Simple hematuria in children

Introduction to simple hematuria in children Where the number of red blood cells in the urine exceeds normal and there is no clear systemic and urinary diseases and their symptoms (such as edema, hypertension, renal dysfunction, etc.), simple hematuria, simple hematuria is a symptomatic diagnosis, In addition to various diseases that can cause hematuria, only the asymptomatic patients with unclear etiology and isolated hematuria (without proteinuria) are "simple hematuria". In 1979, the draft classification of kidney disease prepared by the Chinese Pediatric Nephrology Research Collaboration Group was called asymptomatic hematuria (asymptomatichematuria), and in 1981 it was revised to simple hematuria. This name is similar to the so-called "isolated hematuria" in the world. basic knowledge The proportion of illness: 0.0035% Susceptible people: children Mode of infection: non-infectious Complications: anemia, urinary tract infection, urinary incontinence

Pediatric simple hematuria

(1) Causes of the disease

Sources of hematuria can be divided into glomeruli and non-glomerular hematuria (urinary tract hemorrhage).

1. Non-glomerular hematuria There are many causes of urinary tract bleeding, and the following diseases are common.

(1) urinary malformations: common stenosis of the renal pelvis - ureteral junction, renal effusion and polycystic kidney.

(2) urinary tumors: The most common pediatrics are nephroblastoma (Wilm tumor). When hematuria occurs, most of the tumors in the abdomen can be touched. The urinary tumor is easily detected by imaging examination.

(3) high calcium urine: primary hypercalciuria can account for 1/3 to 1/5 of asymptomatic hematuria, the diagnosis mainly depends on the ratio of urinary calcium and creatinine (mg / dl), due to idiopathic hypercalciuria The incidence of family kidney stones is quite high, up to 30% to 70%, so those who have a family history of kidney stones should consider the possibility of hypercalciuria.

(4) Nutcracker phenomenon: The left renal vein passes through the angle between the aorta and the superior mesenteric artery, and the angle is too narrow. It can be compressed to cause hematuria or proteinuria. The diagnostic criteria proposed by Itan are: 1 one side of renal hemorrhage, 2 urinary calcium is normal, 3 urinary red blood cells are homogeneous, 4 renal biopsy is a small change, 5B super and CT see left renal vein dilatation, 6 left renal vein and inferior vena cava pressure difference between 5cmH2O, domestically considered B-ultrasound Or CT examination of the left renal vein distal diameter than the proximal 3 times as a diagnostic criteria, but found that the detection rate of normal children can reach 10%, and the detection rate of children with glomerular disease is as high as 30%, and most reports It is impossible to ask whether hematuria is from the left ureter. Therefore, it is difficult to diagnose the left renal vein by B-ultrasound or CT alone. It is considered that the gold index for the diagnosis of this disease is to measure the pressure difference between the left renal vein and the inferior vena cava. Left venous angiography revealed the presence of collateral veins. Although ultrasound examination can confirm the expansion of the left renal vein, it is true that the cause of renal hemorrhage is undetermined, and other kidney diseases can also be combined. Therefore, the diagnosis should be careful not to delay other Diagnosis of the disease, (5) Kidney stones: renal pelvis and renal pelvis resting stones can only have hematuria without abdominal pain or low back pain.

(6) Sports hematuria: seen after strenuous exercise, disappeared within 48 hours after rest.

(7) high oxalic aciduria: no matter the primary or secondary high oxalic aciduria is rare, in addition to hematuria, can also be kidney stones, renal calcification and renal insufficiency.

(8) Others: rare causes of renal hemangioma rupture, renal pelvic vein-kidney and spontaneous (or renal puncture) arteriovenous hemorrhage, hematuria from one side of the kidney, and quite serious, in addition to mild renal contusion Injury and renal movement, venous embolism can also cause hematuria. The above diagnosis of hematuria is quite difficult. Sometimes it is difficult to stop bleeding due to severe hematuria.

2. Glomerular hematuria in the early stage of acute nephritis and acute nephritis, hematuria, with strong diuretics and chronic renal failure, may be non-glomerular, and a small number of cases of renal stone can be expressed as glomerular hematuria IgA nephropathy is biphasic, mostly caused by glomerular prolonged chronic diseases, including acute nephritis recovery period, allergic purpura nephritis recovery period, hereditary nephritis (Alport syndrome), familial hematuria and solitary hematuria (benign Recurrent hematuria, etc., the first two diagnoses mainly rely on the past acute history and typical purpuric rash.

(1) hereditary nephritis: hematuria, a small amount of proteinuria, patients with neurological deafness, internal eye lesions, family history.

(2) Familial hematuria: Hematuria often occurs after respiratory infections, and the same nature of hematuria exists in the family.

(3) isolated hematuria: continuous microscopic intermittent glomerular hematuria, after the exclusion of hereditary nephritis and familial recurrent hematuria, clinically diagnosed as isolated hematuria, or recurrent hematuria, clinically separable For two categories: 1 recurrent gross hematuria, 2 continuous microscopic hematuria.

(4) Goal vascular disease: only manifested as hematuria.

(two) pathogenesis

Pathological changes vary from report to report. This may be related to differences in renal biopsy indications and detection methods. Cubler and Habib reported 245 cases of renal histology, 65% were IgA nephropathy; 37 of the 85 cases were examined by electron microscopy. For example, Alport syndrome, 16 patients with diffuse glomerular basement thinning, 32 patients with normal or mild non-specific changes in glomeruli, Hungary S.Turi reported 47 cases of mesangial hyperplasia in 17 cases, Alport syndrome 14 For example, 5 cases of focal hyperplasia, 3 cases of membranous proliferative nephritis, 3 cases of IgA nephropathy, 2 cases of minimal lesions and membranous nephropathy, 1 case of focal segmental sclerosis, 50 cases of biopsy results of Shanghai Children's Hospital, Mesenteric hyperplasia 27 cases (54%) with nephritis, 7 cases (14%) with IgA nephropathy, 7 cases (14%) with mild lesions, 6 cases (12%) with focal segmental nephritis, and 3 cases (6%) with IgM nephropathy. In China, simple hematuria is more common with mesangial proliferative lesions. Familial hematuria: glomerular lesions are thinning of the glomerular basement membrane (<250nm), so it is recommended that this disease be called thin basement membrane nephropathy (thin Basement membrane nephropathy), but in recent years, many basement membranes in patients with non-familial hematuria and partial hereditary nephritis have also been significantly thinned. Vascular disease: In recent years, foreign pediatric reports reported that renal biopsy pathological examination in children with asymptomatic hematuria found that some cases have C3 deposition in the glomerular intima small artery wall, and some may have IgM and C4 deposition, the lesion is similar to adult low back pain - Loin pain hematuria syndrome, glomerular mesangial membrane can be mild hyperplasia, focal sclerosis, small arterial wall transparent fibrotic intima thickening, etc., its pathogenesis is still unclear, there may be local clotting activity Increased and platelet activation, prolonged clotting time of heparin thrombin and increased serotonin in the blood in adults, the mechanism of exercise hematuria may be related to friction or hemodynamic changes in the posterior wall of the bladder, solitary Hematuria is a collective term for a group of diseases with different pathological glomerular diseases and common clinical manifestations. Kidney biopsy glomerular lesions are: normal, slightly altered, mesangial proliferative nephritis (focal, segmental or diffuse Sexually, immunofluorescence can be negative, a small amount of immunoglobulin and/or C3 deposition, IgA nephropathy and IgM nephropathy, occasionally showing anti-basement membrane nephropathy.

Simple hematuria prevention in children

At present, there is no effective prevention method, but prevention of infection, avoiding overwork and strenuous exercise can alleviate and reduce hematuria.

Simple hematuria complications in children Complications, anemia, urinary tract infection, urinary incontinence

The causes are different and there are no obvious complications. Repeated episodes can lead to anemia, urinary tract infections, and urinary incontinence.

Simple hematuria in children, common symptoms, hematuria, abdominal pain, pyuria, incontinence, urinary pain, urinary protein, urinary urgency, urinary frequency, varicocele

Simple hematuria

Clinically, there are two manifestations, recurrence and persistence, both of which are edema, hypertension, and renal insufficiency.

(1) recurrence: recurrent gross hematuria between the two episodes, normal urine examination or microscopic hematuria, the cause of hematuria is respiratory infection, severe physical activity, etc., mainly for recurrent episodes of gross hematuria, each hematuria persists The time is generally no more than 2 to 5 days; the interval between the two episodes varies from a few months or years, and the routine urine examination is normal or microscopic hematuria. Usually, there is a history of infection or strenuous exercise 1 to 3 days before the onset of gross hematuria. A small number of sick children with hematuria may be accompanied by abdominal pain or low back pain. The renal pelvis and renal pelvis resting stones may have only hematuria without abdominal pain or low back pain. Generally, X-ray abdominal plain films and B-mode ultrasonography can be found.

(2) Persistence: Most of the hematuria under continuous microscopic examination is found during physical examination or routine urine examination for other diseases. The urine protein does not exceed 1g/d, and the number of red blood cells in the urine may fluctuate without any other symptoms or signs. It was discovered by chance, so it is difficult to determine the onset date and course of disease.

2. Disease characteristics

(1) hereditary nephritis: persistent or recurrent microscopic or gross hematuria. The onset of hematuria is intermittent, accompanied by microalbuminuria. Later, it gradually turns into continuous microscopic hematuria. Hematuria is aggravated in the upper respiratory tract infection. Gross hematuria, urine protein can also be increased (generally no more than 1g / 24h), 30% to 40% of patients with neurological deafness, 15% to 20% have internal eye lesions (cataract, conical crystals and fundus lesions, etc.), family There may be chronic kidney disease, deafness, and internal eye disease.

(2) familial hematuria: also known as familial benign hematuria, clinical manifestations of continuous microscopic hematuria, intermittent gross hematuria, gross hematuria often occurs after respiratory infection, blood pressure, normal renal function, without proteinuria, the main basis for diagnosis is There is the same nature of hematuria in the family. One of the parents has hematuria, which is of great help to the diagnosis. The family members should be tested for hematuria multiple times, at least 3 to 4 times. One urine test is not enough to rule out the disease.

(3) Goal vascular disease: clinically no symptoms of severe low back pain in adults, only manifested as hematuria, including recurrent gross hematuria, recurrent gross hematuria with continuous microscopic hematuria.

(4) hypercalciuria: hematuria is the most common symptom of hypercalciuria, usually asymptomatic microscopic hematuria, but also has a gross hematuria, even for several days, some children with hematuria with hematuria Or suprapubic pain, red blood cell morphology in hematuria is non-glomerular, in addition to hematuria, this disease can also cause a variety of urinary symptoms, such as urinary pain, frequent urination, urgency, daytime urinary incontinence, enuresis, pyuria and repeated urinary Road infections, etc.

(5) nutcracker phenomenon: also known as left renal vein compression syndrome (left renal vein entrapment syndrome), in adolescence, body length increase, vertebral body overstretched, rapid changes in body shape, etc., walking in the abdomen The angle formed by the aorta and superior mesenteric artery (usually this angle 45 ° ~ 60 °) narrowed, during which the left renal vein was compressed, causing hemodynamic changes, one of the important consequences of left kidney bleeding ( There may also be testicular veins or ovarian venous congestion and varicocele that are introduced into the left renal vein. The proportion of evoked patients in hematuria is unknown, but it has been reported in 31 patients with non-glomerular hematuria. (In addition to stones, high urinary calcium, tumors, infections), 15 cases are caused by this disease. This type of hematuria is characterized by one-sided (left) renal hemorrhage, and the urinary red blood cells are non-glomerular, and the degree of bleeding Different, can be detected for asymptomatic hematuria in urine screening, but also for obvious gross hematuria, and can be repeated, sometimes with exercise as a cause, some with left waist discomfort or abdominal pain, children can complain of abdominal pain and often prone position .

Pediatric simple hematuria examination

There is no change in renal insufficiency, normal urine examination during the interictal period or microscopic hematuria, and the number of red blood cells in the urine may fluctuate.

Hematuria

It refers to the red blood cell excretion in the urine is more than normal, only found under the microscope, the red blood cell increase, called microscopic hematuria; the naked eye can see the urine is "washing water" color or blood sample or even clot, called "human hematuria "The color of gross hematuria is related to the pH of urine. Neutral or weakly alkaline urine is bright red or washed with water. Acidic urine is rich in tea or soot water. The method and diagnostic criteria for microscopic hematuria are currently Not yet unified, common standards are:

(1) 10 ml of fresh urine in the middle of centrifugation, centrifuged at 1500 rpm for 5 min, and placed a drop of the sediment on a slide. Observed under high magnification, the red blood cells were >3/Hp.

(2) urinary sediment red blood cell count>8×106/L, glomerular hematuria: refers to the uneven size of red blood cells, different forms, polymorphic red blood cell morphology is budding, bag-shaped, target shape, large cells, broken red blood cells and Cytoplasmic light staining, etc., the author proposed that ring type, spore shape and perforation type 3 (G1 type) is characteristic of glomerular hematuria. Clinically, when polymorphic red blood cells account for more than 30% of total red blood cells in urine, Or G1 type>5%, count>8000ml, can be diagnosed as glomerular hematuria.

2. Urinary calcium,

Determination of uric acid in hypercalciuria mainly depends on the measurement of urinary calcium. The amount of calcium excreted in the urine exceeds normal (the normal upper limit is <4mg/kg per day). It can be seen in many cases. For children with hematuria, when the red blood cell morphology is urinary Non-glomerular, should pay attention to the possibility of exclusion of high urinary calcium, at this time possible urine screening test, that is, random urine, urinary calcium / urine creatinine (mg / mg), if 2h urinary calcium after meals (mg/dl) and creatinine (mg/dl) ratio 0.2 (<6 months for infants > 0.8, 6 to 12 months > 0.6) suggest high urinary calcium, can diagnose hypercalciuria, high urinary calcium The diagnosis requires 2 or more times 24h urinary calcium measurement, such as 4mg / (kg · d) can be diagnosed, should also refer to the medical history, laboratory tests (such as blood calcium, phosphorus, blood pH, parathyroid hormone, etc.) Secondary or idiopathic, high oxalic acid diagnosis was determined by uric acid, normal at 10 ~ 50mg / d.

3. Urine protein

With microalbuminuria, the increase in urinary protein generally does not exceed 1g/24h.

4. Renal biopsy

Types of glomerular lesions are normal, slightly altered, mesangial proliferative nephritis (focal, segmental or diffuse), immunofluorescence can be negative, a small amount of immunoglobulin and / or C3 deposition, IgA nephropathy and IgM nephropathy Occasionally, the performance of anti-basement membrane nephropathy, renal biopsy pathological examination of children with glomerular vascular disease can be found in the glomerular inferior cerebral arteriolar wall with C3, IgM and C4 deposition, glomerular mesangial can be mild hyperplasia, focal Hardening, small arterial wall transparent fibrotic intima thickening, etc., do a variety of imaging examination to determine the cause of hematuria, general X-ray abdominal plain film and B-mode ultrasound can find renal pelvis and renal pelvis static stones, urinary Tumors are easily detected by imaging examination, non-glomerular hematuria such as urinary malformations, often due to renal pelvis-ureteral junction stenosis caused by renal effusion and polycystic kidney, imaging examination, such as B-mode ultrasound can do most Diagnosis, nutcracker phenomenon: B-ultrasound and CT can be seen in the left renal vein dilatation. It has been considered in China that B-ultrasound or CT examination of the left renal vein distal diameter is 3 times larger than the proximal end as the diagnostic criteria, but the detection rate of normal children is found after sputum. Up to 10%, and kidney The detection rate of children with small ball disease is also as high as 30%, and most reports can not ask whether hematuria comes from the left ureter. Therefore, it is difficult to diagnose the left renal vein by B-ultrasound or CT alone. It is considered that the disease is currently considered. The gold index for diagnosis is to measure the pressure difference between the left renal vein and the inferior vena cava. Left venous angiography shows the presence of collateral vein. Although the ultrasound can confirm the left renal vein dilatation, it is true that the cause of renal hemorrhage is undetermined, while other kidney diseases This phenomenon can also be combined, so the diagnosis should be careful not to delay the diagnosis of other diseases, in addition to mild renal contusion and kidney movement, venous embolism caused by hematuria, diagnosis is quite difficult, angiography can be diagnosed.

Diagnosis and diagnosis of simple hematuria in children

diagnosis

The diagnosis of simple hematuria must first exclude all kinds of diseases that can cause hematuria. For asymptomatic, isolated hematuria (without proteinuria), it can be diagnosed as simple hematuria, except in patients with non-glomerular hematuria. High urinary calcium, tumors, infections, stones, should be thought of the possibility of this disease, can be diagnosed by means of B-mode ultrasound, angiography and CT examination, history should be detailed in the children and family history of kidney disease, hematuria, stones History; for recurrent people should pay attention to the cause of seizures, hereditary nephritis in addition to clinical hematuria persistence or recurrence, with neurological deafness, internal eye lesions, family may have chronic kidney disease, deafness, internal eye disease, etc., there are The typical pathological changes of glomeruli, stratification or loosening of the basement membrane are net basket-like changes. This change has important diagnostic significance. The main reason for the diagnosis of familial hematuria is that there is the same nature of hematuria in the family, and one of the parents has hematuria. Diagnostic help is great, check the family members of the hematuria should be repeated urine, at least 3 to 4 times, 1 urine test is not enough to rule out the disease.

Differential diagnosis

The following diseases must be identified when diagnosing simple hematuria in children.

1.IgA nephropathy

IgA nephropathy is a glomerular disease characterized by significant IgA deposition in the glomerular mesangial area. Most of the children present with recurrent hematuria. In addition to severe glomerular deformation, urinary red blood cells may also be present during the attack. Non-glomerular, some children with elevated serum IgA, the diagnosis depends on renal biopsy immunofluorescence (see IgA nephropathy section for details).

2. Benign familial hematuria

There is a family history, with simple hematuria as a clinical feature, pathological electron microscopy shows glomerular basement membrane (see benign familial hematuria section), also known as thin basement membrane disease.

3.Alport syndrome

In the early stage, only simple hematuria can be seen, but according to family history, neurological high-frequency deafness, progressive renal dysfunction and other characteristics can be distinguished. At present, X-linked hereditary, skin biopsy, and detection of type IV collagen chain can help diagnose.

4. Idiopathic hypercalciuria (idiopathic hypercalciuria)

Idiopathic hypercalciuria can account for 1/3 to 1/5 of asymptomatic hematuria and is one of the important causes of simple hematuria in children. Of the 83 patients with isolated hematuria reported by Stapleton, 23 (27.7%) Clearly for high urinary calcium disease, high urinary calcium disease detection rate varies from place to place, Moore reported that the incidence rate of children in the United States was 2.9% to 6.2%; Peking Union Medical College Hospital examined 638 cases of healthy children found high urinary calcium in 11 cases (1.7%); this difference may be related to regional, ethnic, age, diet and vitamin D intake. Diagnosis of idiopathic hypercalciuria should exclude adrenal cortical disease, parathyroid disease, renal tubular acidosis, sponge Kidney and taking corticosteroids and other secondary hypercalciuria, because the incidence of idiopathic hypercalciuria family kidney stones is quite high, up to 30% to 70%, so ask the family history of kidney stones should consider high The possibility of calcium uremia is divided into two categories according to whether it is accompanied by increased blood calcium. One type is accompanied by increased blood calcium, mainly seen in vitamin D poisoning, hyperparathyroidism, infant idiopathic hypercalcemia, etc. Normal blood calcium and increased urinary calcium, can be seen in Fanconi syndrome, distal renal tubular acid Poisonous, or secondary to corticosteroids, diuretic application, or long-term brakes due to bone disease, burns, and idiopathic hypercalciuria with unknown etiology, causing simple hematuria is mainly idiopathic Urinary calcium disease, the cause of this disease is unknown, according to the pathogenesis can be divided into two types: one is the increase in intestinal absorption of calcium, and the second is the lack of calcium absorption by the renal tubules.

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