Facts you should know about blood in the urine
- Blood in urine can sometimes be visible only with a microscope.
- Evaluating blood in urine requires consideration of the entire urinary tract.
- Tests used for the diagnosis of blood in urine may include a CT scan, cystoscopy, ultrasound, IVP, MRI, urine culture, and urine cytology.
- Management of blood in the urine depends upon the underlying cause.
What is blood in the urine (hematuria)?
Hematuria, or blood in the urine, can be either gross (visible) or microscopic (blood cells only visible through a microscope). Gross hematuria can vary widely in appearance, from light pink to deep red with clots. Although the amount of blood in the urine may be different, the types of conditions that can cause the problem are the same, and require the same kind of workup or evaluation.
People with gross hematuria will visit their doctor with this as a primary complaint. People who have microscopic hematuria, on the other hand, will be unaware of a problem and their condition will most commonly be detected as part of a periodic checkup by a primary-care physician.
What are the causes of blood in the urine?
The causes of gross and microscopic hematuria are similar and may result from bleeding anywhere along the urinary tract. One cannot readily distinguish between blood originating in the kidneys, ureters (the tubes that transport urine from the kidneys to the bladder), bladder, or urethra. Any degree of blood in the urine should be fully evaluated by a physician, even if it resolves spontaneously.
Infection of the urine, (often called a urinary tract infection or UTI) stemming either from the kidneys or bladder, is a common cause of microscopic hematuria. Urine is naturally sterile and should not contain bacteria. Kidney and bladder stones can cause irritation and abrasion of the urinary tract, leading to microscopic or gross hematuria. Trauma affecting any of the components of the urinary tract or the prostate can lead to bloody urine. Hematuria can also be associated with renal (kidney) disease, as well as hematologic disorders involving the body's clotting system. Medications that increase the risk of bleeding, such as aspirin, warfarin (Coumadin), or clopidogrel (Plavix), may also lead to bloody urine. Lastly, cancer anywhere along the urinary tract can present with hematuria.
What tests diagnose the causes of blood in the urine?
The evaluation for blood in urine consists of taking a history, performing a physical examination, evaluating the urine with a chemical test strip and under a microscope, and obtaining a culture of the urine to identify any bacteria present. Lower urinary tract symptoms, such as urgency (feeling a strong need to urinate) and frequency (needing to urinate frequently), as well as burning or pain when urinating, the presence of fever or chills, are suggestive of infection. Recent trauma, even if believed by the patient to have been inconsequential, should be considered as a potential cause. Abdominal or flank pain, especially if radiating to the inguinal or the genital area, may suggest ureteral or kidney stones. All recent medications, including vitamins or herbal supplements, should be reviewed with the health-care professional. However, it is important to note that even if the patient has been taking a medication that is associated with bleeding, a full workup (as listed below) should still be undertaken.
The physical exam will focus on possible sources of hematuria. Bruising over the back or abdomen may indicate trauma. A digital rectal exam should be performed, especially in males, as findings consistent with prostatitis (for example, tenderness on palpation of the prostate) or an enlarged prostate suggestive of benign prostatic hyperplasia (BPH), may be useful in making a diagnosis. The finding of a nodule or an area of induration (hardening) of the prostate may be indicative of cancer. A repeat urinalysis, as well as a urine culture, should be obtained. The presence of white blood cells on urinalysis is more consistent with a urinary tract infection. Protein, glucose, or sediment in the urine may indicate the presence of a disease of the kidneys. Blood tests are also important, as they will aid in assessing renal function and identifying any clotting abnormalities.
In addition to the basic history and physical exam, there are three additional components for any workup of hematuria: imaging, urine cytology, and cystoscopy.
The CT scan is an imaging evaluation of the urinary tract. Prior to the procedure, the patient drinks an oral contrast agent and a dye is injected intravenously. The patient then goes through the CT scan machine and images are taken of the abdomen and pelvis. Another test that can be performed, the intravenous pyelogram (IVP), is also a type of X-ray evaluation of the urinary tract. In this procedure, a dye is injected into the veins, and this is filtered by the urinary tract. A series of X-rays are then taken over a 30-minute period to look for abnormalities. The CT scan is more commonly performed than the IVP to evaluate the urinary tract and should be considered the test of choice. Both of these studies are especially useful for evaluating the kidneys and ureters, but not the bladder, prostate, or urethra. Therefore, a second examination called a cystoscopy is necessary. This is a simple 10-minute procedure using a thin, flexible cystoscope (or fiberoptic camera), which is inserted via the urethra into the bladder to directly visualize any lesions or sources of bleeding. This is usually done with local anesthetic jelly injected into the urethra. Finally, urine cytology involves giving a urine sample to be analyzed by a pathologist for the presence of cancerous or abnormal-appearing cells.
What are the treatments for blood in the urine?
Treatments for hematuria vary widely and depend on the reason for the bleeding. It is important to note that quite often no cause is found for the hematuria. This should not be a source of major concern, however, since an appropriate workup effectively rules out the most serious causes of hematuria (for example, cancer). In cases where a workup is negative and the cause of the hematuria remains unknown, observation with repeat urinalyses is a reasonable option. A blood test to check kidney function and a blood-pressure check should be done as well. Caucasian men over 50 should discuss with their doctor an annual prostate-specific antigen (PSA) blood test which is used to screen for prostate cancer. Prostate screening in African Americans traditionally begins at age 45 and in all races, a history of prostate cancer in close family members may indicate an earlier start of screening.
Further discussion of the treatment for hematuria would depend upon the results of the workup and the exact cause for the hematuria. The urologist who performs this examination is responsible for recommending any further treatment or workup that would be necessary.
Previous contributing author: Mark H. Katz, MD
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