Hematuria, the sudden appearance of blood during urination, is a symptom that causes alarm. Whether the urine appears faintly pink, red, or contains visible clots, this indicates that red blood cells are entering the urinary tract somewhere between the kidneys and the urethral opening. Hematuria should always be investigated by a healthcare professional, even if it resolves or occurs only intermittently.
Determining the True Source of the Bleeding
The timing of the blood during urination offers the first clue about the source. Bleeding visible only at the start of the stream (initial hematuria) often points to a problem in the urethra or, in men, the prostate. Terminal hematuria, where blood appears right at the end of voiding, suggests the source is likely located in the bladder neck or the prostate. If the urine is bloody throughout the entire process (total hematuria), the issue is typically higher up, originating in the bladder, ureters, or kidneys.
It is important to consider that the blood may not be coming from the urinary tract. In women, bleeding can originate from the vagina, such as from menstrual spotting or endometriosis, and mix with urine during voiding. Rectal or anal bleeding, such as from hemorrhoids, can also be mistaken for hematuria. A doctor will use a urine test to confirm the presence of red blood cells and rule out other substances, like certain foods which can harmlessly change the urine color.
Common Causes Originating in the Lower Urinary Tract
The lower urinary tract (bladder and urethra) is the source of many frequent causes of hematuria. Urinary Tract Infections (UTIs), specifically cystitis (a bladder infection), are a common reason for blood in the urine. Cystitis occurs when bacteria, often E. coli, multiply in the bladder, causing inflammation of the lining. This irritation can lead to visible red blood cells, often accompanied by frequent, urgent urination or a burning sensation during voiding.
In men, an enlarged prostate gland (benign prostatic hyperplasia or BPH) is a frequent lower tract cause of bleeding, especially in older individuals. The prostate surrounds the urethra, and its enlargement can cause straining during urination, rupturing small blood vessels. Irritation or infection of the prostate (prostatitis) can also cause hematuria, along with pelvic pain and urinary frequency.
Other lower tract causes include bladder stones, which are hard mineral masses that cause bleeding by rubbing against the bladder wall. Temporary hematuria can also result from minor trauma due to prolonged, strenuous exercise, such as long-distance running. Urethritis, inflammation of the urethra often caused by sexually transmitted infections, may also cause bleeding noticed at the beginning of the urine stream.
Potential Causes Originating in the Kidneys and Upper Tract
Bleeding originating higher up in the urinary system (kidneys or ureters) often signals more complex issues. Kidney stones (nephrolithiasis) are a common upper tract cause, involving hard mineral deposits moving from the kidney into the narrow ureter. This movement causes severe, wave-like pain in the flank or side, and the stone’s scraping action leads to bleeding.
Pyelonephritis, an infection spread to the kidneys, is a severe form of UTI that causes hematuria. Unlike simple cystitis, pyelonephritis includes symptoms such as fever, chills, nausea, and intense pain in the flank or lower back. Certain kidney diseases, particularly glomerulonephritis, also cause blood in the urine. This condition involves inflammation of the glomeruli, the kidney’s tiny filtering units, allowing red blood cells to leak into the urine.
Cancer in the urinary tract (kidneys, ureters, or bladder) must also be investigated. Bladder cancer is the most frequent malignancy causing visible hematuria, often presenting as painless bleeding that comes and goes. Risk factors like advanced age, smoking history, and occupational chemical exposure increase the likelihood of these cancers. Early detection through a professional evaluation is important for successful treatment.
When Immediate Medical Evaluation is Necessary
Any episode of visible blood in the urine warrants evaluation by a medical professional. Immediate emergency care is necessary if hematuria is accompanied by an inability to urinate, which indicates a blockage from a large blood clot. Severe back or abdominal pain paired with fever, chills, or vomiting also signals an urgent problem, such as a severe kidney infection or an obstructing stone.
The diagnostic process begins with a urinalysis and urine culture to confirm red blood cells and check for bacterial infection. If infection is ruled out, further investigation is necessary, often including imaging tests (ultrasound or CT scan) to visualize the urinary tract. A cystoscopy may be performed for a detailed look at the bladder lining.