What is the appropriate antibiotic therapy for a patient with leukocytosis and neutrophilia?

Management of Leukocytosis with Neutrophilia (WBC 11.9, Neutrophil abs 9722)

Empirical broad-spectrum antimicrobial therapy is mandatory for patients with neutrophilia who are febrile and profoundly neutropenic. 1

Assessment of Leukocytosis and Neutrophilia

• Leukocytosis (WBC 11.9) with neutrophilia (neutrophil count 9722) is a common sign of bacterial infection and should prompt identification of other signs and symptoms of infection 2
• Evaluate for potential causes including:
  • Bacterial infections (most common cause) 1
  • Stress response (surgery, trauma, emotional stress) 2
  • Medications (particularly corticosteroids) 2
  • Chronic inflammatory conditions 2
  • Hematologic malignancies 2
  • Thrombosis (neutrophilia is commonly observed in patients with thrombotic events) 3

Antibiotic Management

For Febrile Neutropenic Patients:

• Initiate empirical broad-spectrum antimicrobial therapy immediately for febrile patients with neutropenia 1
• First-line options include:
  • Levofloxacin 500mg orally daily (or equivalent fluoroquinolone) 1, 4
  • Ciprofloxacin 500mg orally twice daily 1
  • For more severe cases: ceftazidime, meropenem, or other broad-spectrum IV antibiotics 1

For High-Risk Patients with Prolonged Neutropenia:

• Fluoroquinolone prophylaxis should be considered for patients with expected durations of prolonged and profound neutropenia (ANC <100 cells/mm³ for >7 days) 1
• Levofloxacin is preferred in situations with increased risk for oral mucositis-related invasive viridans group streptococcal infection 1

Monitoring and Follow-Up

• Daily assessment of fever trends, bone marrow and renal function is indicated until the patient is afebrile and ANC ≥ 0.5 × 10⁹/l 1
• If still pyrexial at 48 hours:
  • If clinically stable: continue initial antibacterial therapy 1
  • If clinically unstable: rotate antibacterial therapy or broaden coverage 1
• When pyrexia lasts for >4–6 days, consider initiation of antifungal therapy 1

Additional Supportive Care

• Consider granulocyte colony-stimulating factor (G-CSF; filgrastim) to reduce the incidence of myelosuppression and infections in patients with severe neutropenia 1
• For patients with platelet counts lower or equal to 10 × 10⁹/L, provide platelet transfusions 1
• For platelet counts between 10 and 20 × 10⁹/L, administer platelet transfusions in cases of fever and/or infection 1
• Maintain hemoglobin levels ≥7.0 g/dL through packed red blood cell transfusions as needed 1

Special Considerations

• If active infection is present, attempt to control infection before instituting intensive therapy regimens 1
• For patients with persistent fever despite neutrophil recovery, consider antifungal therapy 1
• In patients with pneumonia, extend antibiotic coverage to treat atypical organisms by adding a macrolide antibiotic to a β-lactam antibiotic 1

Prognosis

• Leukocytosis and neutrophilia are associated with higher mortality rates in certain conditions, particularly in patients with neoplasia 5, 6
• Patients with neutrophilia related to infection generally have better outcomes than those with neutrophilia due to malignancy 5

Remember that the appropriate management depends on the underlying cause of the leukocytosis and neutrophilia, with bacterial infection being the most common etiology requiring prompt antimicrobial therapy.