Low white blood cell count (neutropenia)

Neutropenia and leukopenia are terms used to refer to lowered numbers of white blood cells (WBCs) in the blood. WBCs help the body fight infection and disease. When WBC counts are low, there is a higher risk of infection. Not every person receiving cancer treatment will experience neutropenia or leukopenia, but many do.

Leukopenia is a decrease in the total number of white blood cells. Leukocyte is another name for white blood cell. They are made in the bone marrow and are found in the blood and lymphatic tissues. Leukocytes play a key part in defending the body against viruses and bacteria, which can cause infection.

Neutropenia is a low neutrophil count. Neutrophils are a type of WBC that surround and destroy bacteria in the body. They are very important in fighting infection.

Normal levels of WBCs may vary between labs. The neutrophil count may be reported as the absolute neutrophil count (ANC). Generally, normal ranges are:

• WBC (leukocyte) count: 4.5–11.0 x 10⁹/L
• neutrophil count: 3–7 x 10⁹/L

A person has leukopenia when the total WBC count is less than 3.0 x 10⁹/L. A person has neutropenia when the ANC is less than 1.9 x 10⁹/L. The neutrophil count usually decreases with the WBC count, but it is possible to have a normal WBC count and still have neutropenia.

The risk of developing an infection is greater when the ANC is less than 1.5 x 10⁹/L. The risk increases as the neutrophil level drops and the longer it remains low. An infection is likely to occur if the ANC is less than 0.5 x 10⁹/L.

Once the WBC count drops, it remains low for 7–10 days. The lowest level that blood cell counts reach is called the nadir. During nadir, the body’s resistance to infection is weakest. It is important to do everything possible to lower the chances of infection and to seek immediate treatment even if you think you have an infection.

Leukopenia and neutropenia can be caused by:

• chemotherapy
• radiation therapy
• certain biological therapies such as interleukin-2 (Aldesleukin, Proleukin) or rituximab (Rituxan)
• bone marrow disease such as leukemia

The risk of low white blood cell counts is greater if chemotherapy and radiation therapy are given at the same time or if large areas of bone marrow are in the radiation treatment area.

Leukopenia and neutropenia do not cause any symptoms. People with cancer usually find out they have low white blood cell counts from a blood test or when they get an infection. An infection can start in almost any part of the body, but many occur in the skin, mucous membranes, digestive tract or respiratory tract.

The most common signs and symptoms of an infection include:

• fever and chills
• swelling and redness
• mouth sores, red or white patches in the mouth
• sore throat
• severe cough or shortness of breath
• pain or burning when urinating or foul-smelling urine
• diarrhea
• pain, redness or swelling of the rectal area
• drainage, pus, redness or swelling from a cut, sore, incision, venous access device or drainage tube
• unusual vaginal discharge or itching

Sometimes a fever is the only sign of infection, but a person can have an infection without having a fever or chills. Take the temperature by mouth or under the arm. You can also use a special ear thermometer to take the temperature. Do not take a rectal temperature because this could cause bleeding or an infection in the rectal area.

Leukopenia or neutropenia are usually diagnosed by a complete blood count (CBC). You may also need to have bone marrow aspiration and biopsy to find the cause of leukopenia or neutropenia.

If the healthcare team thinks you have an infection, they will:

• ask you about symptoms, medicines and treatments
• do a physical exam
• take your temperature

They will also order blood or urine tests or collect samples from any other possible site of infection. Samples are sent to a laboratory for culture and sensitivity (C&S) tests. C&S tests determine the type of micro-organism causing the infection (bacteria, viruses, fungi, protozoa or parasites). Knowing the cause of an infection helps the healthcare team decide on the best treatment option.

Your healthcare team may order a chest x-ray if they think you have pneumonia. They may also order other imaging tests based on your health history and physical exam.

The healthcare team may recommend measures to reduce the effect of cancer treatments on white blood cell counts.

The following medicines may help increase WBC counts. They can also help lower the risk of or treat infection.

Colony-stimulating factors are special medicines called growth factors. They stimulate, or help, the bone marrow to make white blood cells, red blood cells and platelets. Different types of growth factors stimulate the bone marrow to make different types of blood cells. Granulocyte colony-stimulating factors (G-CSFs) stimulate the bone marrow to make granulocytes. Granulocyte-macrophage colony-stimulating factors (GM-CSFs) stimulate the bone marrow to make granulocytes and macrophages. Granulocytes and macrophages are types of WBCs.

With some chemotherapy drugs, G-CSFs or GM-CSFs may be given to stimulate the bone marrow to produce more WBCs. Filgrastim (Neupogen) and pegfilgrastim (Neulasta) are examples of G-CSFs. Sargramostim (Leukine) is a GM-CSF that may be used to help reduce the chance of developing infection and keep chemotherapy on schedule.

Antibiotics are drugs that fight infections caused by bacteria and other micro-organisms. The healthcare team may prescribe antibiotics if your white blood cell count is too low, the risk of infection is high or they suspect you have an infection. Other infection-fighting drugs, such as antiviral or antifungal drugs, may also be given. Antibiotics, antiviral or antifungal drugs are given by mouth (orally) or intravenously.

The healthcare team will choose medicines based on the type of organism causing the infection. Until lab reports identify the organism, you may be given an antibiotic that fights many kinds of bacteria. This type of drug is called a broad spectrum antibiotic.

Some people may have to be admitted to the hospital if their absolute neutrophil count (ANC) is too low. Special precautions are taken until the neutrophil count is 0.5 or higher and your body can fight infection again. You may not be allowed to have visitors. If you can have visitors, they may have to wash their hands and wear a protective mask or gown. Anyone who feels unwell and those who have been exposed to an infectious disease (such as chickenpox or measles) should not visit.

If the white blood cell count or ANC is too low, chemotherapy is sometimes stopped temporarily. Sometimes a lower dose of chemotherapy drugs is given to lessen the impact on white blood cell counts and reduce the risk of further delays in treatment.

Report any symptoms of infection to your doctor or healthcare team. Do not take any medicines for a fever without checking first with the healthcare team.

You can also take the following steps to help lower your risk of getting an infection.

This is one of the most effective ways of avoiding infection. Wash your hands often during the day, especially before eating and after going to the bathroom. Carry a small bottle of hand sanitizer to clean your hands if a sink is not available. Clean the anal area gently but thoroughly after a bowel movement.

Take a warm, instead of hot, shower every day. Hot showers can dry out the skin. Gently pat skin dry rather than rubbing it briskly.

Use a soft toothbrush or clean cloth to clean teeth and gums to avoid irritating the mouth.

Use pads rather than tampons during menstruation.

If your skin becomes dry or cracked, use moisturizing lotions to soften it and help it heal. The healthcare team or pharmacist can suggest lotions.

Wear rubber gloves when doing dishes, cleaning or gardening. Use cuticle cream or cuticle remover instead of tearing or cutting the cuticles. Do not squeeze or scratch pimples. Use an electric shaver instead of a razor to avoid cutting the skin. Be especially careful to avoid burns when ironing or cooking. Clean any cut or scrape at once with warm water and soap.

Whenever possible, get enough rest, eat a well-balanced diet, drink plenty of fluids and get regular exercise.

If you have low blood cell counts, take steps to protect yourself. Stay away from anyone who has a cold, the flu or an infectious disease like chicken pox, mumps, measles or shingles. Talk to the healthcare team about vaccinations. Depending on the type of cancer treatment, some vaccinations should be given while others should be avoided. Avoid contact with anyone who has been recently immunized with live virus vaccines, such as those for chicken pox, polio or measles. Avoid crowds, such as those in shopping malls or on buses while blood counts are low.

Follow precautions for food safety. Cook vegetables and wash and peel fruit to get rid of bacteria on their surfaces. Avoid uncooked eggs, raw or undercooked meats, poultry, fish and seafood. These foods can contain harmful organisms.

Live plants can be a source of germs. Remove plants from the living area. Avoid cleaning cat litter boxes or birdcages.

Check with the healthcare team if any precautions should be taken during sexual activity when white blood cell counts are low.