Can Blood in Urine Go Away on Its Own?

Lael Stieglitz, M.D., a urologist at Baptist MD Anderson Cancer Center in Jacksonville, Florida, has seen dozens of men in their 20s come to her office because they saw blood in their urine. Both the CT scan and cystoscopy—the use of a tiny camera to see inside the bladder—results were negative, and the blood eventually went away on its own.

In these cases, the blood in the urine was the result of strenuous exercise and dehydration affecting the prostate.

"The prostate is a very vascular organ, and it can have some superficial veins," Stieglitz said. "If you're really straining or bearing down, you can burst one of those veins and pee some blood. Or if you're really dehydrated and do a lot of vigorous exercise, you can cause trauma and have prostate bleeding."

'The blood in the urine is the smoke, not the fire.'

Stieglitz has also seen older men on blood thinners who struggle with constipation pee blood because of a prostate bleed.

All cases of hematuria (blood in the urine) require a proper workup, even if the blood dissipates without treatment. Hematuria, which affects between 2 percent and 30 percent of people at some point in their life, is not normal.

"Don't ignore it," said Thomas Masterson, M.D., an assistant professor of urology at the Desai Sethi Urology Institute in the Miller School of Medicine at the University of Miami in Coral Gables, Florida. "Even if it does go away, that doesn't mean that you're fixed or it's better."

Hematuria could be a sign of a serious medical condition, such as bladder cancer or kidney cancer.

"Usually, in and of itself, the blood in the urine is really not the bad guy," Masterson said. "The blood in the urine is the smoke, not the fire."

In addition to vigorous exercise and dehydration, potential benign (non-cancerous) causes of transient hematuria include kidney stones, trauma, urinary tract infection (UTI), benign prostatic hyperplasia, cystitis (bladder inflammation) and certain medications.

"When we see blood in the urine, our first concern is always: Is it cancer or not?" Masterson said. "The whole purpose of most of the workup is really trying to determine if there is a cancer of the urinary system."

Blood shouldn’t be in the urine, and yes, cancer is a concern, but there can be many reasons for it to be there, Masterson added.

What are the types of hematuria?

Hematuria is grouped into two categories: microscopic and gross. With microscopic hematuria, you can't see blood when you pee, but red blood cells are visible under a microscope. The risk of cancer with microscopic hematuria is about 3 percent, Masterson said.

In gross hematuria, the blood is visible to the naked eye, which carries a higher risk of cancer.

"In the older patient population with risk factors, it can be as high as 30 percent," Masterson said.

Hematuria, be it microscopic or gross, is not to be trivialized or ignored.

A workup for hematuria involves imaging of the kidneys via ultrasound or computed tomography (CT) scan. The next step is the cystoscopy.

"The reason we do it is bladder cancer starts off somewhat like skin cancer where it's just an abnormality on the surface," Masterson said. "Those abnormalities are not going to be seen. Think of it almost like a mole. If you were to have a CT scan of your arm that has a mole on it, you're not going to see a mole on the CT scan. You actually have to go in with a camera to take a look at the surface of the bladder.

"The hope is that when it's microscopic hematuria, we're catching these things early when they're still treatable or potentially curable. Even though that risk of cancer is very small, if it's there, it's usually early stage and can be treated."

How is blood in urine treated?

Urologists need to treat the underlying cause of hematuria first, said Arthur L. Burnett, M.D., a professor of urology at Johns Hopkins School of Medicine in Baltimore.

If it's a small enough kidney stone, doctors will leave it alone. If it's big enough, they will treat it with one of a variety of treatments to eradicate it.

"If it's a bladder tumor, we may cut it out, and after it heals up, that hopefully resolves it," Burnett said. "If it's growing deeply into the structures of the urinary tract, sometimes that warrants a much more aggressive surgical treatment like removing a portion of the urinary tract."

If it's a UTI, the urologist treats the infection, usually with antibiotics. If it's an enlarged prostate, they can prescribe medications.

If the cause of the hematuria is dehydration, strenuous exercise or a bleeding vein on the prostate, Stieglitz advises patients to drink more fluids.

"I tell them to watch out how hard they work out," she said. "If it's constipation, I put a lot of patients on fiber to try to get them to not struggle with that, and also tell them to increase their fluids."

What is persistent microscopic hematuria?

Some patients will experience persistent blood in the urine, typically in the form of microscopic hematuria, and the urologist never finds the cause.

"They go through the whole workup, and then we check their urine again year after year, and there's blood that remains there," Masterson said. "We follow them very closely because they still could develop something later on."

If a patient has microscopic hematuria and no one can figure out why, it's likely because their kidney filters are leaky.

"It's called renal leak," Stieglitz said. "The idea is your kidneys are your filters—they clean all your blood out. If your filters leak a little bit, then some blood cells will get into your urine, and you'll have microscopic hematuria."

Bottom line: Hematuria, be it microscopic or gross, is not to be trivialized or ignored.

"It could be a signal of a serious condition and warrants a proper workup," Burnett said.

"Definitely find a urologist, even if it goes away," Stieglitz added.