Understanding White Blood Cells and Leukocytosis
White blood cells (WBCs), also called leukocytes, are a critical part of the immune system, produced in the bone marrow and found in the blood and lymph tissue. They are the body's defense against invading organisms like bacteria and viruses, as well as foreign substances. An increase in their number, known as leukocytosis, indicates an active immune response or an underlying health issue. This increase can involve one or more of the five main types of white blood cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Symptoms and Presentation
Often, a high WBC count doesn't cause its own symptoms, and any signs you notice are from the underlying condition that caused the increase. These symptoms can be varied and may include fever, fatigue, weakness, pain, and night sweats. However, in extreme cases of leukocytosis, symptoms can be more severe, including difficulty breathing, vision problems, and bleeding.
Common Causes of an Elevated White Blood Cell Count
Infections and Inflammation
Bacterial and viral infections are the most common reasons for an elevated WBC count. As the body detects these invaders, it rapidly produces more white blood cells to combat them. Inflammatory diseases, such as rheumatoid arthritis or inflammatory bowel disease, also trigger a rise in WBCs due to chronic inflammation.
Medications and Environmental Factors
Certain medications, particularly corticosteroids, can cause leukocytosis. Other triggers include excessive physical or emotional stress, smoking, burns, and allergies. Pregnancy is also known to cause a temporary rise in the white blood cell count due to the stress the body undergoes.
Post-Surgical Effects
Following surgery, especially a splenectomy (removal of the spleen), a person's WBC count can increase. This happens because the spleen typically removes old blood cells, and its absence affects the balance.
Serious Underlying Causes of Leukocytosis
While often a benign response, a high white blood cell count can sometimes indicate a more serious condition, particularly if the count is extremely high or persistent.
Blood Cancers and Bone Marrow Disorders
One of the most concerning causes is certain blood cancers, such as leukemia and lymphoma. In these cases, the bone marrow produces an excessive number of abnormal white blood cells. Other bone marrow disorders, like polycythemia vera or myelofibrosis, can also lead to leukocytosis.
Hyperleukocytosis and Hyperviscosity Syndrome
In rare but severe cases, typically associated with acute leukemia, the WBC count can become so high (above 100,000 cells/µL) that the blood thickens, a condition known as hyperviscosity syndrome. This medical emergency can lead to serious complications, including stroke, breathing problems, and bleeding. The severity of the symptoms depends heavily on the specific type of leukemia and the WBC count.
Diagnosing a High White Blood Cell Count
To determine the cause of an elevated WBC count, a healthcare provider will start with a physical exam and a review of your medical history.
- Complete Blood Count (CBC) with Differential: This is a standard blood test that measures the total WBC count and the percentage of each type of white blood cell. A differential can help narrow down the cause by showing which specific type of cell is elevated.
- Further Testing: If initial results or symptoms suggest a more serious issue, your doctor may order additional tests. This can include a bone marrow biopsy, flow cytometry, and genetic testing, especially when evaluating for blood cancers.
Comparison of Leukocytosis Causes
| Feature | Infectious or Inflammatory Leukocytosis | Malignant Leukocytosis (e.g., Leukemia) |
|---|---|---|
| Onset | Often acute, developing quickly in response to illness. | Can be acute or chronic, developing over weeks, months, or years. |
| WBC Levels | Typically moderately elevated, though severe infections can cause very high counts (leukemoid reaction). | Counts can be extremely high, often >100,000 cells/µL. |
| Cell Appearance | Mature, functional white blood cells. | Often immature or abnormal white blood cells. |
| Associated Symptoms | Fever, fatigue, pain, and localized swelling corresponding to the infection. | Unexplained weight loss, night sweats, fatigue, and easy bruising or bleeding. |
| Treatment | Antibiotics for bacterial infections, anti-inflammatory medications for inflammation. | Chemotherapy, radiation, or stem cell transplantation. |
Treatment for High White Blood Cells
Treatment for leukocytosis is not aimed at lowering the WBC count itself but at addressing the underlying cause. A specific treatment approach will be determined based on your diagnosis.
- Infections: Bacterial infections are treated with antibiotics, while most viral infections resolve on their own.
- Inflammatory Conditions: Autoimmune diseases are managed with medications that suppress the immune system, such as steroids or other immunosuppressants.
- Cancer: Blood cancers like leukemia require specialized care, which may include chemotherapy, radiation therapy, or stem cell transplants.
- Medication Adjustment: If a drug is causing the high count, your doctor may adjust your dosage or switch to an alternative.
- Severe Cases: For extreme hyperleukocytosis, emergency procedures like leukapheresis may be used to quickly remove white blood cells from the bloodstream.
Conclusion: The Importance of Identifying the Root Cause
When you ask, what happens when white blood cells get high, the answer is that your body is sending a message. Leukocytosis is not a disease in itself but rather a sign that something is happening within your body. The proper diagnosis of the underlying cause is the most crucial step, as this dictates the correct course of treatment. If a routine blood test shows an elevated WBC, a healthcare provider can conduct further evaluation to pinpoint the source and manage the condition, whether it's a simple immune response or a more complex issue. You can learn more about leukocytosis and its causes based on information from the Cleveland Clinic.
Note: This article is for informational purposes only and does not constitute medical advice. You should always consult with a healthcare provider for diagnosis and treatment.
