Seeing blood in your urine can be frightening, even for the most macho of men. When this occurs, or when your doctor tells you that your urine test showed red blood cells, it's time for a medical evaluation. Although the results are often reassuring, blood in the urine — called hematuria — is a warning sign that you should never ignore.
Types of Urinary Bleeding
If your urine looks pink or red, it's called visible hematuria. Your urine can look normal but still have red blood cells in it. This is called invisible or microscopic hematuria. It is usually detected during a routine urine analysis.
Hematuria may or may not have symptoms. Here are some symptoms that suggest particular causes of hematuria:
- Urinary burning and frequent urination, with or without fever, suggest an infection in the prostate, bladder or kidney.
- Severe crampy pain over the kidney or abdomen suggests a kidney stone.
- Weakness, weight loss, fatigue, joint pain, or fatigue could be signs of an illness (such as vasculitis or infection) that involves tissues outside the urinary tract.
- A recent accident or blow to the abdomen or back may point to trauma as the cause of urinary bleeding.
Although it's important to look for these clues, they're usually missing. Most hematuria is invisible and has no symptoms.
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Causes of Urinary Bleeding in Men
Major causes of urinary bleeding in men include:
- Kidney disease (IgA nephropathy, hereditary kidney disease, and others)
- Infections of the prostate, bladder or kidney
- Kidney stone disease
- Benign prostate hyperplasia (BPH)
- Cancer of the kidney, ureter, bladder or prostate
- Vigorous exercise ("runner's hematuria")
- Metabolic abnormalities (high calcium or uric acid)
- Narrowing of the ureter that causes back-up of urine in the kidney (hydronephrosis)
- Abnormalities of the kidney's arteries or veins
- Multiple kidney cysts (polycystic kidney disease)
- Radiation damage
- Medication (excessive anti-clotting drugs)
- Sickle cell anemia
A Surprisingly Common Cause of Urinary Bleeding
Vigorous exercise can cause either visible or microscopic hematuria. Running is the classic example. In fact, the problem is often called "runner's hematuria" or "10,000 meter hematuria" after the 6.2 mile (10,000 meter) road races that sometimes trigger it. But other forms of strenuous exercise, ranging from tennis to soccer, can also trigger urinary bleeding.
People with exercise-induced hematuria feel fine. Bleeding occurs in the first few hours after exercise but it goes away quickly, leaving the urine normal within 48 to 72 hours.
If a young man develops urinary bleeding shortly after strenuous exercise, his doctor may decide to simply re-check the urine a few days later and defer further treatment if the urine is normal.
But because urinary tract malignancies can also bleed intermittently, it may be wise to perform a full set of tests in certain men — those over age 50, smokers, those with certain industrial exposures — even if the bleeding is triggered by exercise.
Doctors don't know exactly what causes exercise-induced urinary bleeding. Bladder irritation is a leading possibility. The problem is different from bleeding due to blunt trauma, which may occur in contact sports or accidents.
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Because microscopic hematuria is usually discovered during a routine urine test, it's a good idea to re-test the urine. If two or more tests show red blood cells, it's time to do a more in-depth study of the kidneys.
The first step is to take a closer look at the urine itself. If the urine has even small amounts of protein (microalbuminuria), or if the appearance of the urine cells suggests they come from the kidney's glomeruli (the tiny blood vessels that filter fluid from the blood), the doctor should focus on the possibility of kidney disease. This means first measuring levels of creatinine — a waste product in the blood — to look at kidney function.
Other tests for kidney disease may include blood tests for inflammation, ultrasound imaging to measure kidney size and 24-hour urine collections. The doctor may also check for various causes of kidney disease that don't cause bleeding, such as diabetes and hypertension. Depending on the results, the doctor may recommend seeing a kidney specialist, who may recommend a kidney biopsy. Although some people with this type of microscopic hematuria turn out to have serious kidney disease, most have mild problems, such as IgA nephropathy (deposits of an immune protein on the glomeruli).
You'll probably breathe a sigh of relief if your doctor reports that you don't have kidney disease. But that still leaves you without a diagnosis. This usually means that you'll need more tests to check for other causes of your hematuria.
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If you see blood in your urine, it won't be hard to convince you to have tests to find out why you are bleeding. Among other things, you'll want to be sure you don't have a tumor somewhere in your urinary tract. It's a legitimate concern, particularly for smokers and people over age 50. (A study of 948 patients with visible hematuria found that nearly a quarter had urinary tract malignancies.)
But other conditions may be responsible. (See Causes of Urinary Bleeding in Men.) and thorough testing may not pinpoint the cause in 53% of patients with visible hematuria and in 68% of patients with microscopic hematuria. Still, all patients with blood in the urine need careful evaluation.
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Getting the Right Evaluation
Your doctor will tailor your testing to your personal and family history, your risk factors and your symptoms. Here is a list of tests that may be helpful:
- Physical examination – Your doctor will feel your abdomen for an enlarged kidney or bladder, tap over your kidneys to see if they are tender, and check your prostate with a digital rectal exam.
- Urine tests –In addition to checking for blood, urine tests for protein and cultures for urinary tract infections can be helpful. Patients with risk factors (exposure to tuberculosis, travel, HIV) may be tested for urinary tract tuberculosis.
- Blood tests – Common tests include creatinine and blood urea nitrogen to monitor kidney function, measurements of calcium and uric acid to check for stone disease, and a prostate specific antigen (PSA) test for benign prostatic hyperplasia and prostate cancer.
- Imaging tests – A helical computed tomography (CT) scan, also called a spiral CT, is now the standard type of scan for the urinary tract and many other parts of the body. It's the best test to check for kidney stones, tumors, cysts and blockages. If stones are highly likely, contrast agents should be used to improve the sensitivity of the CT. Ultrasound is a simple alternative for some patients, and MRIs may also be valuable.
- Cystoscopy – If less invasive tests fail to find the cause of hematuria, a urologist may inspect the bladder lining by inserting a fiber-optic scope through the urethra. In most cases, cystoscopy is done in the doctor's office with local anesthesia.
- Urine cytology – Pathologists can perform special microscopic evaluations of urine to look for cancer cells. This is called cytology. It is a less invasive but less sensitive way to check for bladder cancer. Although cytology may help, the American Urological Association recommends cystoscopy for all patients with hematuria over age 40 and for younger patients with risk factors for bladder cancer.
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Putting it in Perspective
Both men and women can experience urinary bleeding. But the problem is more common in men.
Although urinary tract infections can cause hematuria — and are more common in women — many of the other leading causes of urinary bleeding are more common in men: kidney stones, bladder cancer and kidney cancer. (Prostate disease is obviously confined to men.)
Men have a tendency to ignore symptoms (the “Ostrich Syndrome”) or to grit their teeth and try to tough out problems (the “John Wayne Syndrome”). In the case of urinary bleeding, though, ignorance may be blissful in the short run but it's hazardous in the long run.
It's true that many cases of hematuria are never diagnosed, and many others are caused by non-cancer conditions such as infections, kidney stones, BPH and even exercise. But since bladder cancer, kidney cancer and prostate cancer are also on the list of possible causes, every man with blood in the urine, whether it's visible or not, should see his doctor for a thorough evaluation. It's the manly thing to do.
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The Bottom Line
Blood in the urine always requires a complete medical and urological evaluation. But often that evaluation fails to pinpoint the cause. What then? Most people remain well, but some don't. So while vigilance is in order and a periodic urinalysis may be helpful, it's probably not necessary to repeat the full battery of tests unless bleeding recurs or other problems develop.
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Harvey B. Simon, M.D. is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.