White blood cells, or leukocytes, are vital components of a child's immune system and play a major role in fighting infection. Leukopenia, the medical term used for abnormally low numbers of white blood cells, can have numerous causes, including disease, medications, infection and cancer therapy. Very low white blood cell counts increase a child's susceptibility to infection and must be managed appropriately.
Types
Total white blood cell counts measure the numbers of five different types of white blood cells including neutrophils, eosinophils, basophils, lymphocytes and monocytes. Low total WBC counts are typically due to reduced numbers of infection-fighting neutrophils. According to Dr. George R. Buchanan of the Children's Medical Center Dallas, total WBC count and absolute neutrophil count are the two most important measures for physicians to assess.
Low Values
Dr. Buchanan claims that during infancy and early childhood, WBC counts greater than 4500 cells per cubic millimeter of blood and ANCs above 1000 per cubic millimeter of blood are considered normal. WBC deficiency is described as mild when total WBC counts are between 3000 and 4500 cells and ANCs are between 500 to 1000 cells. Total WBC counts ranging from 1500 to 3000 and ANCs ranging from 200 to 500 cells indicate moderate leukopenia. WBC deficiency is severe when total WBC counts are below 1500 and ANCs are below 200.
Causes
Dr. Buchanan lists infection, race and drug exposure as common causes of mild to moderate leukopenia in children. He reports that the condition is often found in normal children who have or have recently recovered from a viral infection. Leukopenia is also a common occurrence in perfectly healthy African-American children. According to Buchanan, medications such as anticonvulsants and psychotropic drugs for depression may cause moderate reductions in WBC numbers. Seattle Children's Hospital lists bone marrow conditions, such as aplastic anemia in which the bone marrow fails to produce blood cells, and white blood cell destruction, as occurs with cancer therapy, as causes for severe leukopenia.
Symptoms
Low WBC counts increase a child's risk of infection. Frequent and uncommon infections are often the only symptom of leukopenia. According to Seattle Children's Hospital, infections may occur in the mouth, throat, lungs, sinuses and skin, and are accompanied by fever. Symptoms such as pallor, bruising and an enlarged liver or spleen may also occur. Additional tests, such as a biopsy to assess bone marrow function, may be required to accurately diagnose the cause of low WBC counts.
Management
Dr. Buchanan reports that mild leukopenia without evidence of disease should be monitored annually. If low WBC counts persist and the child remains healthy, no further testing is required. Children with severe leukopenia need careful monitoring. Children's Mercy Hospital in St. Louis , Missouri, recommends a child with ANCs less than 500 per cubic millimeter or less than 1000 and falling not attend school or other functions that may expose them to sick people. Have the child wear a mask when outside or visiting the physician or hospital. Check the child's temperature twice daily and notify a health care professional of any fever over 101.5 degrees. Examine the child's skin and mouth regularly for any sign of infection and be diligent about hand washing.
