Healthy Living

What Causes Blood in the Urine?

What Causes Blood in the Urine?

The presence of blood in the urine could cause anxiety. Although there are cases where the cause is actually not a cause of concern, some cases may also indicate a serious condition.

Blood in the urine is known as hematuria. The blood that you can see with your naked eye is referred to as gross hematuria, while blood that can only be seen through a microscope is called microscopic hematuria. It is important to find out the reason behind hematuria for proper treatment.

When a person has hematuria, either the kidneys or other parts of the urinary tract, let blood cells to leak into the urine. Various reasons could cause this leakage. 

Causes of Hematuria

Urinary Tract Infections

A urinary tract infection occurs when bacteria enters the body through the urethra. Then, the bacteria will start to multiply in the bladder. Symptoms of urinary tract infections include constant urge to urinate, pain when urinating, and a very strong-smelling urine.  In some cases, the symptom of urinary tract infections can only be seen in microscopic blood.

Kidney or Bladder Stone

Sometimes, the minerals that have been concentrated in the urine precipitate out, which will then form crystals on the walls of the bladder or kidneys. Eventually, the crystals will become little, hard stones. Usually, the stones are painless and won’t probably give a problem unless the stones are being passed or cause a blockage.

Kidney stones can cause unbearable pain and bleeding. Bladder stones can also result to gross or microscopic hematuria.

Kidney Infections

Also known as pyelonephritis, kidney infections can happen when bacteria invade the kidneys through the bloodstream or move up from the ureters to the kidneys. Symptoms of kidney infections usually include blood in the urine, flank pain, and fever.

Enlarged Prostate

The prostate gland is the organ located below the bladder. It encloses the top part of the urethra. When the prostate gland increases in size, it squeezes the urethra, which in turn partially blocks the flow of urine. An enlarged prostate is commonly known as benign prostatic hyperplasia or BPH. The signs and symptoms include persistent or urgent need to pass urine, difficulty urinating, and blood in the urine (either gross or microscopic). Similar signs and symptoms may also be observed in prostatitis or infection of the prostate. 

Kidney Disease

Glomerulonephritis is the inflammation of the filtering system of the kidneys. Microscopic urinary bleeding is the common sign of this condition. Glomerulonephritis can happen on its own or could be a part of a systemic disease like diabetes. It could also be triggered by blood vessel diseases, immune problems, and strep or viral infections. 

Kidney Injury

A blow or other traumatic injury, such as accident or contact sports to the kidneys, can cause hematuria. 


Urinary bleeding that’s visible in the eyes can be a sign of an advanced stage of bladder, kidney, or prostate cancer. Sadly, the signs and symptoms are not usually seen during the early stages of the disease.


Certain medications such as penicillin and the anti-cancer drug cyclophosphamide can cause urinary bleeding. Anticoagulants like aspirin may also cause gross hematuria. 

Inherited Disorders

Sickle cell anemia and Alport syndrome can cause urinary bleeding.

Strenuous Exercise

The link between hematuria and strenuous exercise is not yet clear. Although cases are rare, some are associated with trauma to the bladder or breakdown of the red blood cells, which occurs during a sustained aerobic exercise. Any athlete could develop hematuria after an extreme workout, but runners are most commonly affected. 

Whatever the cause of your hematuria, it is best to immediately contact a physician to have a proper treatment.