Introduction
A leukemoid reaction is a short-term rapid increase in the count of white blood cells that can sometimes mimic the condition of leukemia. The reaction usually occurs in response to infections, tumors, or pharmacological drug side effects. Leukemia, a cancer of the bone marrow and lymphatic tissues, is characterized by the presence of neoplastic cells in the affected individual's bone marrow. People suffering from leukemia usually have a very high count of white blood cells. A person diagnosed with leukemoid reaction does not necessarily have cancer, but it can pose a serious health hazard that needs immediate treatment. Blood counts are often returned to normal when the underlying infection is treated.
What Is a Leukemoid Reaction?
A leukemoid reaction is defined as a rapid increase in the cell count of leukocytes (white blood cells), usually more than 50,000 cells per microliter of blood.
For reference purposes, the normal white blood cell count in humans ranges from,
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In Men: The white blood cell count is 5000 to 10000 white blood cells per microliter.
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In Non-Pregnant Women: The white blood cell count is 4500 to 11000 white blood cells per microliter.
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In Children: The white blood cell count is 5000 to 10000 white blood cells per microliter.
Usually, an increase in the mature multi-lobed neutrophils and immature granulocytes is observed in the blood profile of the individual. These white blood cells (leukocytes) play a crucial role in the body’s immune system's first-line defense. Neutrophils are found to be the most commonly present leukocytes in the bloodstream of the patient. They act as first-line defense cells to indulge in phagocytosis to destroy foreign agents and bacteria. Immature granulocytes are often released into the bloodstream at the time of some bacterial infection or inflammatory reaction. They send signals to other white blood cells to act immediately and attack the foreign invaders.
What Are the Types of Leukemoid Reactions?
Leukemoid reactions are further classified depending on the kind of white blood cells elevated in the patient's blood.
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Granulocytic Reaction: It is the most frequently occurring leukemoid reaction type. It is usually marked by an increase in the count of neutrophils in response to some infections, solid tumors, and bacteria.
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Lymphocytic Reaction: This type of leukemoid reaction marks an increase in the number of lymphocytes. A lymphocytic reaction usually occurs as an immune response to malignant cells.
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Monocytic Reaction: A monocytic type of leukemoid reaction is characterized by an increase in the number of leukocytes called monocytes. Monocytes are seen to multiply in response to some infections or traumatic injuries.
What Are the Clinical Features of Leukemoid Reactions?
The leukemoid reaction is a condition characterized as responsive, excessive leukocytosis with the number of white blood cells exceeding 50,000 per microliter of blood outside the affected person’s bone marrow in the absence of any cancer. Symptoms largely vary depending on the underlying pathologic cause of the leukemoid reaction.
A persistent increase in the neutrophil count with both mature and immature granulocytes is known as a leukemoid reaction. An elevation in the number of leukocytes (white blood cells) is usually a symptom of the other underlying disease, and the symptoms associated with that disease are often experienced by the patient. Affected individuals might experience any of these symptoms:
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Fever and chills.
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Loss of consciousness.
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Frequent bleeding and easy bruising.
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Loss of weight.
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Generalized pain.
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Nausea and vomiting.
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Pain in the abdomen.
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Tiredness.
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Poor healing of wounds.
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Difficulty breathing.
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Jaundice.
What Are the Causes of Leukemoid Reactions?
A leukemoid reaction is usually caused due to a variety of conditions that include stress or inflammatory reaction in the body. The following conditions can be linked to leukemoid reactions.
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Sepsis (life-threatening medical condition).
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Organ transplant rejection.
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Solid tumors.
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Ethylene glycol toxicity.
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Infections like tuberculosis, diphtheria, etc.
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Corticosteroid drug usage.
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Severe bleeding tendency.
How to Diagnose Leukemoid Reaction?
A leukemoid reaction is usually diagnosed when the white blood cell counts are above 50,000 cells per microliter of blood and the patient does not have blood cancer. Blood is drawn from the arm of the patient to perform a complete blood cell count to measure the total leukocyte count. The healthcare professional can easily use a peripheral blood smear to differentiate between leukemia and leukemoid reaction. In a peripheral blood smear test, the pathologist microscopically examines the blood sample.
Numerous other tests can also be conducted to exclude the possibility of other conditions or to find the exact underlying pathology. The following tests may be included-
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Other hematological tests.
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Urine tests.
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Extensive physical examination.
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Diagnostic imaging.
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Bone marrow biopsy.
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Genetic tests.
What Stain Can Be Used for Leukemoid Reaction?
Leukocyte alkaline phosphatase (LAP) is the stain that can be used for leukemoid reaction. The activity of this stain can be used to differentiate chronic myelogenous leukemia from a leukemoid reaction. Leukocyte alkaline phosphatase is a cytochemical stain that can be used to determine the activity of alkaline phosphatase enzyme in the neutrophils and neutrophil bands.
What Is the Treatment of Leukemoid Reaction?
Identifying and targeting the underlying pathologic cause responsible for causing the disease is very important to treat the leukemoid reaction. For instance, in the case of a bacterial infection like tuberculosis, the condition should be cured using antibiotics to treat the leukemoid reaction.
Underlying malignancy can be treated with the following therapies:
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Radiotherapy.
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Chemotherapy.
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Immunotherapy.
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Surgery.
Alcoholic hepatitis can be treated by:
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Cessation of alcohol consumption.
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Multivitamin and nutrient supplementation.
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Liver transplantation.
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Certain pharmacological drugs.
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Counseling of the patient.
Conclusion
A leukemoid reaction is characterized by an increase in the count of white blood cells (leukocytes) in response to an infection. The prognosis of a leukemoid reaction is dependent on the underlying pathologic cause. Blood cells are usually returned to their normal levels once the underlying cause is eliminated. Therefore, it is very important to identify and treat the underlying pathology. With proper diagnostic tests, it is able to differentiate between leukemia and leukemoid reaction. The affected individual should immediately visit the doctor in case of any alarming signs and symptoms. It is a curable condition.
