From the Guidelines
Low white blood cell (WBC) and neutrophil counts, known as leukopenia and neutropenia respectively, require immediate medical attention as they indicate a weakened immune system, and the most recent and highest quality study suggests that granulocyte colony-stimulating factor (G-CSF) medications like filgrastim may be necessary for treatment 1. If you have these conditions, contact your healthcare provider promptly for evaluation, especially if you have symptoms like fever, chills, or recurrent infections. The normal WBC count ranges from 4,500-11,000 cells/μL, with neutrophils typically comprising 40-60% of total WBCs. Causes include viral infections, certain medications (chemotherapy, antibiotics like trimethoprim-sulfamethoxazole), autoimmune disorders, bone marrow disorders, nutritional deficiencies (vitamin B12, folate), and genetic conditions. Some key points to consider include:
- The risk of infection increases with the depth and duration of neutropenia, with the greatest risk occurring in patients who experience profound, prolonged neutropenia after chemotherapy 1.
- The frequency and severity of infection are inversely proportional to the neutrophil count; the risks of severe infection and bloodstream infection are greatest when the neutrophil count is less than 100/mcL 1.
- Treatment depends on the underlying cause and severity, and may involve G-CSF medications, antibiotics for infections, or adjusting medications that may be causing the condition 1. While waiting for medical care, practice good hygiene, avoid crowds and sick people, maintain proper nutrition with adequate protein and vitamins, and watch for signs of infection. The body needs adequate white blood cells, particularly neutrophils, to fight bacterial and fungal infections, so addressing low counts is essential for maintaining immune function. In terms of specific treatment, G-CSF medications like filgrastim may be necessary to reduce the risk of bacterial infections, including pneumonia, in patients with depressed absolute neutrophil counts due to HIV disease or drug therapy 1. It is also important to note that the use of G-CSF or GM-CSF to prevent bacterial infections in HIV-infected patients with neutropenia cannot be recommended without careful consideration of the individual patient's circumstances 1.
From the Research
Definition and Causes of Low WBC and Neutrophil
- Low WBC (white blood cell) count, also known as leukopenia, can be caused by a significant reduction in neutrophils, which comprise 50% to 70% of circulating leukocytes 2.
- Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1,500/mcL 2, 3.
- Causes of neutropenia can be intrinsic, such as impaired proliferation and maturation of myeloid progenitor cells in the bone marrow, or extrinsic, such as drug-induced neutropenia 4, 2.
Diagnosis and Treatment of Neutropenia
- Assessment of patients with neutropenia should be guided by the severity on presentation, duration of leukopenia, and clinical status of the patient 2.
- Patients with febrile neutropenia should undergo treatment with antibiotics, and other treatments are aimed at management of the underlying cause of neutropenia 2, 5.
- Severe chronic neutropenia can be treated with granulocyte colony-stimulating factor (G-CSF), and novel treatments such as neutrophil elastase inhibitors, SGLT-2 inhibitors, and gene therapy are under investigation 3, 6.
Management of Neutropenia
- Patients with acute febrile neutropenia should be treated with antibiotics, and those at high risk of severe neutropenia should be treated prophylactically with G-CSF 3.
- The use of prophylactic antibiotics in patients with neutropenia is associated with risks and has limited mortality benefit, and early de-escalation or discontinuation may be safe in many patients 5.
- A stepwise approach to neutropenia, focusing on reaching a provisional diagnosis and treatment plan, can help guide management 3.