ABSTRACT
BACKGROUND: Urinary levels of N-acetyl-ß-D-glucosaminidase (NAG), α1-microglobulin (α1-MG), and ß2-microglobulin (ß2-MG) are measured as markers of renal tubular damage. We previously determined normal values for these urine biochemical examinations in healthy children over 3 years old. However, the values are not applicable to children younger than 2 years old, and children less than 1 year old, in particular, seem to show very high levels for all these markers. Hence, as normal values for children below 2 years old remain unclear, we determined the normal values for urinary biochemical markers in this age group. MATERIAL AND METHODS: Fresh urine samples were obtained from 293 healthy children (from newborns to 2-year-old children). All the samples were subjected to normal urinalysis. NAG, α1-MG, ß2-MG, and creatinine (Cr) levels in extracted samples were measured immediately in the central laboratory at Kanazawa Medical Center. RESULTS: The normal values for each biomarker in children below 2 years of age were determined. Additionally, urinary α1-MG levels were observed to decrease most rapidly with age, almost reaching the level at ≥ 3 years by 6 months after birth. CONCLUSION: Renal tubular function can be evaluated in children < 3 years old using the normal values. Further, the most stable and useful urinary marker from early infancy seems to be urinary α1-MG.
Subject(s)
Acetylglucosaminidase , Humans , Child , Infant , Infant, Newborn , Child, Preschool , Reference Values , Acetylglucosaminidase/urine , Biomarkers/urine , Creatinine/urineABSTRACT
Acute renal failure with severe loin pain induced by anaerobic exercise (ALPE) is a rare condition that is accompanied by wedge-shaped contrast enhancement on computed tomography (CT) without evidence of rhabdomyolysis. In two pediatric cases with ALPE, we tried to determine the relationship between findings from CT and magnetic resonance imaging (MRI). Case 1 involved a 13-year-old Japanese girl with a diagnosis of ALPE with normo-uricemia. Contrast-enhanced CT after 24 and 48 h showed a wedge-shaped excretion delay for the contrast media. A clear wedge-shaped signal hyperintensity matching the CT images was obtained by diffusion-weighted MRI. Case 2 involved a 16-year-old boy who presented with a second attack of ALPE after diagnosis of ALPE with hypouricemia 1 year earlier. Only diffusion-weighted imaging was performed. Clear wedge-shaped signal hyperintensity was apparent, similar to Case 1. MRI is safer than contrast-enhanced CT for patients with ALPE. Diffusion-weighted MRI is a very useful examination for diagnosing ALPE, providing noninvasive detection of lesions peculiar to ALPE.
