Blood in the urine can have a handful of causes. While things may be minor, in some cases, it may need prompt treatment before it becomes a huge health issue. Medically speaking, blood in your urine is called hematuria and it basically has two types:

  • Gross hematuria: blood in the urine
  • Microscopic hematuria: blood in the urine only seen under a microscope
image source by NCI

The urinary tract

The urinary tract functions for excretion and removal of waste products and extra fluid in the body. It houses the following organs:

  • Two kidneys
  • Two ureters
  • A bladder
  • A urethra

The kidneys are the stars of the show. They are bean-shaped organs about the size of fist and are found just below the rib cage on each side. The kidney is responsible for filtering around 120 to 150 quarts of blood and normally produces around 1-2 quarts of urine containing waste products and extra fluid. But take note that children normally have less urine production than adults.

After the kidneys are done with their job, the urine is then sent to connective tubes called ureters then to the bladder where urine is stored. When the bladder empties, urine finally flows out of the body through a tube called the urethra.

Blood in the urine

Blood can basically come from any organs in your urinary tract. Gross hematuria is manifested by pink, red, or cola-colored urine which isn’t typically painful. Take note too that it does not take a lot of blood to produce red urine. But if blood clots are being passed rather than pure urine, then the story might be different. 

Other causes may be:

  • Bladder infections such as acute cystitis may cause:
    • Burning pain upon urination
    • Fever
    • Infants being grumpy and with no appetite
    • Strong urge to pee
    • Lower belly pain
  • Kidney infections or pyelonephritis may cause:
    • Fever
    • Chills
    • Pain in the lower back 
    • Flank pain
  • Kidney stones may cause:
    • Severe belly or pelvic pain
  • Kidney cancer may cause:
    • Weight loss
    • Appetite loss
    • Fatigue
    • Flank pain
  • Kidney diseases may cause:
    • Hypertension
    • Weakness
    • Swelling in the body

Causes of hematuria in females

Urinary tract infections (UTI)

Due to anatomical causes, females are more likely to develop UTI than males. As per the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), about 40-60% of women suffer a UTI in their lifetime. 

A common reason for UTI in females is when bacteria from feces enter the urethra and travel up the ureters, bladder, or kidneys. Symptoms of UTI are:

  • Painful urination
  • Cloudy or foul-smelling urine
  • Blood in the urine 
  • Pain or pressure in the abdomen, lower back, or pelvic area
  • Frequent and urgent need to urinate

Stones

Minerals in excess can end up forming stones in the bladder or kidneys. This can get painful as stones may tear or scratch the lining of the urinary tract organs. For the same reason, blood produced by this can be passed out via the urine causing hematuria. Urinary tract stones may cause the following:

  • Prink, brown, or red urine
  • Incontinence or involuntary urination
  • Frequent urination
  • Cloudy or foul-smelling urine
  • Painful urination

It’s worth noting that there are other things that may increase the risk for developing stones as per Urology Care Foundation:

  • Excessive salt consumption
  • Dehydration
  • Digestive conditions like ulcerative colitis or Crohn’s disease
  • Thyroid problems
  • Obesity 

Endometriosis

Endometriosis causes severe low back pain with blood in the urine and occurs in more than 11% adolescent and adult females in the USA. This condition occurs when the uterus lining grows external to the uterus. Endometriosis requires prompt treatment before it leads to infertility. 

Cancer

Kidney or bladder cancer may also cause hematuria but it typically is present one day and gone on the next. Additionally, bladder cancer can induce frequent urination. On the other hand, kidney cancer doesn’t affect urination as much, but it causes significant low back pain. 

Causes of hematuria in males

Urinary tract infections

While UTI occurs more in females, men can still develop this condition. Prostate problems and recent catheterization may pave the way for this infection. 

Kidney and bladder stones

Men can also develop stones in the urinary tract. More often than not, these stones are small enough to be excreted via the urine. However, larger stones may leave the kidney or bladder and dislodge other parts of the urinary tract. Symptoms are as follows:

  • Prink, brown, or red urine
  • Incontinence or involuntary urination
  • Frequent urination
  • Cloudy or foul-smelling urine
  • Painful urination

Exercise-induced hematuria (EIH)

EIH, also known as post-exertional hematuria, is basically blood in the urine post-exercise. While the main cause remains unknown, it is said to be associated with high-intensity exercise rather than the duration. Also, dehydration may increase this risk. 

A study conducted in 2014 with 491 healthy participants revealed that 12% ended up with EIH after a time-restricted 5-kilometer run while only 1.3% had it when asked to complete the same distance without any time limit. EIH typically resolves within 3 days but if it lasts for more than 2 weeks, better see a doctor!

Prostate enlargement

Benign prostatic hyperplasia (BPH) is a common condition that causes an enlarged prostate. The prostate is found only in men and it aids in semen production. It is located just below the bladder and in front of the rectum. 

An enlarged prostate can add pressure into the urethra making urination difficult. Due to this, the bladder will end up working harder which may lead to bleeding. BPH is said to affect about 50% of males aged 51-60. Symptoms are as follows:

  • Urge to urinate
  • Frequent urination, especially at night
  • Need to strain while urinating
  • Difficulty starting urination
  • Weak or intermittent urine flow
  • Blood in the urine
  • Feeling of full bladder after urinating
  • Inability to urinate in severe cases and is a medical emergency!

Recent catheterization

A urinary catheter (UC) is a flexible tube that drains urine from the bladder. It can be in two types: indwelling or external. An indwelling catheter is inserted into the urethra to access the bladder and may stay there for several days or weeks. An external one fits over the penis to collect urine into a drainage bag. 

Both types may lead to bacterial invasion ultimately leading to a catheter-associated UTI which can cause hematuria. As per the Center for Disease Control and Prevention (CDC), 75% of UTIs from hospital admission is due to the use of a catheter. 

Kidney injury

Glomerulonephritis (GN) is a kidney problem that affects the glomeruli, a structure within the kidney that helps it do its job of filtering the blood. This condition promotes the inability to eradicate waste and excess fluid and with no treatment, this can ultimately lead to kidney failure. 

Chronic GN typically occurs in young men with concomitant hearing and vision loss. On the other hand, acute GN may cause the following symptoms:

  • Blood in the urine
  • Puffiness of the face
  • Reduced urination
  • Shortness of breath
  • Hypertension
  • Coughing

Signs and symptoms of chronic GN may include:

  • Blood in the urine
  • Protein in the urine
  • Swelling of the face or ankles
  • Bubbly or foamy urine
  • Frequent nighttime urination

Medications

These medications may induce hematuria:

  • Blood thinners such as warfarin and aspirin
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Chemotherapy drugs such as cyclophosphamide and ifosfamide that can cause hemorrhagic cystitis
  • Long-term use of the laxative Senna

Prostate cancer

One in 10 men in the USA will be diagnosed with prostate cancer in their lifetime. The good thing here is that when diagnosed and treated early, prostate cancer is typically curable. Regular screening is key. Symptoms may include:

  • Dull pain in the lower pelvic area
  • Painful ejaculation
  • Pain in the lower back, hips, or upper thighs
  • Blood in the semen
  • Appetite loss
  • Bone pain
  • Unexplained weight loss

Causes of hematuria in children

Generally, hematuria in children is removed without any treatment. However, seeing a doctor is still highly encouraged as causes of hematuria in children includes the following:

  • UTI
  • Stones
  • Urinary tract injuries
  • Polycystic kidney disease

Risk factors

  • Age of 50 years old and above
  • Recent infection
  • Family history of kidney diseases or stones
  • Intake of certain medications such as NSAIDs, aspirin, and antibiotics like penicillin
  • High-intensity exercise

When to seek medical attention?

While most reasons for hematuria may be mild causes, there are signs you can look out for to signal you that it’s time to seek medical attention.

  • Frequent, difficult, or painful urination
  • Abdominal pain
  • Kidney pain
  • Nausea
  • Blood clot in the urine
  • Blood in the urine accompanied by the following:
    • Nausea
    • Vomiting
    • Chills
    • Fever
    • Pain in your back, side, or abdomen

Diagnosing hematuria

Medical history

This includes a review of symptoms and a list of prescription and over-the-counter medications taken by the patient. Current and past medications will also be asked.

Physical exam

  • Abdominal and back taps to check for pain or tenderness
  • Pelvic exam for females
  • Digital rectal exam of a man’s prostate and rectum to check for inflammation and enlarged

Urinalysis

white microscope on top of black table

A urinalysis can be done in a health care professional’s office via a dipstick to be sent out to a lab. However, this can give out false-positive results even without blood in the urine. The health care professional may also look for the presence of red blood cells under the microscope. Before obtaining a urine sample, it’s important to note the date of last menstruation since the presence of a period may result in a false-positive test for hematuria.

Additional tests

Now what if the urinalysis reveals too many red blood cells? The health care professional may order for further testing:

Blood test

A blood test may detect high levels of creatinine which indicates a problem with the kidney’s function. Additionally, a blood test can also look for signs of other diseases such as lupus and prostate cancer which may also be reasons for hematuria.

Computed tomography (CT) scan

Ct scans utilize both x-rays and computer technology to have a visual field of the urinary tract. The patient may be asked to drink a solution or have a contrast medium injected. Then, a tunnel-shaped device takes the x-rays. This can reveal urinary tract stones, obstructions, infections, tumors, cysts, and trauma.

Cystoscopy

This is a procedure done by a urologist, a doctor specializing in urinary problems. This is a means to see what’s inside the bladder and urethra with the help of a tube-like instrument called the cystoscopy. It can help detect bladder cancer.

Kidney biopsy

A kidney biopsy requires harvesting a small tissue from the kidney to be tested by a pathologist in the lab to check for the presence of kidney diseases. 

Magnetic resonance imaging (MRI)

This is done by taking images of the patient’s internal organs but without the use of x-rays this time. This is performed by a trained technician and the images are duly interpreted by a radiologist. Just like the CT scan, an MRI may also include the injection of a contrast medium for a better view of the organs. 

Tips to prevent hematuria

  • Drink lots of water
  • Pee immediately after sexual intercourse
  • Observe good hygiene 
  • Prevent excess salt intake
  • Limit chemical exposure

Last words

The urinary tract, especially the kidneys, are vital to life and it’s of our best interest to do everything we can to take care of them. Diet, nutrition, and physical activity can help prevent premature failure of these organs. Take care of your kidneys so your kidneys can take care of you!