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

Management of Leukocytosis with Neutrophilia (WBC 11.5, neutrophils 8.8, lymph % 16.7)

The appropriate management for a patient with leukocytosis and neutrophilia requires prompt evaluation for infection, which is the most common cause, followed by empiric antibiotic therapy if infection is suspected based on clinical presentation. 1

Initial Assessment

• Evaluate for signs and symptoms of infection, as leukocytosis with neutrophilia is a common indicator of bacterial infection 1, 2
• Check for potential sources of infection including respiratory, gastrointestinal, urinary tract, skin, perineal region, oropharynx, and central nervous system 3
• Assess for other non-infectious causes of leukocytosis including:
  • Stress-induced causes: surgery, trauma, exercise, emotional stress 1
  • Medications that can cause leukocytosis 1
  • Chronic inflammatory conditions 1
  • Smoking and obesity 1
  • Hematologic malignancies (look for fever, weight loss, bruising, fatigue) 1, 4

Diagnostic Workup

• Obtain blood cultures (minimum of two sets) including cultures from any indwelling IV catheters before starting antibiotics 3, 5
• Order appropriate cultures based on suspected infection focus (urine, sputum, stool, skin lesions) 3
• Perform additional laboratory tests:
  • Complete blood count with peripheral smear to evaluate types and maturity of white blood cells 1, 4
  • Renal and liver function tests 3
  • C-reactive protein 3, 2
  • Coagulation screen 3
• Obtain chest radiograph if respiratory symptoms are present 3

Management Algorithm

For Patients with Suspected Infection:

1. If neutrophil count ≤0.5 × 10⁹/L (neutropenic fever):

   • Initiate empiric antibiotic therapy promptly 5
   • Choose one of the following agents: cefepime, ceftazidime, imipenem, or meropenem 5
   • Add vancomycin only if specific criteria are met (suspected catheter-related infection, known colonization with resistant gram-positive organisms) 5

2. If neutrophil count >0.5 × 10⁹/L with signs of infection:

   • Start appropriate empiric antibiotics based on the suspected source of infection 3, 5
   • For patients with severe sepsis or septic shock, use broad-spectrum antibiotics covering gram-negative and gram-positive organisms 3

3. Follow-up assessment at 48 hours:

   • If afebrile and clinically improved: continue current antibiotics 3
   • If still febrile but clinically stable: continue initial antibacterial therapy 3
   • If clinically unstable: broaden antimicrobial coverage and seek advice from an infectious disease specialist 3, 5

4. Duration of therapy:

   • If neutrophil count ≥0.5 × 10⁹/L, patient is asymptomatic, afebrile for 48 hours, and blood cultures are negative: discontinue antibiotics 3, 5
   • If neutrophil count <0.5 × 10⁹/L but patient has been afebrile for 5-7 days without complications: consider discontinuing antibiotics except in high-risk cases 3, 5
   • If fever persists beyond 4-6 days: consider antifungal therapy 3, 5

For Patients Without Evidence of Infection:

• Monitor complete blood count 6
• Investigate for non-infectious causes of leukocytosis 1
• If malignancy is suspected (persistent unexplained leukocytosis, abnormal cell morphology on peripheral smear), refer to a hematologist/oncologist 1, 4

Special Considerations

• Leukocytosis can occur in thrombotic conditions, so evaluate for possible thrombosis if infection is not evident 7
• Deep eosinopenia (marked decrease in eosinophil count) has a specificity of 94% for diagnosing infection 2
• When monitoring neutrophilic patients, the total WBC count is nearly as effective as the neutrophil count for detecting recovery, making repeated differential counts often unnecessary 6