Leukocytes are another name for white blood cells (WBCs). They play a key part in defending the body against viruses and bacteria, which can cause infection. Neutrophils are one type of white blood cell that surround and destroy bacteria in the body and are very important in fighting infection.
Leukopenia is a decrease in the total number of white blood cells. Low neutrophil counts (neutropenia) can develop if too many neutrophils are destroyed before the bone marrow has had a chance to replace them. When WBCs, especially neutrophils, are decreased, a person has an increased risk for developing an infection.
The normal value for:
- white blood cell count is 4.5–11.0 x 109 /L
- neutrophils may be reported as absolute neutrophil count (ANC) and is 3–7 x 109 /L
- these values may vary from laboratory to laboratory
A person has leukopenia when their total WBC is less than 3.0 x 109 /L. The neutrophils usually decrease with the WBC count, but it is possible for a person to have a normal total WBC count and still be neutropenic.
A person has neutropenia when their ANC is less than 1.5 x 109 /L. Their risk of developing infection is increased when the ANC is less than this level. Risk increases as the level drops and the longer it remains low. An infection is more likely to occur if the ANC is less than 0.5.
Causes
- Many drugs used during chemotherapy affect white blood cells in the bone marrow.
- Bone marrow suppression (myelosuppression) can also occur after radiation on the bone marrow. This is related to the amount of marrow in the radiation treatment area.
- Low white blood cell counts are more likely to happen if the person is receiving chemotherapy and radiation therapy at the same time.
- Some biological therapies, such as aldesleukin (Proleukin, Interleukin-2) or rituximab (Rituxan).
Symptoms
The most common sign of infection is a fever. However, a person can also have an infection and not have a fever. Other signs of infection, such as swelling and redness, can also be absent. An infection can start in almost any part of the body, but many occur in skin and mucous membranes or the digestive or respiratory tract.
Notify the doctor or healthcare team if any of the following signs of infection occur:
- a fever over 38°C (100°F)
- sometimes fever is the only sign of infection
- unusual sweating or chills
- 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
Diagnosis
Infection and neutropenia is usually diagnosed by:
Specimens from blood, urine or any other possible site of infection are obtained and sent for culture when an infection is suspected. Imaging studies, such as a chest x-ray, may be done if pneumonia is suspected during the history and physical examination. Other imaging tests may be done based on clinical findings.
An infection can be caused by many types of micro-organisms, such as bacteria, viruses, fungi, protozoa or parasites. Bacteria are the most common type of infection-causing organism.
Management
Measures can be taken to help prevent infection:
- Wash hands often during the day, especially before eating and after going to the bathroom. Carry a small bottle of hand sanitizer to clean hands if a sink is not available.
- Take a warm shower every day instead of a hot shower that will dry out the skin. Gently pat skin dry rather than rubbing it briskly.
- Use moisturizing lotions if skin becomes dry or cracked to soften it and help it heal. The healthcare team or pharmacist can suggest one.
- Do not squeeze or scratch pimples.
- Use cuticle cream or cuticle remover instead of tearing or cutting the cuticles.
- Wear rubber gloves when doing dishes, cleaning or gardening.
- Avoid cuts to skin during shaving by using an electric shaver instead of a razor.
- Clean any cut or scrape at once with warm water and soap.
- Be especially careful not to burn yourself when ironing or cooking.
- Use a soft toothbrush or clean cloth to clean teeth and gums to avoid irritating the mouth.
- Clean the anal area gently but thoroughly after a bowel movement.
- Use pads if menstruating rather than tampons.
- Remove live plants from the living area, which can be a source of germs.
- Follow precautions for food safety. Cook vegetables, wash and peel fruit. Avoid uncooked eggs; raw or undercooked meats, poultry and fish salads. Vegetables and fruit can harbour bacteria on their surfaces. Raw or undercooked meats or poultry can contain harmful organisms.
- Talk to your healthcare team about vaccinations. Depending on your treatment, there may be some vaccinations you should avoid and others you should have.
- Avoid crowds, such as those in shopping malls or on buses while blood counts are low.
- Stay away from anyone who has a cold, the flu or an infectious disease like chicken pox, mumps, measles, or shingles.
- Avoid contact with children who have been recently immunized with “live virus” vaccines such as chicken pox, polio or measles.
- Avoid cleaning cat litter boxes or birdcages.
- Check with the healthcare team about restrictions on sexual activity when white blood cell counts are low.
- Report any signs of infection to the doctor or healthcare team. Do not take any medications for a fever without checking first with the healthcare team.
Other measures can be taken to reduce the chance of infection or to reduce the effect of cancer treatments on white blood cell counts.
Medications
Medications may be used to increase white blood cell counts, to prevent infection or treat infections.
Colony-stimulating factors
The healthcare team may order a special drug to help neutrophil counts return to normal levels. Granulocyte colony-stimulating factors (G-CSFs) stimulate the bone marrow to produce white blood cells, particularly granulocytes (neutrophils). Filgrastim (Neupogen) and pegfilgrastim (Neulasta) are two colony-stimulating factors that are used to help reduce the chance of developing infection and keep chemotherapy on schedule.
Colony-stimulating factors like filgrastim are often given daily, usually by subcutaneous injection. They may be started a day or two after chemotherapy and used for up to 2 weeks or until the ANC has improved. Pegfilgrastim is given once during a chemotherapy cycle instead of daily.
Antibiotics
A drug to fight infections (antibiotic) may be ordered if the white blood cell count becomes too low and the healthcare team feels the risk for developing an infection is high or if an infection is suspected. The practice of giving antibiotics to prevent an infection is called prophylaxis. Antibiotics or other infection-fighting drugs (such as antiviral or antifungal drugs) may be given by mouth (orally) or intravenously.
Medications used to treat infections are often selected based on the type of organism causing the problem. Until culture reports come back from the laboratory, which identify the organism, an antibiotic that fights many kinds of bacteria (broad spectrum antibiotic) may be started.
If an infection is severe enough, it can lead to a condition called septic shock.
Special precautions
Sometimes a person may have to be admitted to the hospital and special precautions are taken until the neutrophil count is 0.5 or higher and the body is able to fight infection. Visitors may be restricted, have to wash their hands and may have to wear a protective mask or gown when visiting. Anyone who feels unwell and children exposed to an infectious disease (such as chickenpox or measles) should not visit.
If the white blood cell count becomes too low, cancer treatments may be delayed for a short period of time. Chemotherapy drugs are sometimes stopped temporarily if the WBC count is low or the ANC is low. Sometimes a lower dose of chemotherapy drug will be given to lessen the impact on white blood cell counts and reduce the risk of further delays in treatment.