Clinical Approach to Children with Proteinuria

Proteinuria is common in pediatric and adolescent patients. Proteinuria is defined as urinary protein excretion at levels higher than 100-150 mg/m²/day in children. It can be indicative of normal or benign conditions as well as numerous types of severe underlying renal or systemic disease. The school urine screening program has been conducted in Korea since 1998. Since then, numerous patients with normal or benign proteinuria as well as early stage renal diseases have been referred to the hospital. Benign proteinuria includes orthostatic proteinuria and transient proteinuria. Most causes of proteinuria can be categorized into 3 types: 1) overflow, 2) tubular, and 3) glomerular. Although treatment should be directed at the underlying cause of the proteinuria, prompt evaluation, diagnosis, and long-term monitoring of these pediatric patients can prevent potential progression of the underlying disease process. This article provides an overview of proteinuria: its causes, methods of assessment, and algorithmic suggestions to differentiate benign from pathologic renal disease.

Clinical Approach to Children with Proteinuria

Proteinuria is common in pediatric and adolescent patients. Proteinuria is defined as urinary protein excretion at levels higher than 100-150 mg/m²/day in children. It can be indicative of normal or benign conditions as well as numerous types of severe underlying renal or systemic disease. The school urine screening program has been conducted in Korea since 1998. Since then, numerous patients with normal or benign proteinuria as well as early stage renal diseases have been referred to the hospital. Benign proteinuria includes orthostatic proteinuria and transient proteinuria. Most causes of proteinuria can be categorized into 3 types: 1) overflow, 2) tubular, and 3) glomerular. Although treatment should be directed at the underlying cause of the proteinuria, prompt evaluation, diagnosis, and long-term monitoring of these pediatric patients can prevent potential progression of the underlying disease process. This article provides an overview of proteinuria: its causes, methods of assessment, and algorithmic suggestions to differentiate benign from pathologic renal disease.

Urinary Glucose Screening for Early Detection of Asymptomatic Type 2 Diabetes in Jeonbuk Province Korean Schoolchildren

This study aimed to investigate the prevalence of glucosuria and the characteristics of diabetes in schoolchildren as detected by a school urine glucose screening program implemented from 2010 to 2013 in the Jeonbuk province area of Korea. A total of 110 children without known diabetes were analyzed. They were checked with an oral glucose tolerance test (OGTT) with other laboratory tests and their clinical data were collected. A total of 707,238 schoolchildren from a school population of 1,064,999 were screened for glucosuria. In total, over a 4-year period, 545 schoolchildren (0.077%) were positive for glucosuria on the second urine test. The prevalence of glucosuria was more common among middle and high schoolchildren than among elementary schoolchildren. Among 110 students who completed the OGTT to confirm diabetes, 40 were diagnosed with diabetes mellitus (DM); 39 children, type 2 diabetes mellitus (T2DM) and 1 child, slowly progressive insulin dependent diabetes mellitus (SPIDDM). The mean annual incidence of diabetes was 5.6 per 100,000 schoolchildren and adolescents. The subjects with diabetes diagnosed through the urine screening test showed minimal or no symptoms of diabetes. The students with diabetes were more likely to be woman and obese, and they have a higher body mass index, higher cholesterol, triglyceride, insulin, C-peptide, and fasting glucosuria values than the students with normal glucose tolerance. We identified 40 new cases of diabetes in the Korean schoolchildren with asymptomatic glucosuria on urine glucose screening. This finding shows that school urine glucose screening is a feasible and simple method for early detection of asymptomatic T2DM.

A Case of Progress to ESRD (End-Stage Renal Disease) who had Abnormal Results on Regular Screening Urinalysis and did not Follow up

In Korea, currently, elementary, middle, and high school students undergo a regular urine test. This has resulted in significantly reduced progression of chronic kidney disease to ESRD. Follow up testing for patients who have abnormal results is not being actively enforced. In Korea, They are not yet identified to reports on patients who do not follow up. Also, urine tests are commonly performed in the emergency room in pediatric patients. However, even if abnormal results are found, if it is not associated with the main symptom, medical doctors sometimes do not recommend active follow-up. We report here on a case of progress of chronic kidney disease to ESRD in a patient who did not undergo follow-up, even if she had abnormal results on systemic urinalysis.

The clinical analysis of the urinalysis screening for 362 children in five years / 中国小儿急救医学

Objective To explore the dinical significance of the continious annual urinalysis screening in finding the urinary system disease. Methods Routine urinalysis for 362 children in school was made once every year, for consecretive five year, continious five years. Results Abnormal finding cases in urinalysis:the 1th year 3 cases, the 2th year 2 cases, the 3th year 4 cases, the 4th year 4 cases, the 5th year 4 cases. Conclu-sion It has clinical significance for finding and treating timely the urinary system disease to make annuall yurine screening in children.

Follow-up of children with isolated microscopic hematuria detected in a mass school urine screening test / 소아과

PURPOSE: The isolated microscopic hematuria is the most common abnormality detected by school urinary screening, but there is no consensus about the range of investigations and long-term outcomes of isolated hematuria in children yet. This study aims to elucidate the prognosis of hematuria and the range of diagnostic studies by follow-up results. METHODS: Students with isolated hematuria who were referred to the Department of Pediatrics, Asan Medical Center from Aug. 1990 to Feb. 2004 were analysed retrospectively. Cases that presented Through significant proteinuria(>250 mg/day), other symptoms of nephritis or renal dysfunction (creatinine clearance <85 mL/min/1.73m2) were excluded. Follow-up was done every six months with checking urinalysis, serum creatinine, protein and albumin. When albuminuria was detected, 24 hour urine protein was checked. Renal biopsy was done when urine protein was over 500 mg/day. RESULTS: A total of 331 students were enrolled in this study. There were 157 males and 174 females. The mean age at presentation was 9.9+/-2.3 years(7-15 years) and mean follow-up period was 2.2+/-1.6 years(1-10 years). Seventy five(22.7 percent) patients showed the resolution of microscopic hematuria. The mean resolution period was 2.6+/-1.7 years(1-8 years). Eight(2.4 percent) patients developed significant proteinuria and renal biopsy was done in four of them. Two cases of mild IgA nephropathy and two of minimal change were detected. None of them developed hypertension. At the end of the follow-up, renal function had remained stable in all subsets of patients. CONCLUSION: The prognosis of isolated microscopic hematuria was good. This study suggests that invasive studies including renal biopsy are not necessary and a regular follow-up of urinalysis is enough for children with isolated microscopic hematuria.

The Characteristics of Membranoproliferative Glomerulonephritis I Detected from School Urine Screening

PURPOSE:In Korea, the school urine screening program is a useful tool for screening urine abnormalities. It is particularly useful in early detection of membranoproliferative glomerulonephritis(MPGN) I, which frequently progresses to chronic renal failure. In this study, we studied the medical history, laboratory findings, and histologic findings of MPGN I to gain helpful information on early detection and treatment. METHODS:The subjects were 19 children, who were diagnosed with MPGN I from kidney biopsies that were performed in ten nationwide university hospitals because of abnormal urine findings from school urine screening programs conducted from July 1999 to April 2004. We divided the patients into 2 groups, a nephrotic range proteinuria group(n=8) and a non- nephrotic proteinuria group(n=11), and retrospectively analyzed the clinical features, laboratory findings, histologic findings, treatment, and clinical course. RESULTS:The mean age at the first abnormal urinalysis was 10.6+/-2.2 years in the nephrotic proteinuria group and 9.6+/-3.2 years in the non-nephrotic proteinuria group. The mean age at the time of kidney biopsy was 11.3+/-2.3 years in the nephrotic range proteinuria group and 10.4+/-3.2 years in the non-nephrotic proteinuria group respectively. There was no significant difference in the mean age and sex between the two groups. In the nephrotic proteinuria group, 6 children had a low plasma C3 level and in the non-nephrotic proteinuria group, 8 children had a low plasma C3 level, but there was no significant difference between the 2 groups. There was no significant difference in the laboratory test results(including WBC count, RBC count, platelet count and other serologic tests) between the 2 groups except for 24 hour urine protein secretion. There was no difference between the 2 groups with regard to the acute and chronic changes in the glomerulus on light microscopic findings, IgG, IgA, Ig M, C1q, C3, C4, fibrogen deposition on immunofluoroscence findings, and mesangial deposits, subendothelial deposits, and subepithelial deposits on electron microscopic findings. The children were treated with corticosteroids, ACE(angiotensin-converting enzyme) inhibitors, dipyridamole and other immunosuppressive agents. During the course of treatment, there were no children whose clinical condition worsened. Among 19 children, 3 children went into remission (2 in the nephrotic proteinuria group, 1 in the non-nephrotic proteinuria group) and 9 children went into a partial remission(4 in the nephrotic proteinuria group, 5 in the non-nephrotic proteinuria group) on urinalysis. There was no significant difference in the treatment results between the two groups. CONCLUSION:The 73.7% of children who were incidentally diagnosed with MPGN I by the school urine screening program had reduced C3. 42.1% of the children had nephrotic range proteinuria. There were no significant differences in clinical features, laboratory test results, light microscopic, immunofluorescence microscopic, and electron microscopic findings between the nephrotic proteinuria group and the non-nephrotic proteinuria group except for the 24 hour urine protein secretion. Therefore, for early detection of MPGN I during the school urine screening program, we strongly recommend a kidney biopsy if children have abnormal urine findings such as persistent proteinuria and persistent hematuria, or if the serum C3 is reduced.