Blood clots appearing in the bladder are a sign of gross hematuria, which is visible blood in the urine, and this symptom should always be taken seriously. Hematuria is common, but the presence of clots indicates significant bleeding somewhere within the urinary tract, including the kidneys, ureters, bladder, or urethra. Clots form when platelets and fibrin work together to stop the bleeding source, a normal bodily process. However, when clots form inside the bladder, they can create an immediate physical blockage that requires urgent medical attention.
Why Clots in the Bladder Pose an Immediate Risk
The primary danger posed by blood clots in the bladder is acute urinary retention, often called clot retention. This occurs when clots become large or numerous enough to physically obstruct the bladder neck or the urethra. When this blockage happens, the patient is suddenly unable to urinate, leading to severe lower abdominal pain and bladder distention.
The inability to pass urine constitutes a urological emergency because accumulating pressure can cause significant distress. If the obstruction is not relieved promptly, the resulting back pressure affects the upper urinary tract, causing swelling and damage to the kidneys. This obstruction can lead to a rapid decline in kidney function.
The presence of clots also signals a significant volume of acute blood loss. In severe cases of ongoing bleeding, rapid clot formation can lead to anemia, potentially requiring a blood transfusion. The physical presence of a large clot mass in the bladder is sometimes referred to as bladder tamponade, and in rare instances, extreme pressure has been associated with bladder rupture.
Common Causes of Bladder Bleeding
The formation of bladder clots is a consequence of underlying bleeding, and the source can range from benign conditions to serious illnesses requiring immediate investigation.
One common cause is infection, particularly severe urinary tract infections (UTIs) or cystitis, where inflammation of the bladder lining leads to the rupture of small blood vessels. In hemorrhagic cystitis, the inflammation is pronounced, causing significant bleeding and clot formation.
Physical irritation within the urinary system is another frequent cause, such as kidney stones or bladder stones. As these hard mineral deposits pass through or sit in the urinary tract, they rub against the lining, causing trauma and subsequent bleeding. Trauma from an external injury to the abdomen or pelvis, or internal trauma from recent urological procedures like catheter insertion or surgery, can also result in gross hematuria and clots.
More concerning causes include urological malignancies, which are cancers of the urinary tract. Bladder cancer is the most common tumor causing visible blood in the urine, but bleeding can also originate from kidney or prostate cancer. For individuals over 35, especially those with risk factors like smoking, hematuria requires a thorough workup to rule out a tumor.
Finally, certain medical treatments and conditions contribute to bleeding. Some chemotherapy agents or pelvic radiation can cause inflammation and bleeding in the bladder, a form of hemorrhagic cystitis. While blood-thinning medications like anticoagulants do not typically cause hematuria on their own, they can significantly worsen bleeding from any underlying source, leading to rapid clot accumulation.
Diagnosis and Medical Management
When a patient presents with bladder clots and urinary retention, the medical priority is to immediately relieve the obstruction and stabilize the patient. This typically involves inserting a large-bore urinary catheter, often a three-way catheter, designed to allow for the simultaneous drainage of urine and the introduction of flushing fluids. Manual bladder irrigation or washout is then performed using sterile saline or water, where a syringe is used to instill fluid into the bladder and aspirate it back out to mechanically break up and remove the clots.
For large or tenacious clots that cannot be removed by simple irrigation, urologists may use a cystoscope. This is a thin, lighted tube inserted through the urethra into the bladder, allowing the physician to visualize the lining and use suction or specialized instruments to evacuate the remaining clot material. Once the bladder is clear, continuous bladder irrigation (CBI) may be started. This flushes the bladder continuously to prevent new clots from forming while the active bleeding subsides.
After the immediate crisis of clot retention is managed, the focus shifts to diagnostic investigation to pinpoint the source of the bleeding. Initial steps include a urine analysis to check for signs of infection or abnormal cells, alongside blood tests. Imaging studies, such as a computed tomography (CT) scan or ultrasound, are used to visualize the kidneys and ureters to identify stones or tumors. A formal cystoscopy is also routinely performed to directly examine the lining of the urethra and bladder for lesions, tumors, or areas of active bleeding.