Neutropenia is an abnormally low level of neutrophils, a type of white blood cell. All white blood cells help the body fight infection. Neutrophils fight infection by destroying bacteria and fungi (such as yeast). People who have neutropenia are at increased risk for developing serious infections because there are not enough neutrophils to destroy harmful microorganisms that cause disease, such as bacteria. Neutropenia occurs in about half of people with cancer receiving chemotherapy and is common in people with leukemia.

Causes

Neutrophils and other types of white blood cells are made in the bone marrow (a spongy tissue found inside larger bones such as the pelvis, vertebrae, and ribs) and then circulate in the bloodstream. Cancer and cancer treatment can cause neutropenia in several ways:

• Some types of chemotherapy can cause the bone marrow to not work properly, lowering the production of neutrophils.
  
  
• Cancers that affect the bone marrow directly, including leukemia, lymphoma, and myeloma, or metastatic cancer (cancer that has spread) can crowd normal bone marrow cells.
  
  
• Radiation therapy can also affect the bone marrow, especially if given to several areas of the body or to bones in the pelvis, legs, chest, or abdomen.

People with cancer who are age 70 or older or people with a weakened immune system (due to factors such as HIV infection or a kidney transplantation) are at higher risk for neutropenia. People with severe or long-lasting neutropenia are more likely to develop an infection.

Signs and symptoms

Neutropenia itself does not cause any symptoms. Patients usually find out they have neutropenia from a blood test or when an infection develops. Because neutropenia is a common side effect of some types of chemotherapy, the doctor will do regular blood tests, usually a complete blood count (CBC), to look for neutropenia and other blood-related complications of chemotherapy.

For patients with neutropenia, even a minor infection can quickly become serious. Talk with your doctor right away if you experience any of the following signs of infection:

• A fever (temperature of 101 degrees Fahrenheit or higher)
  
  
• Chills or sweating
  
  
• A sore throat or sores in the mouth
  
  
• Abdominal pain
  
  
• Diarrhea or sores around the anus
  
  
• Pain or burning when urinating or frequent urination
  
  
• A cough or breathlessness
  
  
• Any redness, swelling, or pain, especially around a cut, wound, or an intravenous (IV) catheter site
  
  
• Unusual vaginal discharge or itching

Management and treatment

Depending on the type or dose of chemotherapy, neutrophil counts generally start to drop about a week after each round of chemotherapy begins and usually reach a low point (called the nadir) about seven to 14 days after treatment. A person is most vulnerable to infection at this point. The number of neutrophils then starts to rise again as the bone marrow resumes normal production of neutrophils, however; it may take three to four weeks to reach a normal level. When the neutrophil level returns to normal, another round of chemotherapy can begin. If the patient develops neutropenia or the neutrophil level does not return to normal quickly enough, the doctor may delay the next round of chemotherapy or recommend a lower dose. Sometimes the doctor will recommend antibiotics during periods of prolonged neutropenia to try to prevent infections from occurring.

If chemotherapy causes neutropenia with a fever, the doctor may decide to use medications called white blood growth factors during subsequent cycles of chemotherapy. These include filgrastim (Neupogen), pegfilgrastim (Neulasta), or sargramostim (Leukine or Prokine). These drugs help the body make more neutrophils or other types of white blood cells. Read what to know about the American Society of Clinical Oncology’s (ASCO’s) guideline on white blood cell growth factors.

More Information

Infection

Managing Side Effects

Additional Resources

Cancersymptoms.org: Neutropenia