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Neutropenia (noo-troe-PEE-nee-uh) is an abnormally low count of neutrophils, a type of white blood cell that helps fight off infections, particularly those caused by bacteria and fungi.
The threshold for defining neutropenia varies slightly from one medical practice to another. Neutropenia in adults is generally defined as a count of 1,700 or fewer neutrophils per microliter of blood. The cell count indicating neutropenia in children varies with age.
The lower your neutrophil count, the more vulnerable you are to infectious diseases. If you have severe neutropenia fewer than about 500 cells per microliter of blood bacteria normally present in your mouth and digestive tract can cause infections.
Symptoms of Neutropenia
Neutropenia itself often doesn’t cause symptoms. In some cases, people only learn they have neutropenia when they have a blood test for an unrelated reason. But people may have other symptoms from infection or the underlying problem causing the neutropenia.
Infections can occur as a complication of neutropenia. They occur most often in the mucous membranes, such as the inside of the mouth and the skin.
These infections can appear as:
- Abscesses (collections of pus)
- Wounds that take a long time to heal
- Fever is also a common symptom of infection.
The risk for serious infection generally increases as:
- Neutrophil count goes down
- Duration of severe neutropenia gets longer
Causes of Neutropenia
Neutropenia can develop if neutrophils are used up or destroyed in the bloodstream faster than the bone marrow can make new ones. With some bacterial infections, some allergic disorders, and some drug treatments, neutrophils are destroyed faster than they are produced. People with an autoimmune disease can make antibodies that destroy neutrophils and result in neutropenia. People with an enlarged spleen (see see Enlarged Spleen) may have a low neutrophil count because the enlarged spleen traps and destroys neutrophils.
Neutropenia can also develop if the production of neutrophils in the bone marrow is reduced, as can occur in some people with cancer, viral infections such as influenza, bacterial infections such as tuberculosis, myelofibrosis, or deficiencies of vitamin B12 or folate (folic acid). People who have received radiation therapy that involves the bone marrow may also develop neutropenia. Many drugs, including phenytoin, chloramphenicol, sulfa drugs, and many drugs used in cancer treatment (chemotherapy), as well as certain toxins (benzene and insecticides) can also impair the bone marrow’s ability to produce neutrophils.
How is Neutropenia Treated?
Treatment of neutropenia is based upon the underlying cause, severity, and the presence of associated infections or symptoms as well as the overall health status of the patient. Obviously, treatment must also be directed toward any underlying disease process. Treatments that directly address neutropenia may include (note that all of these treatments may not be appropriate in a given setting):
- antibiotic and/or antifungal medications to help fight infections;
- administration of white blood cells growth factors (such as recombinant granulocyte colony-stimulating factor (G-CSF, filgrastim) in some cases of severe neutropenia;
- granulocyte transfusions; or
- corticosteroid therapy or intravenous immune globulin for some cases of immune-mediated neutropenia.
Preventive measures may also be implemented in neutropenic patients to limit risk of infections. These measures might include strict attention to hand washing, use of private rooms, or in some cases, use of gloves, gowns, and/or face masks by caregivers.