The presence of blood clots in a man’s urine, known as gross hematuria with clotting, is an alarming symptom requiring immediate medical attention. This signifies substantial bleeding within the urinary tract, which includes the kidneys, ureters, bladder, and urethra. While causes range from infections to serious diseases, the clots themselves can be dangerous. Their size and volume can obstruct urine flow, leading to an acute inability to urinate, which is a urological emergency. A prompt and thorough medical evaluation is necessary to identify the source and severity of the bleeding, especially given the wide spectrum of possible diagnoses, including malignancies.
Why Blood Clots Form in Urine
Blood clots form when the volume of blood loss is significant enough for the body’s natural coagulation cascade to activate within the urinary system. This process involves platelets and fibrin working together to seal the bleeding site, creating the jelly-like or stringy masses passed during urination. Clots are a direct indicator that the blood is visible to the naked eye.
The location of the bleeding can sometimes be suggested by the clot’s appearance. Long, stringy, or “worm-like” clots often indicate bleeding originating in the upper urinary tract, such as the kidney or ureter. Since these structures are narrow, the blood coagulates as it travels, molding the clot into a thin, elongated shape. Conversely, larger, more amorphous clots usually suggest bleeding within the bladder. This occurs because there is more space for the blood to accumulate and clot before being expelled. Bleeding that is rapid and continuous is more likely to result in clot formation compared to slow, persistent bleeding.
Common Non-Malignant Sources of Bleeding
Many causes of blood clots in the urine, while serious, do not involve cancer. One common source is benign prostatic hyperplasia (BPH), or an enlarged prostate, which affects many men as they age. The enlarged gland contains numerous fragile, dilated blood vessels that can rupture easily, leading to significant bleeding and clot formation. This bleeding often occurs without any pain and is particularly common in men over 50.
Infections of the urinary tract, especially those that have progressed to affect the prostate (prostatitis) or the kidneys (pyelonephritis), are also frequent causes. The inflammation and irritation of the delicate lining of the urinary tract and prostate can cause blood vessels to leak. While urinary tract infections (UTIs) are more common in women, men with prostate issues have an increased risk, and the resulting inflammation can lead to visible blood and clots.
Kidney and bladder stones, collectively known as urolithiasis, can cause bleeding and clot formation as they move or scrape against the inner walls of the urinary tract. These hard mineral deposits irritate the lining, causing noticeable blood in the urine, often accompanied by severe, cramping pain in the back or flank. Strenuous physical activity, such as long-distance running, can also temporarily cause gross hematuria due to minor trauma to the bladder walls, known as exercise-induced hematuria.
Serious Conditions Requiring Urgent Attention
When blood clots are present, the most serious concern for the evaluating physician is the possibility of a genitourinary malignancy. Bladder cancer is the most frequent cancer associated with gross hematuria and is particularly concerning when the bleeding is painless. The blood comes from the abnormal, fragile blood vessels that supply the tumor, and the presence of clots indicates a substantial tumor burden or active bleeding.
Kidney cancer, specifically renal cell carcinoma, is another malignancy that can cause blood clots in the urine, though it is less common than bladder cancer. Bleeding from a kidney tumor may present with long, thin clots that take the shape of the ureter as they pass down to the bladder. While less frequent, prostate cancer can also be a source of bleeding, though visible hematuria is more often a symptom of advanced disease or is related to other conditions like BPH.
Acute, severe trauma, such as a high-impact injury to the abdomen or flank, can lead to a urinary tract rupture or significant kidney damage. This type of injury can cause massive, rapid bleeding that results in large clots and requires immediate emergency intervention. Additionally, certain rare kidney diseases, like some forms of glomerulonephritis, can lead to substantial blood loss, though this is more commonly associated with microscopic hematuria.
The Medical Assessment Process
A man who passes blood clots must seek immediate medical care, especially if the clots are large enough to cause urinary retention—the inability to pass urine. The initial assessment focuses on stabilizing the patient and relieving any obstruction, often requiring the temporary insertion of a specialized catheter to drain the bladder and flush out the clots.
The full diagnostic workup begins with a detailed medical history and a physical examination, including a digital rectal exam to assess the prostate. Laboratory tests include a urinalysis to confirm the presence of blood and check for infection, as well as blood tests to evaluate kidney function and check for anemia.
Imaging studies are necessary to visualize the entire urinary tract, with a CT urogram being the standard procedure. This specialized CT scan uses intravenous contrast dye to highlight the kidneys, ureters, and bladder, helping to identify stones, tumors, or other structural abnormalities. Following imaging, a cystoscopy is performed. This involves inserting a thin, flexible tube with a camera through the urethra into the bladder, allowing for a direct visual inspection of the bladder lining and the prostate.