What Causes Blood in Urine?

Hematuria is a medical condition characterized by blood in urine. Most cases don’t necessarily indicate a serious disorder, however, seeing blood in urine could be a sign that something’s wrong with your internal organs.

There are two kinds of hematuria, microscopic and gross (or macroscopic). Microscopic hematuria is blood in urine that can only be detected using a microscope. This type of hematuria is not visible to the naked eye. Gross hematuria has noticeable signs such as a weird coloured urine, often in the colours red, brown, or pink. In rare cases, gross hematuria can lead to blood clots and painful or difficult urination.

What are Possible Causes of Blood in Urine?

Several conditions can cause hematuria. There are instances when blood can come from the vagina or bowel movement, however if it’s in urine there might be several potential reasons:

  • Urinary tract infection (UTI) is one of the common causes of hematuria. A healthy urine is sterile and should not contain any form of bacteria or blood cells or protein. A UTI can affect the bladder and/or the kidney. Bladder Infection or acute cystitis is also one of the common causes of painful urination.
  • In children, the commonest cause of blood in urine is kidney inflammation caused by a virus or bacteria. Children with this disease often experience fever and may describe burning pain while urinating.
  • Kidney and bladder stones often cause irritation and abrasion of the urinary tract, which leads to gross hematuria. These stones form from the tiny crystals and minerals contained in your urine. If they become large enough, they can block your urinary tract and cause severe pain as well as bleeding.
  • Kidney injury from trauma can cause hematuria. For example from sport or a car crash or even a simple fall at home.
  • Kidney or renal disease can cause hematuria. The most common kidney disease is glomerulonephritis. This usually causes microscopic hematuria.
  • Men with enlarged prostates can also suffer from hematuria. This is common among men approaching middle age or those that are 50 and older.
  • Sickle cell anemia is a hereditary disorder which affects the hemoglobin in red blood cells and the shape of the red blood cells. The cells can become damaged as they pass through the kidney, resulting in hematuria.
  • Strenuous exercise can also cause urinary bleeding. This is called jogger’s hematuria or jogger’s bladder. Blood can come from the bladder rubbing on itself, or else from the kidneys. This is usually self-limiting and not dangerous.
  • A person with a family history of kidneys stones has a higher risk of hematuria compared to those who don’t. And a higher risk of kidney stones unfortunately!
  • Medications can cause hematuria. Most commonly those medications which thin the blood for example aspirin, warfarin or anti-platelets. If you are taking one of these medicines, you cannot assume there is no other cause however, and still need to advise your doctor.
  • Cancer of the urinary tract can cause hematuria. For example prostate cancer, bladder cancer or kidney cancer.


blood in urine

Treatment depends on the cause of the problem.  Usually, there’s no treatment necessary for hematuria. Hematuria should always be reported though, to rule out something serious. Doctors will ask about your medical history first, before under-going a series of tests.

Blood in the urine is investigated by assessing the urinary tract of an individual. This usually involves a bladder inspection using a telescope, called cystoscopy. The rest of the urinary tract is assessed using imaging tests such as CT scan, ultrasound scan, MRI scan or Intra-venous pyelogram, or IVP.

Urine culture (to check for infection) and urine cytology (to check for cancerous cells)  may also be used to obtain a diagnosis for hematuria.

If blood in urine is caused by an infection, the treatment is generally antibiotic medicine. Other treatments will be based on the final diagnosis.

When Should You See a Doctor?

As soon as you notice blood in your urine, make an appointment with your doctor. Change in urine color can sometimes be caused by foods and medications and might go away within a few days. However, only a doctor can properly diagnose this disease. Ignoring hematuria can lead to serious conditions such as kidney disease and cancer.

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