What is the recommended treatment for a patient presenting with fever, cough, and rhinitis, with a blood count showing leukocytosis (elevated white blood cell count), neutrophilia (elevated neutrophil count), and lymphopenia (low lymphocyte count)?

Treatment of Acute Bacterial Respiratory Infection with Neutrophilic Leukocytosis

Based on the clinical presentation of fever, cough, rhinitis with marked leukocytosis (13,900/μL), severe neutrophilia (89%), and lymphopenia (9%), this patient requires immediate empirical antibiotic therapy targeting community-acquired bacterial respiratory pathogens, specifically with a respiratory fluoroquinolone (levofloxacin or moxifloxacin) or azithromycin combined with a beta-lactam.

Immediate Risk Assessment

The laboratory pattern strongly suggests acute bacterial infection rather than viral illness:

• Neutrophilia >80% with leukocytosis is highly specific for bacterial infection and warrants immediate antibiotic initiation 1
• Lymphopenia (9%) combined with neutrophilia creates a clinical picture consistent with severe bacterial respiratory infection 2
• This pattern (leukocytosis with neutrophilia and lymphopenia) has 98.4% correlation with elevated C-reactive protein in bacteremic patients, indicating significant bacterial infection 2

Critical pitfall to avoid: Do not delay antibiotic therapy while awaiting cultures in patients with this laboratory pattern, as neutrophilia >80% strongly predicts bacterial etiology 1

Empirical Antibiotic Selection Algorithm

First-Line Therapy (Choose ONE):

Option 1 - Respiratory Fluoroquinolone Monotherapy:

• Levofloxacin 750 mg PO daily OR moxifloxacin 400 mg PO daily 1, 3
• Provides coverage for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and atypical pathogens 4

Option 2 - Combination Therapy:

• Azithromycin 500 mg PO on day 1, then 250 mg daily for 4 days PLUS
• Amoxicillin-clavulanate 875 mg PO twice daily 4

When to Choose Each Option:

• Use fluoroquinolone monotherapy if: Patient has recent beta-lactam exposure, penicillin allergy, or suspected atypical pathogen (Mycoplasma, Chlamydophila) 3, 4
• Use combination therapy if: No recent fluoroquinolone use, allowing preservation of fluoroquinolones for potential future neutropenic fever episodes 1

Special Considerations for This Laboratory Pattern

Neutrophilia Management:

The 89% neutrophil count indicates active bacterial infection but does NOT require growth factor support (G-CSF), as the absolute neutrophil count is elevated, not decreased 1, 3

Key distinction: This patient has neutrophilia (elevated neutrophils) from infection response, NOT neutropenia (low neutrophils) requiring growth factor therapy 1

Monitoring Parameters:

• Daily temperature monitoring until afebrile for 48 hours 3
• Repeat CBC in 48-72 hours to assess for:
  • Declining leukocyte count (indicates treatment response) 1
  • Rising lymphocyte percentage (indicates recovery) 2
  • Persistent or worsening leukocytosis (suggests treatment failure or complications) 3

Duration of Therapy

• Minimum 5 days of antibiotics for community-acquired respiratory infection 4
• Continue until afebrile for 48 hours AND clinical improvement (reduced cough, improved respiratory symptoms) 3
• Typical total duration: 5-7 days for uncomplicated bacterial respiratory infection 4

Red Flags Requiring Hospitalization

Reassess for these features that would mandate inpatient management:

• Respiratory rate >24 breaths/min or oxygen saturation <92% on room air 1
• Systolic blood pressure <90 mmHg or signs of sepsis 1
• Mental status changes or inability to maintain oral intake 1
• WBC >15,000/μL or <4,000/μL (this patient's 13,900 is borderline but acceptable for outpatient management if clinically stable) 2

Critical Warnings About Azithromycin

If azithromycin is selected, counsel patient about:

• QT prolongation risk: Avoid in patients with known QT prolongation, bradycardia, or concurrent use of other QT-prolonging drugs 4
• Hepatotoxicity: Discontinue immediately if jaundice or hepatitis symptoms develop 4
• Clostridium difficile risk: Advise patient to report severe diarrhea immediately 4

When to Reassess

Return immediately if:

• Fever persists beyond 72 hours of antibiotic therapy 3
• Worsening respiratory symptoms (increased dyspnea, chest pain, hemoptysis) 1
• Development of rash, severe diarrhea, or new symptoms 4

Routine follow-up in 5-7 days to confirm clinical resolution and review any culture results if obtained 3