in children and is characterised by the presence of proximal muscle weakness, heliotrope dermatitis, Gottron's papules and occasionally auto antibodies. The disease primarily affects skin and muscles, but can also affect other organs. Renal manifestations though common in autoimmune conditions like lupus are rare in JDM. We describe a child whose presenting complaint was extensive calcinosis cutis. Subtle features of proximal muscle weakness were detected on examination. MRI of thighs and a muscle biopsy confirmed myositis. Nephrocalcinosis was found during routine ultrasound screening. We report the first case of a child presenting with rare association of dermatomyositis, calcinosis cutis and bilateral medullary nephrocalcinosis.