Management of Leukopenia (Low White Blood Cell Count)
The management of leukopenia should focus on identifying and treating the underlying cause while providing appropriate supportive care based on the severity and clinical presentation of the patient. 1, 2
Diagnostic Approach
- Evaluate previous blood counts to understand the pattern and duration of leukopenia (acute vs. chronic) 2
- Examine complete blood count to determine if leukopenia is isolated or part of bi/pancytopenia, which suggests bone marrow involvement 2
- Perform manual peripheral blood smear to assess specific white blood cell populations and identify potential causes such as dysplasia 2
- Consider bone marrow examination in cases of persistent unexplained leukopenia or when malignancy is suspected 1
Common Causes of Leukopenia
- Infections: Viral (most common), bacterial, fungal, or parasitic 1
- Medications: Chemotherapy, antibiotics, antipsychotics, immunosuppressants 1
- Hematologic disorders: Leukemia, myelodysplastic syndromes 1
- Nutritional deficiencies: Vitamin B12, folate (megaloblastosis) 1
- Hypersplenism: Increased destruction of white blood cells 1
- Autoimmune disorders: Immune-mediated neutropenia 1
- Congenital/hereditary causes: Rare genetic disorders 1
Management Based on Severity
Severe Neutropenia (ANC < 500/mcL) with Fever
- Immediate hospitalization for patients with febrile neutropenia 2
- Prompt initiation of broad-spectrum antibiotics without waiting for culture results 2
- Blood cultures and other appropriate cultures before starting antibiotics 3
- Avoid invasive procedures such as central venous catheterization, lumbar puncture, and bronchoscopy due to high risk of hemorrhagic complications 3
Management of Neutropenia in Specific Contexts
Chemotherapy-Induced Neutropenia
- Granulocyte colony-stimulating factor (G-CSF) such as filgrastim may be used to:
- Decrease the incidence of infection and febrile neutropenia in patients receiving myelosuppressive chemotherapy 4
- Reduce the time to neutrophil recovery following induction or consolidation chemotherapy for acute myeloid leukemia 4
- Reduce the duration of neutropenia in patients undergoing bone marrow transplantation 4
Acute Promyelocytic Leukemia (APL) with Leukopenia
- Start ATRA (all-trans retinoic acid) immediately upon suspicion of APL diagnosis 3
- Administer lymphodepleting conditioning regardless of WBC count in patients preparing for CAR-T cell therapy 3
- Monitor coagulation parameters closely in APL patients 3
- Maintain platelet counts above 30-50 × 10^9/L and fibrinogen above 100-150 mg/dL 3
Acute Myeloid Leukemia (AML) with Hyperleukocytosis
- Hydroxyurea (50-60 mg/kg/day) to reduce white blood cell counts to less than 10-20 × 10^9/L 3
- Prevention of tumor lysis syndrome with hydration, allopurinol or rasburicase, and urine pH control 3
- Avoid excessive red blood cell transfusions until WBC has been reduced to prevent increased blood viscosity 3
Supportive Care
- Infection prevention measures for severely neutropenic patients 5
- Antimicrobial prophylaxis may be considered in prolonged neutropenia based on institutional protocols 3
- Antifungal prophylaxis with posaconazole has been shown to significantly decrease fungal infections compared to fluconazole in high-risk patients 3
- Avoid azole antifungals during anthracycline chemotherapy due to drug interactions that can increase toxicity 3
Monitoring and Follow-up
- Regular monitoring of blood counts until resolution of leukopenia 2
- Assess for signs and symptoms of infection even in the absence of fever 5
- Consider dilution of blood samples in cases of suspected spurious low WBC counts 6
Special Considerations
- Point-of-care WBC differential testing (e.g., HemoCue WBC DIFF) can provide reliable counts for monitoring leukopenic patients in certain settings 7
- Avoid leukapheresis in APL patients with hyperleukocytosis due to risk of precipitating fatal hemorrhage 3