Pediatric hematuria

　　There are many causes of hematuria in children, which are divided into two major categories: glomerular and non-glomerular hematuria. The specific causes are described as follows.

　　Firstly, glomerular hematuria

　　Refers to hematuria originating from the glomerulus.

　　1. Primary glomerulonephritis:The most common cause of hematuria in children. Such as various acute, chronic, and persistent glomerulonephritis, rapid progressive nephritis, nephrotic syndrome, IgA nephropathy, and others. In addition to hematuria, it also has the manifestations of proteinuria, edema, hypertension, and renal insufficiency.

　　2. Secondary glomerulonephritis:Commonly seen are hepatitis B or C virus-related nephritis, purpura nephritis, lupus nephritis, nodular arteritis, hemolytic uremic syndrome, infective endocarditis-related nephritis, and others. In addition to hematuria, they often accompany the clinical manifestations of the primary disease.

　　3. Familial genetic glomerular disease:Commonly seen in hereditary nephritis (Alport syndrome), thin basement membrane nephropathy.

　　4. Simple hematuria:Clinically, it is only manifested as persistent or recurrent microscopic hematuria, with or without episodic gross hematuria, without other symptoms such as edema, hypertension, and renal function impairment.

　　5. Transient hematuria after partial strenuous exercise.

　　Secondly, non-glomerular hematuria

　　Refers to hematuria originating from the renal tubules, interstitium, or urinary tract (including the collecting system, ureter, bladder, and urethra) as well as systemic diseases.

　　1. Urinary tract infection:Including pyelonephritis, renal tuberculosis, cystitis, and others. The pathogens can also be caused by bacteria, viruses, mycoplasma, fungi, parasites, and so on.

　　2. Urinary system calculi:Renal calculi, bladder calculi, urethral calculi.

　　3. Idiopathic hypercalciuria.

　　4. Medications and chemical substances:Antibiotics (such as aminoglycosides, cephalosporins, penicillin, sulfonamides), acetylsalicylic acid, anticoagulants (heparin, dicoumarin), cyclophosphamide, indomethacin, cold medicine, phenol, heavy metals (mercury, arsenic, lead), and others.

　　5. Vascular lesions:Walnut phenomenon (left renal vein compression syndrome), renal vein thrombosis, arteriovenous fistula of the kidney.

　　6. Urinary tract anomalies:Polycystic kidney, horseshoe kidney, spongy kidney, bladder diverticula, hydronephrosis, and others.

　　7. Tumor:Nephroblastoma, renal embryoma, leukemia.

　　8. Trauma:Such as trauma, surgery, instrument injury, urethral foreign bodies, and others.

　　9. Lesions of adjacent organs:Such as appendicitis, pelvic inflammatory disease, and others.

　　10. Systemic diseases:Thrombocytopenic purpura, hemophilia, neonatal natural hemorrhagic disease, and others.

　　The causes of pediatric hematuria are diverse, and the symptoms of complications in different diseases vary. The specific symptoms of complications are described as follows.

　　One, common diseases of glomerular hematuria

　　1. Isolated hematuria varies depending on the etiology. Generally, there are no obvious complications, and recurrent episodes can lead to anemia, and may be complicated by urinary tract infections, urinary incontinence, and others.

　　2. Patients with Alport syndrome often have many non-specific lesions, such as thyroid disease, IgA deficiency, posterior pole optic neuritis, ascending aortic aneurysm, anal and rectal malformations, and mental illness.

　　3. Some patients with IgA nephropathy may develop renal insufficiency, hypertension, hypoalbuminemia, and a few may present with rapidly progressive nephritis.

　　4. Acute nephritis can cause acute充血性心力衰竭, hypertensive encephalopathy, acute renal failure, and secondary bacterial infection.

　　5. Purpura nephritis can cause complications such as rash, arthritis, and hypertension.

　　6. Lupus nephritis is prone to complications such as infections, cardiovascular complications, and femoral head necrosis.

　　7. A few children with familial benign recurrent hematuria may develop renal insufficiency, with reports of 10% of children having deafness, which is a high-frequency hearing impairment.

　　Two, common diseases of non-glomerular hematuria

　　1. Complications of urinary tract infections include renal papillary necrosis, perinephritis, perinephric abscess, infectious renal calculi, and gram-negative bacillary sepsis.

　　2. Idiopathic hypercalciuria often complicates urinary tract infections, urinary tract stones, secondary hyperparathyroidism, osteoporosis, fractures, muscle weakness, and others.

　　The clinical manifestations of pediatric hematuria itself are not specific, mainly the corresponding manifestations of the primary disease or accompanying symptoms related to hematuria.

　　One, medical history

　　1. The presence and timing of preceding infection, such as acute streptococcal infection followed by nephritis, often has a clear history of preceding illness, with hematuria appearing 10 to 14 days after infection; while IgA nephropathy, respiratory symptoms and hematuria occur almost simultaneously, generally not exceeding 3 days.

　　2. Recent history of use of aminoglycoside antibiotics, sulfonamides, and other drugs.

　　3. The history of trauma.

　　4. The history of contact with rodents is extremely important for the diagnosis of epidemic hemorrhagic fever.

　　5. A history of skin purpura supports purpura nephritis.

　　6. Individuals with a history of hepatitis should be excluded from hepatitis-related nephritis.

　　7. The presence or absence of hematuria, renal failure, deafness, and eye diseases in the family provides clues for hereditary nephritis and familial benign hematuria.

　　8. A family history of hemorrhage is helpful for the diagnosis of hemophilia.

　　Two, accompanying symptoms

　　1. Obvious urinary tract irritation symptoms are commonly seen in urinary system infections (but in small infants, they may only present with fever, refusal of food, crying, and failure to gain weight), followed by attention to exclude renal tuberculosis involving the lower urinary tract and hypercalciuria.

　　2、肾区绞痛要考虑泌尿系结石。

　　2. Renal colic should be considered for urinary system stones.

　　3. Thin and tall body type with occasional left abdominal pain and back pain should be considered for idiopathic renal hemorrhage.

　　4. Renal mass should be considered for renal tumor, polycystic kidney, renal hydronephrosis, etc.

　　5. With hepatosplenomegaly and corneal K-F ring, consider hepatolenticular degeneration.

　　6. With systemic damage in multiple systems, consider systemic lupus erythematosus, etc.

　　7. With unexplained fever, weight loss, anemia, and hemoptysis, suspect pulmonary hemorrhagic nephritis syndrome.

　　8. With fever, facial, neck, and upper chest erythema, and gradually appearing skin hemorrhagic spots, hypotension, shock, oliguria, consider epidemic hemorrhagic fever.

　　9. With gastrointestinal symptoms, followed by hemolytic anemia and thrombocytopenia, consider hemolytic uremic syndrome.

　　How to prevent pediatric hematuria

　　What laboratory tests need to be done for pediatric hematuria

　　Diagnosis of pediatric hematuria: first, determine whether it is true hematuria; second, determine the source of hematuria; finally, determine the possible etiology of hematuria.

　　1. Determine whether it is true hematuria

　　When the child's urine turns red, it is necessary to exclude pseudohematuria:

　　1. Some metabolic products in urine, such as porphyrinuria, homogentisic aciduria (tyrosine metabolism disorder), bilirubin, uric acid, and drugs such as phenol red, aminopyrine, rifampicin, iron, methyldopa, metronidazole, furazolidone, pyrimidine, etc., can make urine red; certain food or vegetable pigments such as beetroot, blackberry, and food color can also cause red urine. Urinary routine occult blood and microscopic red blood cell tests are all negative.

　　3. Non-urinary tract bleeding, such as vaginal or lower gastrointestinal bleeding mixed in, menstrual contamination.

　　Second, localization analysis of hematuria

　　1. Gross observation:Dark red urine often comes from the renal parenchyma or renal pelvis; bright red or with blood clots usually indicates non-glomerular disease bleeding; larger blood clots may come from bladder bleeding; blood dripping from the urethral orifice may come from the urethra.

　　2. Urine three-cup test:During the continuous urination of the child, urine from the initial, middle, and final stages is collected separately using three glass cups, and then blood urine examination is performed. Initial blood urine is seen in urethral diseases; terminal blood urine is seen in bladder neck, trigone, posterior urethra, and prostatic diseases; whole course blood urine suggests kidney, ureter, and bladder diseases.

　　3. Urinalysis:When hematuria is accompanied by a large amount of protein (>2+), consider that the lesion is in the glomerulus. If casts, especially red cell casts, are found in the urine sediment, it is mostly a renal parenchymal lesion; if hematuria is accompanied by a large amount of uric acid, oxalate, or phosphate crystals, it is necessary to exclude hypercalciuria and stones.

　　4. Urinary red blood cell morphology examination:When red blood cells in urine show morphological changes and are accompanied by hemoglobin loss, i.e., deformed red cells are predominant, it is glomerular hematuria. It is generally believed that the mechanism of glomerular hematuria is that red blood cells are squeezed through the damaged glomerular basement membrane and affected by the intratubular osmotic pressure, pH, and metabolic substances (fatty acids, hemolytic lecithin, and bile acids, etc.) during the passage through the renal tubules, resulting in changes in shape and size; when the morphological appearance of red blood cells in urine is basically normal and uniform, it is non-glomerular hematuria. The uniform red cell hematuria is caused by bleeding from the urinary tract blood vessels, so the red blood cell morphology is normal. Red blood cells with severe deformation (circular, blast, perforated) >30% are called glomerular hematuria.

　　Three. Selection of laboratory tests and special examinations

　　1. Determined to be non-glomerular hematuria

　　(1) Midstream urine culture to find evidence of urinary tract infection.

　　(2) Urinary calcium and 24-hour urinary calcium determination.

　　(3) If a systemic bleeding disorder is suspected, relevant blood tests such as platelets and prothrombin time need to be performed.

　　(4) If tuberculosis is suspected, blood sedimentation, tuberculin skin test (PPD), and X-ray examination are required.

　　(5) Routine B-ultrasound examination can observe kidney morphology, the presence of stones, malformations, masses, compression of the left renal vein, and renal vein thrombosis.

　　(6) Abdominal X-ray can observe non-radio-opaque stones and calcified foci, intravenous pyelography, voiding cystography, and retrograde ureterography can be selected according to need.

　　(7) CT diagnosis of space-occupying lesions is highly sensitive, but due to the rarity of hematuria caused by tumors in children, the cost is high, so it is less commonly used.

　　(8) If renal arteriography is needed, digital subtraction angiography can be used to determine the presence of venous fistula, angioma, and thrombosis.

　　(9) Cystoscopy can directly observe the side of the kidney or the bleeding site, range, and nature of the lesion in the bladder, and can take tissue for pathological examination. Since it is a traumatic examination, it is only performed when there are strict indications.

　　2. Determined to be glomerular hematuria

　　(1) 24-hour urine protein quantification determines the presence of proteinuria, and if present, further examination of blood albumin/globulin and blood lipid levels is required.

　　(2) Tests such as blood antistreptolysin O (ASO), complement, antinuclear antibody, and hepatitis B-related antigens can be used to differentiate the nature of nephritis.

　　(3) Blood urea nitrogen, creatinine, and内生肌酐清除率 reflect the degree of renal damage.

　　(4) Ultrasound observation of kidney size and internal echo.

　　(5) Renal biopsy is of great help in clarifying the etiology of glomerular hematuria, guiding treatment, and judging the prognosis. The following indications can be considered: persistent microscopic hematuria or gross hematuria lasting for more than 6 months; associated with significant proteinuria and excluding post-streptococcal glomerulonephritis; associated with hypertension and azotemia; associated with persistent low complement levels; with a family history of nephritis or deafness.

　　Children with hematuria should eat blood-cooling and hemostatic foods; avoid spicy and irritating, fried and greasy foods; and have a low-salt diet. The specific dietary precautions are as follows.

　　Firstly, Foods to Eat for Patients

　　1. Patients should eat more blood-cooling and hemostatic foods such as马兰头、鲜藕、荸荠、荠菜、冬瓜、西瓜、莲子, etc.

　　2. Persimmons and persimmon paste, apples, pears, and oranges should be eaten more.

　　3. Foods such as螺、蚶子、淡菜、鳖、鲍鱼、河蚌、海参、海蜇, etc., have certain therapeutic effects and can be selected more often.

　　Secondly, Foods to Avoid for Patients

　　For those with hematuria, especially renal hematuria, attention should be paid to rest in daily life, and not be too tired. Labor and rest should be combined. Avoid strenuous exercise, and take walking, boxing, and exercises as the main form of exercise. Prevent colds and infections, and develop the habit of drinking more water. The principles of dietary taboos should be mastered as follows:

　　1. Avoid spicy and irritating foods such as scallions, garlic, ginger, chili, and alcohol; smoke less or not at all.

　　2. Avoid fried and greasy foods, and do not eat roasted foods. It is advisable to eat less warm and hot foods.

　　3. Avoid foods such as shrimps, crabs, beef, mutton, and dog meat, and eat less seafood, soy products, animal internal organs, and skin.

　　4. Those with edema should have a low-salt diet.

　　The treatment of pediatric hematuria mainly focuses on the treatment of the primary disease according to different etiologies.

　　If it is only simple microscopic hematuria, the prognosis is generally good, no medication is needed, but follow-up is required, once a year (in the United States) or every 3-6 months. Therefore, it is recommended to 'manage' rather than treat children with such diseases. Management includes: diagnosis, treatment, patient/parent education, life guidance, and the establishment of follow-up plans. Instruct the child to have regular follow-up examinations.

　　In summary, there are not many new developments in pediatric hematuria, and in clinical practice, it should be noted that the importance of etiological diagnosis of hematuria is far greater than the treatment of hematuria. However, attention should be paid to the 'insufficiency' and 'excess' of related examinations in the diagnostic process. For children with hematuria without a clear etiology, regular follow-up is particularly important. Based on the current examination, combined with follow-up examination, a 'three-dimensional' diagnosis should be made. For different children, corresponding follow-up plans and contents should be formulated.