Neutrophils are a type of white blood cells that protect the body from infection. They constitute about 45 to 75 percent of all white blood cells in the bloodstream.
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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.
Neutropenia is an abnormally low count of a specific type of white blood cell called a neutrophil. Neutrophils are stored in the bone marrow * and are the most common type of white blood cell, comprising between 45 and 75 percent of all the white blood cells. They are responsible for protecting the body against infection. When the neutrophil count is low (neutropenia), the body is at high risk for infection. Neutropenia can be classified as mild, moderate, or severe. The risk for infection increases as the neutropenia becomes more severe and also increases the longer the individual is neutropenic.
The most common cause of neutropenia is treatment with chemotherapy * or radiation therapy * for cancer. Chemotherapy drugs and radiation therapy kill body cells that are rapidly dividing, but they cannot tell the difference between normal cells and cancer cells, so while attacking cancer cells, they also damage or kill normal cells.
Additional causes of neutropenia include the following:
In infants, the most common cause of neutropenia is infection * . A severe infection may prevent the bone marrow from producing enough neutrophils. Neutropenia may also occur in infants when the mother had preeclampsia * during pregnancy. Neutropenia in infants is a lifethreatening condition.
People who are receiving chemotherapy for cancer are at highest risk for the development of neutropenia. Neutropenia occurs most commonly about 7 to 12 days after receiving a chemotherapy treatment.
Level of risk can vary with the different possible causes of neutropenia as described previously.
Although there are no obvious signs of neutropenia, frequent or unusual infections or infections that do not heal quickly may be indicators of neutropenia. Signs of infection include the following:
When signs of infection occur and do not resolve or get worse, the person should see a doctor for evaluation and treatment.
The doctor orders a blood test that provides a count of white blood cells with a breakdown of the types of white blood cells, including neutrophils. This test tells whether or not the neutrophil count is normal or too low. A bone marrow biopsy * may be required to determine the cause of the low neutrophil count.
The doctor may order laboratory tests (called cultures * ) of the blood and urine to determine if there is infection present and which antibiotics * will be most effective for treatment.
Treatment is often targeted toward clearing up any existing infection. When a person has neutropenia, an infection is a serious event that can lead to serious complications or death.
When the cause of the neutropenia is found, treatment will be targeted toward the cause. For example, if the cause of the neutropenia is an enlarged spleen, surgery to remove the spleen may resolve the problem.
Special medications that are designed to stimulate the production of white blood cells, including neutrophils, may be prescribed by the doctor. In patients receiving chemotherapy known to cause severe neutropenia, these medications may be ordered prior to the start of treatment with chemotherapy.
Results of cultures of the blood, urine, sputum, and/or wounds are used to determine therapy using specific antibiotics. If fever does not respond to antibiotic therapy within four to five days of initiation of treatment, antifungal medications may be ordered as the patient may have a fungal infection. Most severely neutropenic patients will be treated with intravenous antibiotics in an hospital setting where the effects of the antibiotics can be closely monitored.
A person may not be able to prevent neutropenia, but he or she can take precautions to avoid getting an infection.
Strategies to decrease the risk of getting an infection include:
See also Bacterial Infections • Cancer: Overview • Fever • Fungal Infections • Immune System and Other Body Defenses: Overview • Infection • Viral Infections
Akhtari, Mojitaba, Ihab El-Hemaidi, and Kam Newman, eds. Neutropenia: Causes, Signs, Symptoms and Treatment. Hauppauge, NY: Nova Science Publishing, 2015.
Klein, Christoph. Neutropenia: An Issue of Hematology/Oncology Clinics of North America. St. Louis, MO: Elsevier, 2013.
Centers for Disease Control and Prevention (CDC). “What You Need to Know: Neutropenia and Risk for Infection.” http://www.cdc.gov/cancer/preventinfections/pdf/neutropenia.pdf (accessed March 31, 2016).
Leukemia and Lymphoma Society. “Understanding the Side Effects of Drug Therapy.” http://www.lls.org/sites/default/files/file_assets/understandingdrugtherapy.pdf (accessed March 31, 2016).
MedlinePlus. “Neutropenia: Infants.” U.S. National Library of Medicine. http://www.nlm.nih.gov/medlineplus/ency/article/007230.htm (accessed March 31, 2016).
Merck Manual, Consumer Version. “Neutropenia.” http://www.merckmanuals.com/home/blood-disorders/white-blood-celldisorders/neutropenia (accessed March 31, 2016).
Centers for Disease Control and Prevention (CDC). 1600 Clifton Rd., Atlanta, GA 30329-4027. Toll-free: 800-CDC-INFO, 800-232-4636. Website: http://www.cdc.gov (accessed March 31, 2016).
Leukemia and Lymphoma Society. 1311 Mamaroneck Ave., Suite 310, White Plains, NY 10605. Telephone: 914-949-5213. Website: www.lls.org (accessed March 31, 2016).
* bone marrow is the soft, spongy area in the interior of the bones in which blood cells are produced.
* chemotherapy (KEE-mo-THER-apee) is the treatment of cancer with powerful drugs that kill cancer cells.
* radiation therapy is a treatment that uses high-energy radiation from x-rays and other sources to kill cancer cells and shrink cancerous growths.
* immune system (im-YOON SIStem) is the system of the body composed of specialized cells and the substances they produce that helps protect the body against disease-causing germs.
* aplastic anemia is a disease in which there is (A-plas-tik uh-NEEme-uh) a lack of or deficiency of all types of blood cells caused by the failure of the bone marrow to produce enough new blood cells.
* infection is (in-FEK-shun) the invasion and multiplication of disease-producing microorganisms, such as bacteria and viruses, in body tissues.
* digestive system is the system that processes food. It includes the mouth, esophagus, stomach, intestines, colon, rectum, and other organs involved in digestion, including the liver and pancreas.
* preeclampsia (PREE-eh-CLAMPsee-ah) is a complication of pregnancy characterized by high blood pressure, sometimes with fluid retention; it also indicates signs of damage to another organ, usually the kidneys.
* vagina (vah-JY-nah) is the canal, or passageway, in a woman that leads from the uterus to the outside of the body.
* biopsy (BI-op-see) is a test in which a small sample of skin or other body tissue is removed and examined for signs of disease.
* culture (KUL-chur) is a test in which a sample of fluid or tissue from the body is placed in a dish containing material that supports the growth of certain organisms. Typically, within days the organisms will grow and can be identified.
* antibiotic (an-tie-by-AH-tik) is a drug that kills or slows the growth of bacteria.
* contagious (kon-TAY-jus) means transmittable from one person to another, usually referring to an infection.