Blood In Urine

Seeing blood in your urine can be alarming. While in many instances the cause is harmless, blood in urine (hematuria) can indicate a serious disorder.

Blood that you can see is called gross hematuria. Urinary blood that's visible only under a microscope (microscopic hematuria) is found when your doctor tests your urine. Either way, it's important to determine the reason for the bleeding.

Symptoms

Gross hematuria produces pink, red or cola-colored urine due to the presence of red blood cells. It takes little blood to produce red urine, and the bleeding usually isn't painful. Passing blood clots in your urine, however, can be painful. Bloody urine often occurs without other signs or symptoms.

Causes

In hematuria, your kidneys — or other parts of your urinary tract — allow blood cells to leak into urine. Various problems can cause this leakage, including:

• Urinary tract infections. These occur when bacteria enter your body through the urethra and multiply in your bladder. Symptoms can include a persistent urge to urinate, pain and burning with urination, and extremely strong-smelling urine.
• Kidney infections (pyelonephritis). These can occur when bacteria enter your kidneys from your bloodstream or move from your ureters to your kidney(s). Signs and symptoms are often similar to bladder infections, though kidney infections are more likely to cause a fever and flank pain.
• Kidney disease. Microscopic urinary bleeding is a common symptom of glomerulonephritis, an inflammation of the kidneys' filtering system. Glomerulonephritis may be part of a systemic disease, such as diabetes, or it can occur on its own. Viral or strep infections, blood vessel diseases (vasculitis), and immune problems such as IgA nephropathy, which affects the small capillaries that filter blood in the kidneys (glomeruli), can trigger glomerulonephritis.
• Cancer. Visible urinary bleeding may be a sign of advanced kidney, bladder or prostate cancer. Unfortunately, you might not have signs or symptoms in the early stages, when these cancers are more treatable.