Zdorovʹe Rebenka (Sep 2017)
Morphological characteristics of urine erythrocytes in children with erythrocyturia
Abstract
Background. Nephropathies with erythrocyturia make up about 1/3 of all diseases of the kidneys and the urinary system, and they have some difficulties in differential diagnostics. Quite often, erythrocyturia is the only symptom of these diseases. In connection with this, determination of its origin is an important task in forming the correct diagnosis. Erythrocyturia in most diseases of the lower urinary tract is not accompanied by proteinuria or the presence of cylinders in the urine. The presence of proteinuria (more than 0.3 g/l or 1 g protein in urine per day), along with the appearance of erythrocytic cylinder in the urine sediment, raises suspicion in favor of glomerular or tubular diseases. Glomerular erythrocytes may be detected by means of urea concentration factor (UCF) in the urinary sediment as a preliminary test for the determination of the erythrocyturia site. Erythrocytes that pass through the glomerular membrane have a changed form (dysmorphic). Determination of acanthocytes in the urine (ring-shaped erythrocytes with one or several bulges in the form of bubbles of different sizes and types) is a more precise criterion of glomerular nephropathy than the presence of dysmorphic erythrocytes. The purpose of the study was to determine the morphological characteristics of urine erythrocytes in children with erythrocyturia, to improve the quality of differential diagnosis. Materials and methods. Determination of the morphological characteristics of urinary erythrocytes using UCF in 73 patients aged 1 to 18 years, of which 45 (61.6 %) are patients with hematuric form of glomerulonephritis, 23 (31.5 %) — with hereditary nephritis, and 5 (6.8 %) — with dysmetabolic nephropathy. Detection of 50 to 80 % of dysmorphic erythrocytes in the urine sediment and finding in urine of more than 5 % of acanthocytes is a highly sensitive and specific diagnostic criterion for glomerular hematuria. Results. In children with a clinical diagnosis “glomerulonephritis, the hematuric form”, unchanged red blood cells were detected in 44.4 % of patients, in 42.2 % of cases red blood cells were dysmorphic, and in 13.4 % of cases acanthocytes were detected. In children with erythrocyturia, who were clinically diagnosed with hereditary nephritis, dysmorphic erythrocytes prevailed — 52.2 %, in 26.1 % of patients erythrocytes were unchanged, and in 21.7 % of patients acanthocytes were identified. In children with erythrocyturia and dysmetabolic nephropathy, erythrocytes in the urine sediment were unchanged, and salt crystals were detected. Conclusions. The severity of erythrocyturia does not always correspond to the degree of alteration of red blood cell morphology. The most significant erythrocyturia is in children with hereditary nephritis; in this group the percentage of acanthocytes is highest, suggesting the presence of glomerular nephropathy. The presence of high number of dysmorphic erythrocytes is not a purely specific feature of glomerular erythrocyturia. Studying morphological characteristics of erythrocytes in the urine sediment with the help of UCF does not allow establishing the final diagnosis, but gives an opportunity to determine the tactics of further examination of the patient. A further research of the sensitivity and specificity of this method is carried out, the results of the study of morphological characteristics of erythrocytes in the urine sediment are studied in comparison with kidney biopsy.
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