Neutropenia is an abnormally low level of neutrophils in the blood. Neutrophils are white blood cells (WBCs) produced in the bone marrow and comprise approximately 60% of the blood. These cells are critically important to an immune response and migrate from the blood to tissues during an infection. They ingest and destroy particles and germs. Germs are microorganisms such as bacteria, protozoa, viruses, and fungus that cause disease. Neutropenia is an especially serious disorder for cancer patients who may have reduced immune functions because it makes the body vulnerable to bacterial and fungal infections. White blood cells are especially sensitive to chemotherapy. The number of cells killed during radiation therapy depends upon the dose and frequency of radiation, and how much of the body is irradiated.
Neutrophils can be segmented (segs, polys, or PMNs) or banded (bands) which are newly developed, immature neutrophils. If there is an increase in new neutrophils (bands) this may indicate that an infection is present and the body is attempting a defense. Neutropenia is sometimes called agranulocytosis or granulocytopenia because neutrophils display characteristic multi-lobed structures and granules in stained blood smears.
The normal level of neutrophils in human blood varies slightly by age and race. Infants have lower counts
Neutropenia has no specific symptoms except the severity of the patient's current infection. In severe neutropenia, the patient is likely to develop periodontal disease, oral and rectal ulcers, fever, and bacterial pneumonia. Fever recurring every 19-30 days suggests cyclical neutropenia.
Diagnosis is made on the basis of a white blood cell count and differential. The cause of neutropenia can be difficult to establish and depends on a combination of the patient's history, genetic evaluation, bone marrow biopsy, and repeated measurements of the WBC. However, in cancer patients it is usually an expected side effect of chemotherapy or radiation. The overall risk of infection is dependent upon the type of cancer an individual has as well as the treatment received. Patients at greater risk include those with hematologic malignancies, leukemia/lymphoma (cancers) and those who receive bone marrow transplants.
It is important to detect infections early. Some signs that indicate infection include:
Neutropenia may result from three processes:
Lowered production of white blood cells is the most common cause of neutropenia. It can result from:
WBCs are used and die at a faster rate due to:
Sequestration and margination are processes in which neutrophils are removed from the general blood circulation and redistributed within the body. These processes can occur because of:
Often the infections that develop in a cancer patient are opportunistic infections. That is, the organisms responsible for the infection normally would not cause disease in a healthy person, but do so in a cancer patient because the immune system is weak. Several steps can be taken on a daily basis to reduce the risk of developing an infection.
Treatment of neutropenia depends on the underlying cause.
Patients with fever and other signs of infection are treated with antibiotics. Some antibiotics used in the treatment of cancer patients include imipenem, meropenem, aminoglycoside, antipesudomonal penicillin, rifampin, and vancomycin. Combination therapy can be used that uses several types of antibiotics to stop the infection, but some of the drugs may be toxic or costly.
Patients receiving chemotherapy for cancer may be given drugs even in health to help restore the WBC to normal. A blood growth factor called sargramostim (Leukine, Prokine) stimulates WBC production. Another commonly used medication to reduce neutropenia in cancer patients is the cytokine G-CSF (granulocyte colony-stimulating factor, or filgrastim by Amgen-Roche). This substance is normally produced in the body at low levels. G-CSF helps the body produce more neutrophils to fight infection. This is especially useful in that many bacteria can not be killed by antibiotics due to antibiotic resistance.
Throughout the course of treatment it is important that the patient be monitored closely. This requires hospitalization for some patients, while others may be adequately treated at home.
A healthy lifestyle should be adopted that includes good nutrition, plenty of sleep, and appropriate levels of exercise. Avoid uncooked foods that may contain harmful bacteria. A nutritionist should be consulted to determine an appropriate, healthy diet.
Psychological stress can also weaken the immune system, making a person more susceptible to illness. It is important to find emotional support through family, friends, support groups, or through spiritual means.
See Also Immunologic therapies; Infection and sepsis; Chronic myelocytic leukemia
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American Cancer Society. <http://www.cancer.org>
Mayo Clinic. <http://www.mayoclinic.com>
WebMd. <www.webMD.com>
National Neutropenia Network, Inc. <http://www.neutropenia.org>
University of Pennsylvania Oncolink <http://www.oncolink.upenn.edu>
Rebecca Frey, Ph.D.
Jill Granger, M.S.
—A rare genetic blood disorder in which the patient's neutrophil level drops below 500/mm 3 for six to eight days every three weeks.
—A type of protein produced by immune cells that affects the actions of other cells. Differential —A blood cell count in which the percentages of cell types are calculated as well as the total number of cells.
—Any of several types of white blood cells that have granules in their cell substance. Neutrophils are the most common type of granulocyte.
—A granular white blood cell that ingests bacteria, dead tissue cells, and foreign matter.
— A type of infection caused by an organism that would not normally cause disease in a healthy person, but can do so when the immune system of the host is weakened.
—A medication made from yeast that stimulates WBC production. It is sold under the trade names Leukine and Prokine.
—The removal of neutrophils from circulating blood by cell changes that trap them in the lungs and spleen.
—G-CSF cytokine normally produced in the body at low levels. G-CSF helps the body produce more neutrophils to fight infection.