Leukocytes, commonly known as white blood cells, are a fundamental part of the body’s immune system. While these cells are typically found in the bloodstream and tissues, their presence in urine generally signals an underlying health concern. An “abnormal” level of leukocytes in urine suggests that the body is mounting an immune response, often due to inflammation or an infection within the urinary tract. Elevated numbers indicate that medical attention may be needed.
Significance of Leukocytes in Urine
The detection of leukocytes in urine, a condition referred to as pyuria, is a significant indicator of inflammation or infection within the urinary system, which includes the kidneys, bladder, and urethra. Leukocytes are the immune system’s primary defense cells, and their increased presence in urine means they have migrated to the urinary tract to combat perceived threats. This response can be triggered by bacterial invasion, tissue irritation, or other inflammatory processes.
While pyuria suggests an issue, it does not pinpoint the exact cause or location. A typical range for leukocytes in urine is 0 to 5 white blood cells per high-powered field (WBC/HPF) under a microscope. Levels exceeding this, often 10 WBC/HPF or more, are considered abnormal and warrant further investigation. Their presence signals something is amiss within the urinary pathway, prompting a more specific diagnosis.
Common Causes Behind Elevated Leukocytes
Elevated leukocytes in urine often stem from urinary tract infections (UTIs), the most frequent cause. UTIs occur when bacteria enter the urinary tract, leading to an immune response that floods the area with white blood cells. This includes infections of the bladder (cystitis) or kidneys (pyelonephritis), where bacteria trigger inflammation and recruit leukocytes to fight the infection.
Kidney stones can also increase leukocytes in urine. As these mineral deposits travel through or obstruct the urinary tract, they cause irritation, inflammation, and potential blockages, attracting white blood cells. Sexually transmitted infections (STIs) like chlamydia, gonorrhea, and trichomoniasis are another cause, inducing inflammation in the genitourinary system that results in leukocytes appearing in urine.
Interstitial cystitis, a chronic bladder condition with pain and pressure, can cause sterile pyuria, where leukocytes are present without bacterial infection. Certain medications, including some nonsteroidal anti-inflammatory drugs (NSAIDs) and antibiotics, may contribute to sterile pyuria as a side effect. Improper urine sample collection can also lead to contamination from external sources, resulting in a false positive for leukocytes.
Associated Symptoms and When to Seek Care
When abnormal leukocytes are present in urine, individuals may experience symptoms depending on the underlying cause. Common indicators include painful or burning sensations during urination, a frequent and urgent need to urinate, and cloudy or foul-smelling urine. Some may also observe blood in their urine, which can appear red, pink, or cola-colored.
Other symptoms include lower abdominal pain, pelvic pressure, or pain in the back or sides, particularly if kidneys are affected. Systemic symptoms like fever, chills, nausea, and vomiting can also occur, especially with severe kidney infections.
Seek medical attention if these symptoms are present, particularly if severe, worsening quickly, or if you experience a high fever, extreme pain, or an inability to urinate. Prompt evaluation can help prevent complications.
Diagnostic Steps and Treatment Approaches
When abnormal leukocytes are detected, healthcare providers initiate diagnostic steps to identify the underlying cause. A urinalysis is a standard initial test, involving a dipstick test for leukocyte esterase (an enzyme in white blood cells) and a microscopic examination to count white blood cells. This test can also reveal abnormalities like nitrites, byproducts of certain bacteria.
Following a urinalysis, a urine culture may identify specific bacteria or microorganisms causing an infection and determine which antibiotics will be most effective. If initial tests are inconclusive or if conditions like kidney stones or structural issues are suspected, imaging studies such as ultrasound or CT scans may be recommended.
Treatment is tailored to the diagnosed cause. For bacterial infections, a course of antibiotics is typically prescribed. Depending on the severity and type, various antibiotics like trimethoprim/sulfamethoxazole, nitrofurantoin, or cephalexin may be used. For other conditions, treatment might involve pain management, kidney stone removal, or addressing the specific inflammatory process. Complete any prescribed treatment to ensure resolution.