What Causes Leukocytes in Urine?

Causes leukocytes in urine

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The presence of leukocytes in urine is a significant indicator of various underlying health conditions, primarily infections and inflammations in the urinary tract and kidneys. Understanding the causes of leukocyturia is crucial for accurate diagnosis and effective treatment. Further research and diagnostic advancements will continue to enhance our understanding of this condition and improve patient outcomes.

Leukocytes, also known as white blood cells (WBCs), are a crucial component of the immune system, responsible for defending the body against infections and foreign substances. The presence of leukocytes in urine, a condition known as leukocyturia, can indicate various underlying health issues. This article explores the primary causes of leukocytes in urine, drawing on recent research findings.

Urinary Tract Infections (UTIs)

One of the most common causes of leukocytes in urine is urinary tract infections (UTIs). UTIs occur when bacteria, such as Escherichia coli (E. coli), enter the urinary tract and multiply, leading to infection. This condition is particularly prevalent in women due to their shorter urethra, which allows bacteria easier access to the bladder. Symptoms of UTIs include burning during urination, smelly urine, pelvic pain, nausea, and vomiting1 5.

Kidney Infections

Kidney infections, or pyelonephritis, are another significant cause of leukocytes in urine. These infections often start as UTIs that spread to the kidneys. Symptoms include fever, chills, back pain, and vomiting. Kidney infections can lead to serious complications if not treated promptly, as the infection can cause inflammation and damage to the kidneys1 5.

Chemotactic Factors

Research has shown that chemotactic factors in the urine can lead to an increase in leukocytes. Chemotactic factors are substances that attract leukocytes to the site of infection or inflammation. In patients with UTIs, certain urinary protein fractions exhibit chemotactic activity, leading to the infiltration of polymorphonuclear leukocytes in the local tissue4. This chemotactic activity is a significant factor in the elevated leukocyte count observed in urine during infections.

IgA Nephropathy

IgA nephropathy (IgAN) is a kidney disease characterized by the deposition of the immunoglobulin A (IgA) in the glomeruli, leading to inflammation. Leukocytes play a role in the pathogenesis of IgAN, with different chemokines such as monocyte chemotactic and activating factor (MCAF/MCP-1) and interleukin-8 (IL-8) being involved in the recruitment and activation of leukocytes in the kidneys. Elevated levels of these chemokines in urine are associated with different phases and pathological lesions of IgAN, contributing to leukocyturia2.

Kidney Stones

The presence of kidney stones can also lead to an increase in leukocytes in urine. Kidney stones are hard deposits of minerals and salts that form in the kidneys and can cause blockages in the urinary tract. This blockage can lead to infections and inflammation, resulting in elevated leukocyte levels. Symptoms of kidney stones include severe pain, vomiting, fever, and chills1 5.

Holding Urine

Holding urine for extended periods can create a breeding ground for bacteria in the bladder, leading to infections and an increase in leukocytes. Continuous holding of urine can cause bacterial infections in the bladder, which may spread to the kidneys if not addressed promptly1 5.

Diagnostic Considerations

Accurate diagnosis of leukocyturia requires appropriate urine sampling, rapid examination of the samples, and standardized examination conditions. Differentiating leukocytes into neutrophil or eosinophil granulocytes or lymphocytes can provide further insights into the underlying cause of leukocyturia. In the absence of significant bacteriuria, further diagnostic evaluation is necessary to determine the cause of leukocyturia3.