In everyday life, if you find that your urine appears red, you should be alerted. The urine of healthy people usually contains no or occasional traces of red blood cells, but if certain diseases occur, they can cause an abnormal increase of red blood cells in the urine, which is clinically called “hematuria”. If the urine is normal in color and only red blood cells can be seen under the microscope, it is called “microscopic hematuria”; if the urine contains a large number of red blood cells and is blood-red in color, it is called “visual hematuria”. Both microscopic hematuria and visual hematuria should be taken seriously, but the presence of visual hematuria may be more serious. In a small number of patients, the sudden onset of botrythematous hematuria without any obvious cause, but without other manifestations such as pain, is clinically known as “painless botrythematuria”. It is usually regarded as an important warning sign of urological tumor and should be paid special attention. Especially in elderly people, the cause should be promptly identified at the hospital. What are the common causes of painless botrythematuria? There are many causes of sarcoid hematuria, but about 95% of them are due to diseases of the urinary system itself, with various urinary tract infections, urinary stones, urinary tract tumors (kidney, ureter, bladder, prostate tumors, etc.), renal cystic diseases (polycystic kidney, renal cyst), benign prostatic hyperplasia, and glomerulonephritis (IgA nephropathy) being the most common. IgA nephropathy is mainly seen in children and adolescents. Painless hematuria in the elderly is usually seen in patients with urological tumors: epithelial tumors of the urinary tract (bladder tumors, kidney and ureteral tumors, etc.) are more common in patients between 40 and 60 years of age, and in patients over 60 years of age, in addition to epithelial tumors of the urinary tract, prostate cancer and benign prostatic hyperplasia are also seen. The hematuria caused by uroepithelial tumors is often intermittent, and sometimes it can disappear without treatment once it appears, so it is easy to be ignored and thus delay the diagnosis and treatment. The actual hematuria of the elderly is painless, even if it is only once, you should go to the hospital for further examination. In a few patients with prostate enlargement, the enlarged prostate gland protrudes into the bladder, causing congestion and rupture of the submucosal blood vessels in the bladder neck, resulting in hematuria and sometimes blood clots. These patients often first experience symptoms such as frequent urination, increased urination at night (more than 2 times), and progressive difficulty in urination early on. In addition, systemic bleeding disorders (such as hemophilia, aplastic anemia, idiopathic thrombocytopenic purpura, etc.) and physicochemical factors (such as food allergy, radiation exposure treatment, drugs, toxins, strenuous exercise, etc.) can also cause different degrees of granulomatous hematuria. Of course, not all painless sarcoid hematuria is caused by tumors. After finding red urine, you should not panic and firstly distinguish whether it is real or pseudo hematuria. Some drugs can cause red urine, such as aminoglycoside antibiotics (including gentamicin, kanamycin, tobramycin, etc.) and sulfonamides (such as cotrimoxazole, etc.) can cause nephrotoxic damage and hematuria. Cephalosporins can be more nephrotoxic if combined with aminoglycosides or diuretics. Other drugs such as aspirin and cold pass can also sometimes cause hematuria. Second, what tests should patients with painless hematuria have? The initial doctor will take a detailed history of the patient and determine the appropriate tests based on the patient’s description of the hematuria symptoms and the severity of the hematuria. Routine urinalysis and genitourinary ultrasound are the necessary preliminary tests. 1. Routine urine examination: It can find out whether there are red blood cells in the urine to indicate whether it is hematuria or hemoglobinuria; the presence of white blood cells in the urine can indicate whether there is urinary tract infection. The presence of tubular pattern in the urine sediment, especially the red blood cell tubular pattern, indicates that the bleeding comes from the renal parenchyma and is highly suggestive of glomerulonephritis. If a large number of deformed red blood cells (more than 80%) are present in the urine, this is often indicative of glomerular hematuria. If the deformed red blood cells in the urine are less than 20%, it is often indicated as non-glomerular hematuria. If the number of deformed red blood cells and normal red blood cells in the urine is basically equal, it often indicates glomerular damage combined with urinary tract lesions below the glomerular site. Imaging: Urological ultrasound, abdominal plain film, retrograde urography, intravenous urography and CT examination can help identify the cause of non-glomerular hematuria, and can detect tumors, cysts, stones and enlarged prostate of the urinary system. 3. Cystoscopy and ureterorenoscopy: They can help to understand the urinary tract pathology of patients with sarcoid hematuria that cannot be identified by the above methods, and they can also take biopsies or perform the necessary treatment at the same time. In conclusion, painless hematuria in the elderly should be taken seriously enough, seek medical attention early and actively search for the cause with the help of doctors so that early diagnosis and early treatment can be achieved.