What is the management for a patient with leukocytosis and elevated neutrophil count?

Management of Leukocytosis with Elevated Neutrophil Count

Leukocytosis (WBC 14.8) with neutrophilia (11) strongly suggests a bacterial infection and requires prompt initiation of empiric antimicrobial therapy after appropriate cultures are obtained. 1

Assessment and Diagnosis

• Definition: The patient's values show leukocytosis (WBC >14,000 cells/mm³) with neutrophilia, indicating high likelihood of bacterial infection
• Likelihood of bacterial infection:
  • Elevated WBC >14,000 cells/mm³ has a likelihood ratio of 3.7 for bacterial infection 1
  • Neutrophil percentage >90% has a likelihood ratio of 7.5 for bacterial infection 1
  • The presence of both significantly increases probability of bacterial infection

Initial Management Steps

1. Obtain cultures before starting antibiotics:

   • Blood cultures (2 sets from different sites)
   • Urine culture
   • Sputum culture if respiratory symptoms present
   • Site-specific cultures based on clinical presentation

2. Initiate empiric antimicrobial therapy:

   • For non-neutropenic patients (ANC >1000/mm³): Broad-spectrum antibiotics targeting likely sources based on clinical presentation
   • For neutropenic patients (ANC <1000/mm³): More aggressive approach required 2

3. Identify and address the source of infection:

   • Focused physical examination for localized signs of infection
   • Imaging studies as indicated by symptoms (chest X-ray, CT scan, etc.)

Specific Management Based on Neutrophil Count

If ANC >1000/mm³ (Non-neutropenic):

• Target antibiotics to the most likely source of infection
• Monitor response with daily WBC counts and clinical assessment
• Adjust therapy based on culture results when available

If ANC <1000/mm³ (Neutropenic):

• Febrile neutropenia protocol:
  • Immediate broad-spectrum antibiotics (e.g., antipseudomonal β-lactam) 2
  • Consider adding an aminoglycoside for septic shock or suspected resistant organisms
  • Reassess at 48 hours 2:
    • If afebrile and improving: Continue current regimen
    • If still febrile but stable: Continue current regimen
    • If deteriorating: Broaden coverage or add antifungal therapy

Additional Considerations

• Granulocyte colony-stimulating factors (G-CSF):

  • Consider in high-risk patients with neutropenia 2
  • Can reduce duration of neutropenia and risk of infectious complications
  • Initiate when ANC <0.5 × 10⁹/L 2

• Antibiotic prophylaxis:

  • Consider fluoroquinolone prophylaxis in prolonged, profound neutropenia (ANC <100/mm³ for >2 weeks) 2
  • Antifungal prophylaxis may be indicated in prolonged neutropenia 2

Monitoring and Follow-up

• Daily CBC with differential to track WBC and neutrophil counts
• Daily assessment of fever trends and clinical status
• Adjust antibiotics based on culture results and clinical response
• Continue antibiotics until:
  • If neutrophil count ≥0.5 × 10⁹/L, patient is afebrile for 48 hours, and cultures are negative 2
  • If neutrophil count <0.5 × 10⁹/L but patient has been afebrile for 5-7 days without complications 2

Common Pitfalls to Avoid

• Don't delay antibiotics while waiting for culture results in suspected serious infection
• Don't dismiss leukocytosis without fever, as bacterial infection can present without fever, especially in elderly or immunocompromised patients 1
• Don't overlook non-infectious causes of leukocytosis (medications, stress, inflammation)
• Don't continue broad-spectrum antibiotics unnecessarily once a pathogen is identified and susceptibilities are known

By following this algorithmic approach to leukocytosis with neutrophilia, you can effectively identify and treat the underlying cause while minimizing complications and optimizing outcomes.