The presence of blood in urine, medically known as hematuria, is a warning sign that requires careful attention. While it does not always indicate a serious condition, this symptom should not be ignored. Specialists distinguish between two types of hematuria: macroscopic, when blood is visible to the naked eye, and microscopic, which can only be detected through laboratory analysis. The approach to diagnosis and treatment differs in each case.
According to experts such as Dr. Carlos Núñez, head of urologic surgery at MD Anderson Cancer Center Madrid, the causes of blood in the urine can be varied. Microhematuria is often not linked to severe illnesses. For example, in women, it can be caused by menstrual blood entering the urine. Additionally, for a small percentage of the population (less than 5%), the presence of red blood cells in urine is considered normal. Sometimes, certain foods like beets or medications can change the urine’s color, which may be mistaken for hematuria.
However, blood in the urine may also indicate more serious issues. Among the most common causes are urinary tract infections, the presence of kidney or bladder stones (lithiasis), as well as benign prostatic enlargement in men. Additionally, hematuria can be a symptom of kidney cysts or trauma. The greatest concern is the possibility of tumors in the urinary system, which is why this symptom requires mandatory evaluation.
In some cases, hematuria is not related to urological problems, but to systemic diseases affecting the renal glomeruli. These conditions include diabetes mellitus, arterial hypertension, and lupus. In such cases, patients need to be monitored by a nephrologist to manage the underlying disease.
As people age, many begin taking anticoagulants—blood-thinning medications. These can increase bleeding risk, but it’s important to note that they rarely cause hematuria on their own. Most often, anticoagulants simply exacerbate bleeding from an already existing source, such as an enlarged prostate. Therefore, even when taking these medications, a comprehensive examination is necessary to identify the underlying problem.
The urgency of seeing a doctor depends on the type of hematuria. Microscopic hematuria detected incidentally usually does not require immediate action, but warrants a scheduled visit to a specialist. However, macroscopic hematuria is a serious reason for urgent consultation, especially if it is accompanied by lower back pain, nausea, fever, or persists for a long time.
Diagnosis begins with the least invasive methods. The doctor orders urine tests, urine culture, cytological examination to detect atypical cells, and imaging studies such as ultrasound, CT scan, or MRI. If these methods do not provide a clear diagnosis, cystoscopy — an endoscopic examination of the bladder — may be required.
Hematuria can also be accompanied by other symptoms: lower back pain, burning during urination, and frequent urges to urinate. However, asymptomatic hematuria is considered particularly dangerous, especially in smokers, as it may be the only early sign of cancer. Prevention involves treating chronic diseases, quitting smoking, maintaining adequate hydration to prevent stone formation, and controlling blood pressure.
