Blood in the urine is called hematuria. Sometimes it’s visible to the naked eye. Sometimes it appears as blood cells that healthcare professionals can see under the microscope in a urine test.

Either way, people find hematuria scary. But in truth, it can be caused by many different medical conditions —ranging from mild to severe.

What Causes Hematuria?

Although hematuria should never be belittled, it’s a very common finding, especially in the laboratory. According to a study published in the US National Library of Medicine, the prevalence of microscopic blood in the urine is 1.7% to 31.1% and 4% to 5% in routine clinical practice.

The good news is that having blood in the urine is not always a sign of a life-threatening disease. Statistically, only 2% of people with microscopic hematuria could have bladder cancer. However, the number increase to 20% in patients with gross (visible) hematuria.

Other medical conditions that can cause blood in the urine include:

• Urinary tract infections (UTI).  These are infections that affect the organs of your urinary system, most commonly the bladder and the urethra. The presence of bacteria in these areas can be asymptomatic or involve both hematuria and other symptoms, such as frequent and/or painful urination. If the infection is left untreated and ascends to the kidneys, the diagnosis changes to pyelonephritis, and you can have back or flank pain, fever, and vomiting.

         Note that women are more prone to suffer from UTIs than men because they have a shorter urethra, making it easier for the bacteria to reach their bladder.

• Urinary stones. Bladder or kidney stones are solid deposits made of mineral salts of the urine. When these mineral salts are produced in excess, they can crystallize and form one or several masses, which often go undetected until they move through your urinary tract.

         Apart from hematuria, urinary stones usually cause severe pain in the back or the lower abdomen. Additionally, they can induce blockages and infections. But they’re easily treated with                 medication to pass them, or minimally invasive surgeries if they’re too big for that.

• Urinary tract injuries.  Accidents resulting in blunt or penetrating trauma in any part of the urinary system may lead to traumatic hematuria. Catheters can also hurt the urethra and cause bleeding.
• Exercise. Some athletes find macroscopic blood in their urine after long endurance activities. Intense workouts can lead to dehydration and the rupture of red blood cells, which eventually causes hematuria. While this is considered normal, it’s also recommended to get a medical checkup to rule out any other reasons for the condition.
• Medications. Blood thinners like warfarin and heparin are known to cause blood in the urine. But hematuria can also be a side effect of other medications, like aspirin, penicillin, and the chemotherapy drug cyclophosphamide (Cytoxan).Other medications don’t really cause hematuria, but as it happens with the consumption of beetroots or rhubarb, they may dye your urine red, pink, or brown —without it meaning it’s actual blood. This is what occurs with rifampin and senna laxatives.
• Benign or malignant tumors. Advanced cancer of the kidney, bladder, or prostate, can result in blood in the urine. But there’s also a common cause of hematuria in middle-aged and older men that’s called benign prostatic hyperplasia (BPH). In BPH, the prostate gland becomes enlarged due to the proliferation of its cells in a non-cancerous way.
• Polycystic kidney disease. PKD is a hereditary condition that fills the kidneys with cysts made of fluid. About 40% of people with PKD present blood in their urine. Other symptoms include flank pain, excessive urination, and arterial hypertension.
• Other disorders. Hematuria can also be caused by glomerulonephritis (the inflammation of the capillaries of the kidney that conduct filtration), blood disorders like sickle cell anemia and hemophilia, and autoimmune diseases.

How Is Hematuria Treated?

Whether it’s microscopic or macroscopic hematuria, your doctor will perform a series of tests to determine what’s causing it and then decide how to proceed.

When there’s blood in your urine, you can expect your doctor to carry out:

• Physical exams. In men, rectal exams help detect prostate problems. In women, pelvic exams help detect bladder problems.

• Urinalysis. Samples of your urine can be tested in the laboratory to verify the presence of blood, and/or to look for signs of its causes. For example, a high white blood cell count in the urine may indicate that you have a UTI.

• Cystoscopy. It’s an outpatient procedure in which the doctor inserts a narrow tube with a small camera into the urethra and up into the bladder to check them from the inside.

• Kidney biopsy. If it’s necessary, your doctor may take a sample of your renal tissue to study it. This procedure is executed under local anesthesia.

Additionally, your doctor could ask for a blood test, MRI, or any other tests that serve him or her to confirm a diagnosis. 

The treatment for hematuria depends on the diagnosis. For example, if you have a UTI, your doctor may resort to a urine culture to identify the germs that are causing the infection and prescribe the most accurate antibiotics for you.

Urinary tract cancers are usually treated with chemotherapy, radiation therapy, and/or surgery to extract the affected organ partially or completely. For example, the surgeon may remove the bladder and conduct a urinary diversion to reroute the urine out of your body through an opening in the abdomen and into a collecting bag. Or they may create a new bladder out of loops of the intestine. This new bladder can be directly connected to the urethra or it may need to be manually emptied with a catheter.

Sometimes, the cause of hematuria can’t be identified, and therefore, there’s no applicable treatment. Many times, the blood in the urine disappears on its own.

But if there’s blood in your urine, don’t dismiss it, even if it’s a small amount and/or you only see it once. Pay a visit to your healthcare professional and get yourself examined as soon as possible.