Leukocytes, commonly known as white blood cells, are specialized cells that serve as a part of the body’s immune system. Their primary role involves defending the body against foreign invaders like bacteria, viruses, and other harmful substances. When these cells are detected in urine, it suggests that the body is responding to some form of irritation or abnormality within the urinary system.
Understanding Leukocytes in Urine
Leukocytes are continually produced in the bone marrow and circulate throughout the bloodstream and tissues, acting as the body’s primary defense against infection. When an infection, inflammation, or injury occurs anywhere in the body, leukocytes migrate to that specific area to neutralize the threat. Their presence in urine, a condition known as pyuria, indicates that this immune response is occurring within the urinary tract.
While a healthy person typically has few to no leukocytes in their urine, higher numbers often signal an underlying issue. Even small amounts can be detected by a urine dipstick test. The presence of leukocytes is a symptom of an underlying condition rather than a condition itself, prompting further investigation.
Common Causes of Leukocytes in Urine
The detection of leukocytes in urine can be attributed to several conditions, with infections being the most frequent cause. Urinary tract infections (UTIs) are a primary culprit, occurring when bacteria enter and multiply within any part of the urinary system, commonly the bladder or urethra. Common symptoms accompanying UTIs include a frequent urge to urinate, painful or burning sensations during urination, and sometimes cloudy or foul-smelling urine.
Kidney infections represent a more severe type of UTI where bacteria ascend from the bladder to the kidneys. The kidneys become inflamed, leading to an increase of white blood cells in the urine. These infections can cause symptoms beyond typical UTI discomfort, such as fever, chills, and pain in the back or side.
Leukocytes can also appear in urine due to non-infectious inflammation, known as sterile pyuria when no bacterial growth is found. Interstitial cystitis, a chronic bladder condition causing pain and pressure, is one example where the bladder lining becomes inflamed, leading to leukocytes in the urine without a bacterial infection. Kidney stones can also cause irritation and blockages in the urinary tract, leading to inflammation and the presence of leukocytes.
Sexually transmitted infections (STIs) such as chlamydia and gonorrhea can also trigger an inflammatory response in the urinary tract. In women, vaginal infections like vaginitis can cause leukocytes to appear in a urine sample due to contamination. Similarly, in men, inflammation of the prostate gland, known as prostatitis, can lead to leukocytes in urine. Certain medications, autoimmune conditions like lupus, and some cancers of the urinary system can also contribute to elevated leukocyte levels in urine.
When to Consult a Healthcare Professional
If leukocytes are detected in a urine test, consult a healthcare professional for an accurate diagnosis. While some urinary symptoms might resolve on their own, certain signs warrant prompt medical attention. These include severe pain, a high fever, persistent painful urination, or the presence of blood in the urine. Lower back or side pain, nausea, and vomiting also indicate a need for immediate evaluation.
A healthcare professional can determine the underlying cause through further diagnostic tests. A urinalysis will confirm the presence and amount of leukocytes, and a urine culture can identify specific bacteria if an infection is suspected. Imaging tests may be used to identify kidney stones, blockages, or other structural abnormalities. Blood tests might also assess for systemic infections or kidney damage. Treatment will depend on the diagnosis, from antibiotics for bacterial infections to other specific interventions for non-infectious causes.