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Leukopenia (or leukocytopenia, or leucopenia, from Greek λευκό-white and πενία-deficiency) is a decrease in the number of circulating white blood cells (leukocytes) in the blood. As the principal function of white cells is to combat infection, a decrease in the number of these cells can place patients at increased risk for infection.

In pancytopenia, the other cell types in the blood (red blood cells and platelets) are similarly affected.

Neutropenia is a decrease in the number of circulating neutrophil granulocytes, the most abundant white blood cells. The terms leukopenia and neutropenia may occasionally be used interchangeably, as the neutrophil count is the most important indicator of infection risk. However, neutropenia is more properly considered a subset of leukopenia as a whole.

[edit] Causes

Low white cell counts are associated with chemotherapy, radiation therapy, leukemia (as malignant cells overwhelm the bone marrow), myelofibrosis and aplastic anemia (failure of white and red cell creation, along with poor platelet production). In addition, many common medications can cause leukopenia (eg. minocyclen, a commonly prescribed antibiotic).

Other causes of low white blood cell count include: Influenza, systemic lupus erythematosus, typhus, malaria, HIV, tuberculosis, dengue, Rickettsial infections, enlargement of the spleen, folate deficiencies, psittacosis and sepsis. Many other causes exist, such as a deficiency in certain minerals such as copper and zinc.

Pseudoleukopenia can develop upon the onset of infection. The leukocytes (predominately Neutrophils, responding to injury first) are marginalized in the blood vessels so that they can scan for the site of infection. This means that even though there is increased WBC production, it will appear as though it is low from a blood sample, since the blood sample is of core blood and does not include the marginalized leukocytes.

There are also reports of Leukopenia caused by Depakote (Divalproex Sodium or Valproic Acid), a drug used for epilepsy (seizures), mania (with bipolar disorder) and migraine.

[edit] Diagnosis

Leukopenia can be identified with a complete blood count.

[edit] Medications causing leukopenia

Some medications can have an impact on the number and function of white blood cells. Medications which can cause leukopenia include clozapine, an antipsychotic medication with a rare adverse effect leading to the total absence of all granulocytes (neutrophils, basophils, eosinophils). Other medications include immunosuppressive drugs, such as sirolimus, mycophenolate mofetil, tacrolimus, and cyclosporine. Interferons used to treat multiple sclerosis, like Rebif, Avonex, and Betaseron, can also cause leukopenia. The antidepressant and smoking addiction treatment drug Wellbutrin (Bupropion HCL) can also cause leukopenia with long-term use.

[edit] External links

• 1355808838 at GPnotebook
• 11-135a. at Merck Manual of Diagnosis and Therapy Professional Edition

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