What is the approach to treating respiratory infections?

Approach to Treating Respiratory Infections

Antibiotics should only be prescribed for respiratory infections with evidence of bacterial etiology or high risk of complications, as many respiratory infections are viral and self-limiting. 1

Diagnostic Assessment

The first step in managing respiratory infections is determining whether the infection is likely viral or bacterial, and whether it's an upper or lower respiratory tract infection:

• Upper Respiratory Tract Infections (URTIs):

  • Most URTIs are viral and do not require antibiotics 1
  • Colored sputum does not indicate bacterial infection but rather inflammatory cells 1
  • Treatment of URTIs with antibiotics will not prevent progression to lower respiratory tract infections 2

• Lower Respiratory Tract Infections (LRTIs):

  • Assess for signs of pneumonia: tachycardia, tachypnea, fever, and abnormal chest examination findings 1
  • Obtain sputum cultures in patients with risk factors for resistant organisms or treatment failure 2

Treatment Algorithm

1. Acute Bronchitis

• Generally viral and self-limiting
• Management:
  • Symptomatic relief only: cough suppressants, expectorants, antihistamines, decongestants 1
  • Antibiotics are NOT recommended for uncomplicated acute bronchitis 1
  • Patient education: Explain that cough typically lasts 2-3 weeks regardless of treatment 1

2. Exacerbation of Chronic Bronchitis

• Antibiotic indications (Anthonisen criteria - need at least 2 of 3):

  • Increased dyspnea
  • Increased sputum volume
  • Increased sputum purulence 2, 1

• Recommended antibiotics:

  • First choice: Amoxicillin (3g/day) for 7-10 days 2, 1
  • Alternatives: Tetracycline, oral cephalosporins, macrolides 2
  • For patients with risk factors for Pseudomonas: Ciprofloxacin or β-lactam with anti-pseudomonal activity 2

3. Community-Acquired Pneumonia (CAP)

• Outpatient treatment:

  • Aminopenicillin (first choice) 2
  • Alternatives: Tetracycline, macrolide, oral cephalosporin 2
  • Treatment duration: 7-10 days for uncomplicated cases; 21 days for L. pneumophila or S. aureus 2, 1

• Hospitalized patients:

  • Moderate CAP: β-lactam plus macrolide or respiratory fluoroquinolone alone 2
  • Severe CAP: Broader spectrum antibiotics based on risk factors 2

4. Sinusitis

• Acute bacterial sinusitis:
  • Treat only when symptoms persist >10 days or worsen after initial improvement 1
  • First-line: Amoxicillin or amoxicillin-clavulanate 3
  • Duration: 10-14 days 2

5. Pharyngitis

• Streptococcal pharyngitis:
  • Confirm with rapid strep test or culture when suspected 2
  • Treatment: Penicillin or amoxicillin for 10 days 2
  • Expected response rate: 80-90% 2

Special Considerations

Antibiotic Selection

• Consider local resistance patterns when selecting antibiotics 1, 4
• High-level penicillin resistance in S. pneumoniae varies geographically (>20% in USA, >50% in some Asian countries) 4
• β-lactamase production in H. influenzae and M. catarrhalis affects treatment choices 4

Risk Factors for Resistant Organisms

• Prior antibiotic use within 3 months
• Prolonged course of disease
• More than four exacerbations per year
• FEV₁ <30% predicted
• Chronic oral steroid use 2

Non-responding Patients

For patients who fail initial therapy:

1. Re-evaluate for non-infectious causes (embolism, cardiac failure)
2. Obtain cultures if not done initially
3. Consider broader spectrum antibiotics covering resistant pathogens 2

Prevention Strategies

• Annual influenza vaccination for high-risk individuals 2
• Pneumococcal vaccination for appropriate populations 2
• Avoid prophylactic antibiotics for COPD/chronic bronchitis 2

Common Pitfalls to Avoid

• Prescribing antibiotics for viral infections (most URTIs, acute bronchitis)
• Failing to recognize bacterial superinfection following viral illness 5
• Not considering local resistance patterns when selecting empiric therapy 4
• Inadequate duration of therapy for confirmed bacterial infections 2
• Not educating patients about expected duration of symptoms, which leads to unnecessary return visits and antibiotic requests 1

When antibiotics are not indicated, clearly explain to patients that their illness is likely viral and self-limiting, discuss the expected duration of symptoms, and emphasize the risks of unnecessary antibiotic use, including increased likelihood of antibiotic-resistant infections 1.