Blood in the urine, medically termed hematuria, is a symptom requiring professional evaluation. While the sight of discolored urine can be alarming, it indicates a process occurring somewhere within the genitourinary tract, which includes the kidneys, ureters, bladder, and urethra. Hematuria is not a diagnosis itself, but rather a sign that requires investigation to determine the underlying source of bleeding, ranging from benign inflammation to more serious conditions.
The Difference Between Visible and Microscopic Blood
Hematuria is categorized into two types based on detection. Gross, or visible, hematuria is the most obvious form, where the urine appears pink, red, or a dark cola color due to a high concentration of red blood cells. This visible blood often prompts a quicker visit to a healthcare provider and has a higher association with serious conditions, including malignancy.
Microscopic hematuria involves blood amounts too small to change the urine’s color. This form is only discovered during a laboratory analysis, such as a routine urinalysis, which reveals a specific number of red blood cells per high-power field. While microscopic hematuria carries a lower risk of malignancy, it still requires investigation to rule out various underlying conditions.
Causes Originating in the Bladder and Urinary Tract
A common cause of bleeding in the lower urinary system is a urinary tract infection (UTI). UTIs occur when bacteria enter the urethra and travel to the bladder. Although less frequent in men, UTIs cause inflammation and irritation of the bladder lining, leading to blood cells in the urine. Symptoms often include a burning sensation during urination, frequent urge, and cloudy or foul-smelling urine.
Another mechanical cause is the formation of kidney or bladder stones. These solid masses of crystallized minerals cause trauma as they move through the narrow passages or irritate the bladder wall. The stones result in bleeding that can be microscopic or visible, often accompanied by intense, wave-like pain in the back or side.
A more serious concern originating in the bladder is cancer, where the most common presenting sign is often painless gross hematuria. The bleeding can be intermittent, sometimes resolving temporarily, which may cause a delay in seeking medical evaluation. Bladder inflammation, known as cystitis, can also cause hematuria without an infection. Non-infectious irritation can be triggered by radiation therapy or certain medications, causing the delicate bladder lining to bleed.
Prostate Kidney and Systemic Contributors
Prostate Issues
A significant number of hematuria cases in middle-aged and older men are linked to the prostate gland, which sits just below the bladder and surrounds the urethra. Benign Prostatic Hyperplasia (BPH), the non-cancerous enlargement of the prostate, is a frequent contributor. The enlarged gland can increase the vascularity of the surrounding tissue, making it more prone to bleeding, or it can cause congestion of the veins in the bladder neck. Prostate growth also compresses the urethra, leading to difficulty emptying the bladder and subsequent irritation or infection, which further contributes to hematuria. Prostate cancer is a less common cause of hematuria than BPH, but it remains a potential source of bleeding.
Kidney and Trauma
Issues with the kidneys can also be the source of blood in the urine, indicating an upper tract problem. Conditions like glomerulonephritis involve inflammation of the tiny filtering units within the kidney, allowing red blood cells to leak into the urine. Physical trauma to the flank or abdomen, such as from a fall or a sports injury, can also cause a kidney contusion that results in bleeding.
Systemic Factors
Beyond localized issues, certain systemic factors and external influences can cause hematuria. Strenuous or prolonged exercise, particularly long-distance running, can lead to “runner’s hematuria.” This temporary condition is thought to be caused by physical trauma to the bladder or changes in kidney blood flow during intense activity. Furthermore, certain medications, specifically blood thinners like aspirin or warfarin, can increase the risk of bleeding in the urinary tract.
When to Seek Care and What to Expect at the Doctor
Any instance of blood in the urine, whether visible or microscopic, warrants an evaluation by a healthcare professional, typically a urologist or primary care provider. Immediate emergency care is necessary if the bleeding is severe, if you are passing large blood clots, or if you are completely unable to urinate, as this could indicate an obstruction. Do not delay seeking attention even if the bleeding is painless or resolves on its own, as intermittent hematuria can be a sign of a serious underlying issue.
The diagnostic process begins with a detailed medical history and a physical examination, followed by a urinalysis to confirm the presence of red blood cells. A urine culture may also be performed to check for a bacterial infection, which is often treated with antibiotics. If an infection is ruled out, the physician will typically order imaging studies, such as a computed tomography (CT) scan or an ultrasound, to visualize the kidneys and ureters for stones or masses.
For a direct view of the lower urinary tract, a procedure called a cystoscopy may be performed, involving the insertion of a thin, flexible tube with a camera into the urethra and bladder. These combined evaluations are necessary to identify the exact location and nature of the bleeding source. The appropriate treatment, whether it is medication for an infection, a procedure to remove a stone, or intervention for a malignancy, depends entirely on the cause identified through this thorough workup.