1. How is hematuria defined medically? Does red urine mean hematuria?
Hematuria is very common in clinical practice, but it is not the case that red urine is hematuria, nor can hematuria be ruled out if the urine is normal in color. The medical definition of hematuria is: ≥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 red blood cell count, all indicate an abnormal increase in red blood cells in urine, which can also be called hematuria. Some hematuria can be seen with the naked eye, while others can only be seen under a microscope. Zhang Zhensheng, Department of Urology, Shanghai Changhai Hospital
However, it is worth noting that red urine does not mean hematuria. When you find “red urine”, you should first distinguish whether it is true or false hematuria. Some drugs can cause red urine, such as the antipyretic drug aminopyrine, the antiepileptic drug phenytoin sodium, the anti-tuberculosis drug rifampin, etc. These should be distinguished from true hematuria.
2.Why is it that some hematuria can be seen with the naked eye, while others can only be seen under a microscope, and what is the difference? Is the hematuria that is visible to the naked eye more serious?
We usually classify hematuria into hematuria with the naked eye and hematuria under the microscope according to whether the color of the urine is red to the naked eye. When the number of red blood cells in urine reaches a certain level, hematuria will be visible to the naked eye, generally more than 1ml of blood per 1000ml of urine will be visible to the naked eye, which we usually call “wash water-like change”. If the amount of bleeding is less than 1ml per liter of urine, then the red blood cells in the urine exceed the standard but cannot be distinguished under the naked eye and can only be found by microscopic examination, then it is called microscopic hematuria.
The severity of hematuria and whether it is visible to the naked eye are not necessarily related to the severity of the disease, some very serious hematuria may be caused by benign problems such as stones, inflammation or congenital malformations; while some microscopic hematuria is likely to be caused by tumors with a high degree of malignancy.
3.What are the causes of hematuria? Why is it sometimes impossible to find out the cause of hematuria?
The causes of hematuria are many and complex, and both local and systemic diseases can cause hematuria. In terms of general classification, there are three main types of hematuria.
First, the genitourinary system itself, the kidney, ureter, bladder, prostate, urethra and other parts of the inflammatory infection, long stones, tumors, trauma, or congenital malformations, will appear hematuria, such as acute and chronic glomerulonephritis, acute cystitis, urinary tuberculosis and other inflammatory infectious diseases; kidney, ureter, bladder and other parts of the stone movement will cut through the urethral epithelium and thus Hematuria can also be caused by malignant tumors invading normal tissues in any part of the urinary system; hematuria can also occur if the kidneys and bladder are violently injured in traffic accidents; there are also genetic diseases or malformations such as polycystic kidney and nutcracker syndrome phenomenon (the disease is a congenital malformation of blood vessels, in which the left renal vein is extruded between the abdominal aorta and the superior mesenteric artery, causing intractable microscopic hematuria or even carnal hematuria). present with hematuria.
The second major category is systemic diseases, which is well understood, such as thrombocytopenic purpura, hemophilia, leukemia, and other systemic hemorrhagic diseases that easily involve the urinary system; some rheumatic immune diseases, such as systemic lupus erythematosus, dermatomyositis, and scleroderma, often involve the kidneys and cause microscopic hematuria or even sarcoid hematuria; some allergies, drugs, and toxins that cause systemic reactions will also manifest in the urinary system and appear Hematuria.
The third major category is the lesions of the organs adjacent to the genitourinary system: this is a “fire in the city and a fish in the pond”, such as tumors of the uterus, vagina or rectum that invade the urinary tract can also cause severe hematuria.
Another condition is that hematuria can occur in physiological situations, such as microscopic hematuria after strenuous exercise, but this is a transient condition that will disappear after adequate rest and rechecking.
However, about 10% of patients with hematuria are unable to identify the site and cause of the disease after various detailed examinations, which is called “idiopathic hematuria”. Some patients with idiopathic hematuria cannot be detected in the early stage of the disease, but the cause of the disease will be found through long-term close follow-up, and some of them are not caused by systemic or local pathological changes. Therefore, patients with idiopathic hematuria should neither worry nor take it lightly, and should be reviewed and followed up regularly.
4, hematuria is sometimes very simple and nothing is felt, while sometimes it is accompanied by other symptoms, such as urinary frequency and urgency, painful urination, and difficulty in urination, etc. Is it that it does not matter if there are no other accompanying symptoms?
Hematuria can be a simple symptom, or it can be accompanied by other symptoms. However, the presence or absence of concomitant symptoms is not necessarily related to the severity of the disease, and to some extent, hematuria without concomitant symptoms even deserves more attention. For example, we often say to patients in layman’s terms that “hematuria is not painful, but painless”. Because “intermittent painless hematuria” is a very important feature and signal of urological tumor.
For example, sudden hematuria with frequent, urgent and painful urination is often a urinary tract infection; sudden hematuria with back pain is often a kidney stone or ureteral stone attack; a patient with a history of prostate enlargement and long-term difficulty in urination may have hematuria caused by the rupture of the dilated blood vessels on the surface of the prostate.
5.Do I have to go to the hospital for relevant tests when I have hematuria? What tests are generally available to find the cause of hematuria?
As I mentioned in the previous question, whenever hematuria occurs, it must be taken very seriously, whether it is visual or microscopic hematuria; whether it is simple hematuria or hematuria with accompanying symptoms, it is important to go to the hospital in a timely manner.
Generally speaking, patients with hematuria should go through the following tests to clarify the cause step by step: urinary routine, urine phase analysis and urinary ultrasound are the first-line tests: urinary routine can perform qualitative and quantitative tests on hematuria; urine phase analysis can determine whether it is medical hematuria (such as nephritis) or surgical hematuria (such as tumors and stones) by the proportion of abnormal red blood cells in the urine; urinary ultrasound can perform preliminary tests on the presence of tumors and stones in the urinary system. Tumors and stones can be screened initially, and it also helps to understand whether the prostate is enlarged and whether there is a blood clot in the bladder.
If the percentage of abnormal red blood cells in the urine is relatively high, the main consideration is medical hematuria, and you should visit the nephrology department to investigate the cause. If this percentage is less than 10%, surgical hematuria is considered. Next, we should do: hematocrit, urine exfoliated cells, intravenous pyelogram (normal renal function), these tests help to determine the presence of tuberculosis, tumor, stones and other diseases, and if vascular malformation is suspected, renal vein ultrasound can be done. If imaging suggests neoplastic bladder, further cystoscopy is done. Some more specific diseases require special tests such as magnetic resonance and retrograde urography to assist in identification and judgment.
In short, the examination of hematuria follows the principles of simple to complex, non-invasive to invasive, both qualitative and localized to carry out.
6.Does all hematuria need treatment?
This topic is rather general. In terms of science and rationality, the treatment of any disease must be based on a clear diagnosis, so that the treatment can be targeted. However, in clinical work, we can also refer to the principle and idea of simultaneous treatment of the cause and symptom.
If the patient has obvious hematuria or even a rapid drop in hematocrit, it is necessary to actively treat the hematuria with hemostasis or even blood transfusion to bring it under control and further investigate the cause after the condition has stabilized. Of course, some hematuria can only be solved by timely surgical intervention, such as arterial bleeding on the surface of the bladder or prostate, which can only be solved by timely and decisive surgery while maintaining stable vital signs.
But clinically the vast majority of patients’ hematuria is not so serious, mostly transient, or light red, at this time should focus on the investigation of the cause, and at the same time can drink more water, oral hemostatic drugs symptomatic treatment. Wait until the cause is clear before doing further more targeted treatment.
7.What do patients with hematuria need to pay attention to in their daily life?
The daily life precautions for patients with hematuria cannot be generalized, but should be individualized according to the cause of the disease. For example, water intake should be limited for hematuria caused by glomerulonephritis, but increased water intake is needed for hematuria caused by small stones. This example shows that it is important to investigate the cause of hematuria so that we can “see what we eat”, prescribe the right medication and guide the follow-up precautions. Patients who have no detectable cause of hematuria, i.e. “idiopathic hematuria”, should also be followed up regularly (every 3-6 months) at the hospital.
8.Addendum: One of the most important causes of hematuria: urological tumors (bladder cancer)
As already mentioned, there are very many causes of hematuria, but I would like to emphasize urinary tumors in particular. This is because the consequences of misdiagnosis and omission of urinary tumors are very serious compared to those caused by benign diseases such as inflammation and stones. In my clinical practice, I often encounter patients with advanced bladder tumors, and when I review their medical history, the first time these patients develop hematuria is often a year or even a few years before they are diagnosed, and we all know that early diagnosis and timely treatment are necessary to overcome tumors.
The initial manifestation of bladder cancer, ureteral cancer and kidney cancer can be painless hematuria, especially bladder cancer is the most common. The characteristic of hematuria caused by bladder cancer is “intermittent painless hematuria”, i.e. hematuria is sometimes absent, sometimes more and sometimes less, it can last for several days or not appear for a long time, and it can be either visual or microscopic hematuria. The reason why painless carnal hematuria is so dangerous is that patients with this type of hematuria do not have any symptoms and the hematuria often disappears on its own without treatment, so patients are often confused by its illusion and delay the diagnosis. In fact, these illusions are exactly the danger signs of urinary tumors, and when the hematuria worsens, the tumor is often already at an advanced stage. Of course, it should be clarified here that listeners should not fall into two misunderstandings: firstly, the phrase “hematuria is not painful, but painless” does not apply to all patients, because not all hematuria caused by urological tumors is painless, but can also be accompanied by lumbar and abdominal pain and irritating symptoms such as urinary frequency, urinary urgency and pain. Secondly, we should not just think that carnal hematuria indicates a serious condition and must be diagnosed and treated urgently, but think that microscopic hematuria is not important. This misconception may lead to serious consequences. The severity of urological tumors and the severity of hematuria are not proportional, and many tumors often only present as painless microscopic hematuria.
In conclusion, painless hematuria is an important early sign of urological tumor, especially bladder tumor, especially for middle-aged and elderly men with smoking history, which should not be ignored. Once painless hematuria is found, regardless of whether it is carnal or microscopic hematuria, you should go to hospital for examination and confirmation.