1.What is hematuria in children?
Hematuria (hematuria) is the presence of more than normal numbers of red blood cells in the urine. Microscopic hematuria refers to normal urine color, which can only be determined by microscopic examination. The number of red blood cells per high-powered field of view in centrifugal sedimented urine is ≥3, or the number of red blood cells per high-powered field of view in non-centrifugal urine is ≥1 or the urine sediment count exceeds 8,000 per milliliter or the urine red blood cell count exceeds 100,000 in 1 hour, or the urine red blood cell count exceeds 500,000 in 12 hours; hematuria with the naked eye It is hematuria that is the color of washed flesh water or blood, which is visible to the naked eye. Hematuria is a common symptom in pediatrics, often suggesting urological disorders, which needs to be clinically characterized and localized to analyze its etiology in order to guide treatment.
2. What is the incidence of hematuria in children?
Overseas survey found that the incidence of hematuria in children is 0.1% in men and 0.7% in women, and the survey in China in 1982 was 2.63%, and now there is an increasing trend. The urine screening of children is unified by using visual triple test paper (urine protein, occult blood, nitrite) and single test strips, and the results show that the positive rate of asymptomatic microscopic hematuria is 0.42%.
3.Does dark urine in children necessarily mean hematuria?
The dark color of urine or red color needs to be clarified whether it is hematuria: the color of normal human urine is generally light yellow, and the shade of color is related to the concentration of urine, which may be affected by certain foods and drugs, such as carrots, chili peppers, tomatoes, purple dragon fruit or drugs such as rifampin, vitamin B2, rhubarb, huanglian, senna, etc., that is, the color of urine changes with the color of certain food pigments and drugs. Therefore, dark urine or red urine is not necessarily hematuria, that is, to identify true hematuria and pseudohematuria, the method of identification is to check the number of red blood cells in the urine routine or urine sediment, such as no red blood cells in the urine that is not hematuria.
4.Does a positive occult blood test in children’s urine necessarily mean hematuria?
The principle of the current urine occult blood test is to use the oxidation of hemoglobin and the color reaction of the test paper for semi-quantification, while the presence of free hemoglobin, myoglobin and peroxidase in the urine can be a false positive (no red blood cells in the urine that is not hematuria). And 1.8% to 5.8% of healthy people have positive urine analysis for occult blood, so urine occult blood and microscopic examination are often not parallel. If a positive occult blood is found during a routine urine examination, it needs to be treated calmly and a urine sedimentation test needs to be performed to determine if it is hematuria. Therefore, positive urine occult blood is not necessarily hematuria, while urine occult blood must be positive in patients with hematuria. The examination of urine occult blood is only a preliminary screening of hematuria and cannot be used as a basis for confirming the diagnosis of hematuria, and urine sediment microscopy should be done when hematuria is suspected.
5.How to distinguish whether hematuria in children comes from glomerular or extra-glomerular sources?
Morphological examination of red blood cells in urine is the most common method to distinguish glomerular from non-glomerular hematuria. When the red blood cells in urine show uniform size, smooth surface, similar to the red blood cells in normal unprocessed blood, biconcave mirror shape, and normal cytoplasmic hematocrit content, it is called homogeneous red blood cell urine, i.e. non-glomerular hematuria; when the red blood cells in urine show ring shape similar to fried doughnut shape, spiny, serrated, crinkled, target shape, shadow shape, mouth shape, etc., it is called homogeneous red blood cell urine. When the red blood cells in the urine show ring shape similar to fried doughnut, spike shape, jagged shape, crinkle shape, target shape, shadow shape, mouth shape, etc., it is called polymorphic red blood cell urine that is glomerular hematuria. At present, this test has been commonly carried out in China, which is important for the localization and diagnosis of hematuria.
6.What are the causes of hematuria in children?
98% of hematuria is caused by urinary system diseases (including organic and functional changes), while 2% of hematuria is caused by systemic diseases or lesions in adjacent organs of the urinary system. There are two major categories of glomerular and non-glomerular hematuria.
(1) Glomerular hematuria: refers to hematuria originating from the glomerulus, and is seen in: (1) primary glomerular diseases, such as acute, prolonged, chronic, and acute glomerulonephritis, nephrotic syndrome, IgA nephropathy, etc.; (2) secondary glomerular diseases, such as lupus nephritis, purpura nephritis, hepatitis B-associated nephritis, etc.; (3) hereditary glomerular diseases, such as hereditary nephritis (Alport syndrome), thin basement membrane nephropathy (familial benign hematuria); ④ transient hematuria after strenuous exercise.
(2) Non-glomerular hematuria.
A, hematuria from the urinary system below the glomerulus: ① acute or chronic infection of the urinary tract; ② stones in the kidney, ureter and bladder; ③ tuberculosis; ④ idiopathic hypercalciuria; ⑤ left renal vein compression syndrome (or the phenomenon of Hu pick clip); ⑥ congenital urinary tract malformations such as renal cysts, double ureteral malformations, bladder diverticulum; ⑦ congenital renal vascular malformations such as arteriovenous fistula, hemangioma; ⑧ drug-induced kidney and bladder injury such as cyclophosphamide, indomethacin, mannitol, sulfonamide, gentamicin; ⑨ tumor, trauma and foreign body; ⑩ renal vein thrombosis.
B, bleeding caused by systemic diseases, such as thrombocytopenic purpura, leukemia, aplastic anemia, hemophilia.
7.Which drugs are likely to cause hematuria?
Clear drugs include aminoglycoside antibiotics (such as gentamicin, kanamycin, etc.), sulfonamides (such as cotrimoxazole, etc.), first- or second-generation cephalosporins (such as Pioneer IV, etc.), other drugs such as aspirin, cold and flu, etc. and uncertain drugs, all of which can cause renal damage and hematuria. For children with hematuria using such drugs, urinary routine should be checked to find urinary epithelial cells or tubular type or renal tubular In children with hematuria caused by the use of such drugs, urinary routine should be checked to find the urinary epithelial cells or tubular type or renal tubular function, such as increased urinary NAG enzyme or urinary RBP.
8.How is hematuria in children caused?
The pathogenesis of non-glomerular-derived hematuria in children is divided into non-glomerular-derived hematuria and glomerular-derived hematuria: the pathogenesis of non-glomerular-derived hematuria is single, mainly related to vascular injury, abnormal coagulation, infection, inflammation and other factors; while the pathogenesis of glomerular-derived hematuria is complex, and there is no unified theory that can fully explain its cause, so the source of hematuria is still unclear. Current research has focused on abnormalities of the glomerular filtration membrane and the red blood cells themselves.
9.When should a kidney biopsy be done for hematuria in children?
If the number of centrifugal urine red blood cells is more than 10 per high-powered view (3 times within 2 weeks, at least 2 times above 10), or for patients with hematuria at a young age (especially <1 year) or with a family history of hematuria, while persistent or intermittent for more than 6 months and still not clearly diagnosed; or persistent glomerular hematuria >1 month or for persistent glomerular hematuria with proteinuria, with hypertension and azotemia or acute renal Renal biopsy may be considered in cases of persistent glomerulonephritis with proteinuria, hypertension and azotemia or acute kidney injury with persistent hypocomplementemia. The purpose of renal biopsy is to clarify the diagnosis, adjust the treatment and determine the prognosis.
10.How is hematuria diagnosed in children?
The diagnosis of hematuria is based on microscopic examination, that is, the number of red blood cells per high-powered field of view ≥ 3 in centrifuged precipitated urine or ≥ 1 in non-centrifuged urine or the number of red blood cells per high-powered field of view ≥ 1 or the urine sediment count exceeds 8,000 per milliliter or the urine red blood cell count exceeds 100,000 in 1 hour or 500,000 in 12 hours or hematuria in the naked eye.
11.Diagnostic process of hematuria in children?
(1) Identify whether it is true hematuria: the identification is to check the red blood cell count or urine sediment in urine routine, if there are red blood cells in urine, it is true hematuria.
(2) Judging the source of hematuria after it is clear that it is true hematuria.
(3) Combine with medical history and physical examination for comprehensive analysis.
12.How to treat hematuria in children?
The cause of hematuria is complex, so go to the hospital for examination and clear diagnosis as soon as possible, and then carry out corresponding treatment according to different causes.
In case of non-glomerular hematuria, such as urinary tract infection, anti-infection treatment is needed; in case of glomerular hematuria, which is clinically manifested as simple hematuria, microscopic hematuria does not exceed 6 months and is not accompanied by proteinuria, no special treatment is needed; in case of persistent microscopic hematuria for more than 6 months, ACEI or ARB treatment or proprietary Chinese medicine without kidney damage, such as our self-developed Kidney 1, can be considered; in the course of drug treatment, caution should be exercised in using drugs that cause In the course of drug therapy, use drugs that cause hematuria with caution; consider using immunosuppressive drugs in severe cases.
In conclusion, if hematuria is found, early examination, clear diagnosis and corresponding treatment according to different etiologies are needed, and patients who do not need special treatment need to be reviewed regularly, and if the condition worsens, they need to go to a pediatric nephrology specialist for treatment.