Chemotherapy is a fundamental treatment for many cancers, eliminating cancer cells throughout the body. While these powerful medications target rapidly dividing cells, they can also affect healthy cells, leading to various side effects. One potential side effect is blood in the urine, known as hematuria. Understanding its causes and management is important for navigating cancer treatment.
Understanding Blood in Urine During Chemotherapy
Chemotherapy can cause blood in the urine, a condition called hematuria, where red blood cells are present. Hematuria manifests in two primary ways: microscopic or gross. Microscopic hematuria is not visible to the naked eye and is typically detected during laboratory urine tests. Gross hematuria is visible, causing the urine to appear pink, red, or brown, and sometimes includes blood clots.
The occurrence and severity of hematuria vary significantly among individuals. Factors like specific chemotherapy drugs, dosage, treatment duration, and a patient’s overall health influence its development. While visible blood can be alarming, it is a recognized potential complication.
Mechanisms and Specific Chemotherapy Drugs
Chemotherapy can lead to hematuria through several mechanisms affecting the urinary system. One primary cause is direct bladder toxicity, often resulting in hemorrhagic cystitis. Certain oxazaphosphorine agents like cyclophosphamide and ifosfamide are metabolized into substances that irritate and damage the bladder lining. Acrolein, a key breakdown product, accumulates in the bladder, causing inflammation, ulceration, and bleeding. Hemorrhagic cystitis can develop during treatment, immediately after, or even months later.
Beyond direct bladder irritation, some chemotherapy agents can affect the kidneys, potentially contributing to hematuria. Less common, platinum-based drugs like carboplatin have been associated with kidney issues, including hematuria. Damage to kidney cells or structures can lead to bleeding that passes into the urine.
Another mechanism is bone marrow suppression, a common side effect of many chemotherapy regimens. Chemotherapy can reduce the production of platelets, which are essential for blood clotting. A low platelet count (thrombocytopenia) increases the risk of bleeding throughout the body, including the urinary tract. This can manifest as blood in the urine, even without direct bladder or kidney damage.
When to Seek Medical Attention for Hematuria
Promptly notify the healthcare team upon observing any blood in the urine during or after chemotherapy, whether slightly pink or overtly red. Any visible blood warrants immediate medical attention to assess the cause and prevent complications.
Reporting this symptom allows the medical team to rule out other causes, such as urinary tract infections, kidney stones, or tumor progression, which can also cause hematuria. The healthcare provider will ask about the color and amount of blood, frequency, presence of blood clots, and any accompanying symptoms like pain, fever, or difficulty urinating. Diagnostic steps include urine tests to confirm red blood cells and identify infections, as well as imaging studies of the urinary tract. Early assessment helps determine severity and guides appropriate management.
Proactive Measures and Treatment Approaches
Preventive strategies reduce the risk of chemotherapy-induced hematuria, especially with drugs known to cause bladder toxicity. Aggressive hydration, through drinking large amounts of fluids or receiving intravenous fluids, flushes toxic metabolites from the bladder, diluting them and minimizing contact time. Frequent urination is also encouraged.
For certain chemotherapy agents like cyclophosphamide and ifosfamide, a uroprotective agent called Mesna is routinely administered. Mesna binds to and neutralizes acrolein, the harmful metabolite responsible for bladder irritation, preventing bladder lining damage without affecting chemotherapy’s anti-cancer activity.
When hematuria occurs, treatment focuses on managing bleeding and its underlying cause. Continued hydration helps clear the bladder. If blood clots obstruct urine flow, bladder irrigation (flushing with a sterile solution) may remove clots and maintain catheter patency. For low platelet counts, platelet transfusions may be necessary. Other medications control bleeding, and in rare, severe instances, more invasive procedures might be considered.