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Blood In The Urine

Blood In The Urine

Alternate Names

  • hematuria
  • Urinary system


Blood in the urine can be visible as an individual urinates, it may be noticed when the urine is tested by a special stick that turns a different color when it reacts with blood, or it may be seen only under a microscope during urinalysis testing.

What is going on in the body?

Not all cases of dark or red urine are due to blood. A protein called myoglobin from muscle breakdown can darken the urine, as can eating a large amount of beets. The antibiotic rifampin turns the urine orange. True blood in the urine can only be confirmed when red blood cells are seen under a microscope. There are many possible causes of blood in the urine, most of them serious.


What are the causes and risks of the condition?

There are many possible causes of blood in the urine, including:
  • bladder and urethra infections or other inflammations (called interstitial cystitis)
  • bleeding or blood-clotting disorders as might be seen in someone taking too much of a blood-thinning medication or with a congenital disease such as hemophilia.
  • kidney injury/inflammation such as that from glomerulonephritis.
  • a kidney stone
  • sickle cell disease, an inherited condition usually seen in African American people. It results in abnormally shaped red blood cells, which can injure the kidney. Patients with sickle cell trait (that is only 1 rather than 2 abnormal genes) can also have blood in the urine.
  • a tumor or cancer in the kidney, the ureters (the tubes that connect the kidney to the bladder), the bladder, or prostate. In children this can be a tumor of the kidney called Wilms' tumor.
  • polycystic kidney disease
  • strenuous exercise
  • some drug reactions (called interstitial nephritis)
Other causes are also possible. Sometimes, no cause can be found.


What can be done to prevent the condition?

Most cases cannot be prevented. Drinking fluids and taking certain medications can prevent kidney stones in some individuals. Some cases of urethritis are caused by sexually transmitted diseases. Some bladder infections can be prevented by timely urination, medications, or cranberry juice.


How is the condition diagnosed?

Diagnosis begins with a medical history and physical exam. The blood in the urine may then be identified by inspection if the urine is red, by a stick placed in the urine that changes color in the presence of blood, and confirmed by a microscopic exam.
Further testing may then be necessary. If pieces of injured tubes and cells from the kidney can be seen in the urine with the microscope, if protein is present in the urine, and if blood tests show impaired kidney function, then the blood in the urine may be due to glomerulonephritis. This inflammation of kidney structures may be confirmed with a biopsy of the kidney.
Special X-ray tests of the kidneys and bladder may also be done. Usually a CT scan is performed if a tumor or kidney stone is suspected to be responsible for the blood in the urine.
A procedure called a cystoscopy may be needed in some cases. A tiny tube with a light and camera on the end is used. This tube can be inserted into the urethra and pushed up into the bladder. The inside of the urinary tract, especially the bladder, can be seen with the camera. This may help a doctor discover the source of bleeding if it is from the bladder.
Blood tests can diagnose sickle cell disease or trait. Urine cultures may be done if an infection is suspected.

Long Term Effects

What are the long-term effects of the condition?

Long-term effects depend on the cause. Serious kidney infections or cancer may result in death. Most infections and kidney stones disappear with treatment and have no long-term effects.

Other Risks

What are the risks to others?

Blood in the urine itself is not contagious. If a sexually transmitted infection is the cause, it may be contagious. Most urinary tract infections are from organisms living in or on a person's own body and are thus not considered contagious.


What are the treatments for the condition?

Treatment is directed at the cause. A person who has a kidney stone is often given lots of fluid and pain medicines, and the stone usually passes on its own. If not, surgery or another procedure such as lithotripsy or endoscopy may be needed to remove the stone. Stones that are captured are sent a lab for analysis. Treatment depends on the type of material making up the stone. A person with an infection may be given antibiotics, while someone with a tumor or prostate enlargement may need surgery, radiation and/or chemotherapy depending on the tumor and its stage.

Side Effects

What are the side effects of the treatments?

Side effects depend on the treatments used. Antibiotics can cause an allergic reaction, stomach upset, or colitis. Pain medicines may cause drowsiness or allergic reactions. Surgery can be complicated by bleeding, infection, or an allergic reaction to the anesthetic.

After Treatment

What happens after treatment for the condition?

Treatment usually cures a person who has an infection or a kidney stone, and the person can resume normal activities. Someone with cancer may die from the cancer if treatment is not successful or the tumor is far advanced..People with sickle cell disease often need close monitoring throughout life. Periodically, sickle cell disease needs to be treated with fluids, medications, and sometimes blood transfusions.


How is the condition monitored?

Urine can be tested with a urinalysis and urine culture until blood is no longer seen. Other monitoring is related to the cause. For example, a person who takes warfarin needs a periodic blood test to check his or her clotting function. Any new or worsening symptoms should be reported to the healthcare professional.


Harrison's Principles of Internal Medicine, 1998, Fauci et al.

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