Hematuria is defined as ≥3 red blood cells per high-powered field of view in centrifuged precipitated urine, or more than 1 in non-centrifuged urine or more than 100,000 in 1-hour urine red blood cell count, or more than 500,000 in 12-hour urine sediment count, all indicating an abnormal increase in red blood cells in urine, and is a common urological symptom, and most patients are found to have hematuria during physical examination, however, clinical diagnosis of hematuria is not based on positive urine occult blood (BLD+) as a criterion However, clinical diagnosis of hematuria is not based on positive urine occult blood (BLD+), BLD is only an indicator for screening hematuria. Hematuria can be caused by bleeding from any part of the urinary system through urinary discharge, which is manifested as a deepening of urine color visible to the naked eye called carnal hematuria, and another kind is not visible to the naked eye, but can be found by microscopic examination, called microscopic hematuria, and most of what we see in the clinic is microscopic hematuria. In general, most of them are medical hematuria under 40 years old, and more surgical hematuria over 40 years old.
What are the causes of hematuria?
1.Kidney and urinary tract diseases
(1) Glomerulonephritis Acute and chronic glomerulonephritis, common glomerular diseases in our hematuria are IgA nephropathy and thylakoid proliferative nephritis.
(2) Urinary system infections Acute and chronic pyelonephritis, acute cystitis, urethritis, urinary tuberculosis, urinary mycobacterial infections, etc.
(3) Stones Stones in the renal pelvis, ureter, bladder, urethra, or any part of the kidney can easily cause both hematuria and secondary infection when the stones move through the urinary tract epithelium. Large stones can cause urinary tract obstruction and even renal function damage.
(4) Tumors Malignant tumors in any part of the urinary system or malignant tumors in neighboring organs can cause hematuria when they invade the urinary tract.
(5) Trauma is a violent injury to the urinary system.
(6) Congenital malformation Polycystic kidney, congenital ultra-thin glomerular basement membrane nephritis, Nutcracker phenomenon (the disease is caused by congenital malformation of blood vessels causing compression of the left renal vein that travels between the abdominal aorta and superior mesenteric artery, resulting in intractable microscopic hematuria. The right renal vein injects directly into the inferior vena cava, while the left renal vein must cross the angle formed by the abdominal aorta and superior mesenteric artery to inject into the inferior vena cava. Normally, this angle is 45°-60°, but if it is congenitally too small or filled with mesenteric fat, enlarged lymph nodes or peritoneum, it can cause nutcracker phenomenon. The diagnosis is based on CT, ultrasound, and renal venography. Treatment must be surgically corrected).
2.Systemic diseases
(1) Bleeding disorders Thrombocytopenic purpura, allergic purpura, hemophilia, leukemia, malignant histiocytosis, aplastic anemia, etc.
(2) Connective tissue diseases systemic lupus erythematosus, dermatomyositis, polyarteritis nodosa, scleroderma, etc.
(3) Infectious diseases Leptospirosis, epidemic hemorrhagic fever, filariasis, infectious bacterial endocarditis, scarlet fever, etc.
(4) Cardiovascular diseases Congestive heart failure, renal embolism, renal vein thrombosis.
(5) Endocrine metabolic diseases gout kidney, diabetic nephropathy, hyperparathyroidism.
(6) Physicochemical factors such as food allergy, radiation exposure, drugs (such as sulfonamide, phenol, mercury, lead, arsenic poisoning, massive infusion of mannitol, glycerol, etc.), toxins, after exercise, etc.
3.Neighboring organ disease
Tumors of uterus, vagina or rectum invade the urinary tract.
What tests are needed to detect hematuria?
1.Localization analysis of hematuria
The following three types of hematuria can be distinguished by the urine three-cup test.
(1) Primary hematuria Hematuria is only seen at the beginning of urination and the lesion is mostly in the urethra.
(2) Terminal hematuria Hematuria occurs at the end of urination and the lesion is usually in the bladder triangle, bladder neck or posterior urethra.
(3) Complete hematuria Hematuria occurs during the whole process of urination, and the bleeding site is mostly in the bladder, ureter or kidney.
2.Routine examination methods
(1) Tubular pattern in urine sediment Especially the red cell tubular pattern indicates that the bleeding comes from the renal parenchyma and is mainly seen in glomerulonephritis.
(2) Urine protein measurement Hematuria with more severe proteinuria is almost always a sign of glomerular hematuria.
(3) Urine containing immunoglobulin in a granular tubular form (IGM).
(4) Urine red blood cell morphology Examination of urine sediment with bitemporal microscopy is currently the most common method to identify glomerular or non-glomerular hematuria.
3.After localization of hematuria, further diagnosis of the cause of hematuria should be performed
Glomerular hematuria includes: infectious nephritis (including EB, CMV, Mycoplasma pneumoniae, streptococcus, etc.), primary glomerular diseases (including nephritis, nephrotic syndrome, IgA nephropathy, hereditary nephritis, familial thin basement membrane nephropathy, etc.), secondary glomerular diseases (systemic lupus erythematosus, purpura nephritis, hepatitis B-related nephritis, toxic and drug-induced renal damage, metabolic diseases kidney damage, tumors of primary origin in the kidney, etc.). All of the above diseases have appropriate blood tests, and if hereditary nephritis is considered, a family history of hematuria needs to be traced, and hearing and fundus tests are also required. Most patients with hematuria can eventually be diagnosed by renal biopsy.
Non-glomerular hematuria includes infections, idiopathic hypercalciuria, nutcracker syndrome, injuries, tumors, and malformations. Urine culture, urinary calcium, left renal vein ultrasound, and urography are required. In patients who present with only simple hematuria, it is currently believed that pathological examination of the kidney can be dispensed with because of the mild lesions in most patients, but close clinical follow-up should be performed. Hematuria in combination with proteinuria requires aggressive treatment, as proteinuria is an independent risk factor for progressive kidney damage.
Treatment of hematuria
The cause of hematuria is complex and some of the conditions are very serious. You should go to a nephrology specialist as early as possible to confirm the diagnosis, treat it promptly and review it regularly.