Hematuria is the presence of red blood cells in the urine. If there are enough red cells, the urine can become bright red, pink or cola coloured. Often, however, the urine appears completely normal because there is not enough blood to cause a colour change. In this case, the condition is called “microscopic” hematuria.

There are many possible causes of hematuria, including:

  • Urinary tract infection — Hematuria can be caused by an infection in any part of the urinary tract, most commonly the bladder (cystitis) or the kidney (pyelonephritis).
  • Kidney stones
  • Tumours in the kidney or bladder
  • Exercise — Exercise hematuria is a harmless condition that produces blood in the urine after strenuous exercise. It is more common in males than females.
  • Trauma — Traumatic injury to any part of the urinary tract — from the kidneys to the urethral opening (the connection between the bladder and the outside world) — can cause hematuria.
  • Drugs — Hematuria can be caused by medications, such as blood thinners, including heparin, warfarin (Coumadin) or aspirin-type medications, penicillin, sulpha-containing drugs and cyclophosphamide (Cytoxan).
  • Glomerulonephritis — Glomerulonephritis is a family of illnesses that are characterized by inflammation of the glomeruli, the filtering units of the kidneys.
  • Bleeding disorders — This includes conditions such as hemophilia and Von Willebrand’s disease.

By itself, hematuria rarely causes symptoms. One exception is when the bladder has so much blood in it that clots form, and the flow of urine is blocked. This causes pain at the site of the blockage in the lower pelvis. Symptoms usually come from the cause of the hematuria and vary depending on the condition.

Diagnosis and Treatment

Your doctor will want a urine sample to confirm that you have hematuria. Once it has been confirmed that you have hematuria, they will ask about you and your family’s medical history, especially history of kidney disease, bladder problems or bleeding disorders. Your doctor also will ask about any recent trauma or strenuous exercise, recent viral or bacterial infections, the medications you take, and your symptoms, including more frequent urination, pain with urination and pain in your side. The doctor will ask you for a fresh urine sample for a urinalysis. Urine is analysed in the laboratory to look for protein, white cells and red cells to identify a kidney or bladder infection, or kidney inflammation (glomerulonephritis).

The treatment of hematuria depends on its cause. In general, people with exercise-related hematuria do not need any treatment other than to modify their exercise programs. People with drug-related hematuria will improve if they stop taking the medication that caused the problem. Antibiotics typically will cure infection-related hematuria.