What are the management options for Lower Respiratory Tract Infections (LRTIs)?

Management of Lower Respiratory Tract Infections

For community-acquired LRTIs managed at home, amoxicillin or tetracycline should be the first-line antibiotic choice, with treatment duration of 5-7 days, but antibiotics should only be prescribed when bacterial infection is suspected based on clinical features suggesting pneumonia or purulent exacerbation of chronic bronchitis. 1, 2

Initial Assessment and Triage Decision

The critical first step is determining whether home management is appropriate or hospital referral is necessary 1:

Immediate hospital referral is required if any of the following are present:

• Temperature <35°C or ≥40°C 1
• Heart rate ≥125 beats/min 1
• Respiratory rate ≥30 breaths/min 1
• Blood pressure <90/60 mmHg 1
• Cyanosis, confusion, or drowsiness 1
• Suspected pleural effusion or cavitation 1

Additional factors mandating hospital consideration:

• Age >65 years with comorbidities (COPD, cardiovascular disease, diabetes, chronic liver/renal failure) 1
• Institutionalized patients 1
• Recent hospitalization within previous year 1
• Inability to manage at home due to vomiting, social exclusion, dependency, or altered mental status 1

Antibiotic Decision-Making

Antibiotics are NOT indicated for most LRTIs since many are viral 1. Prescribe antibiotics only when:

• Suspected pneumonia with focal chest signs 1, 2
• Chronic bronchitis exacerbation with ALL three cardinal symptoms: increased dyspnea, increased sputum volume, AND increased sputum purulence 1, 2
• Risk factors for bacterial infection are present 1

First-Line Antibiotic Selection for Outpatient Management

Primary choices 1, 2, 3:

• Amoxicillin (aminopenicillin) - covers Streptococcus pneumoniae, Haemophilus influenzae, and other common pathogens 1, 2, 3
• Tetracycline - has advantage of covering Mycoplasma pneumoniae 1, 2

Alternative agents when first-line options cannot be used 1:

• Macrolides (azithromycin, clarithromycin, roxithromycin) - use only in regions with low pneumococcal macrolide resistance or for penicillin allergy 2
• Oral cephalosporins 1
• Third-generation quinolones (levofloxacin, moxifloxacin) - reserve for clinically relevant bacterial resistance to first-line agents 2

Special circumstances requiring alternative therapy 1:

• High frequency of beta-lactamase-producing H. influenzae in the area: use amoxicillin + beta-lactamase inhibitor 1
• Chronic lung disease or recent aminopenicillin failure: use amoxicillin + beta-lactamase inhibitor 1
• Young adults during Mycoplasma pneumoniae epidemic: consider macrolide or tetracycline 1

Critical principle: All empirical therapy must cover Streptococcus pneumoniae, which remains the most important pathogen for morbidity and mortality 2, 4

Treatment Duration and Monitoring

• Standard treatment duration: 5-7 days 1
• For Streptococcus pyogenes infections: minimum 10 days to prevent acute rheumatic fever 3
• Continue therapy minimum 48-72 hours beyond symptom resolution 3

Patient instructions for follow-up 1, 2:

• Return if fever does not resolve within 48 hours of starting antibiotics 1
• Expect cough may persist longer than antibiotic course 1
• Return if symptoms persist beyond 3 weeks 2
• Clinical improvement should occur within 3 days 2

Investigations

For outpatient management, investigations are generally NOT recommended 1:

• Microbiological sputum examination: not recommended for patients without risk factors 1
• Blood tests (WBC, CRP): not recommended for uncomplicated cases 1
• Chest radiograph: not routinely needed in outpatient setting 1

Consider investigations only when 1:

• Risk factors for unusual microorganisms present 1
• Failure of first-line empirical therapy 1
• Focal chest signs suggesting pneumonia 1

Management of COPD Exacerbations

Antibiotic indications for AECOPD 1:

• Majority of patients with exacerbations benefit from antibiotic treatment 1
• Obtain sputum culture before starting antibiotics, particularly if hospitalization required 1
• Stratify patients by risk of Pseudomonas infection 1
• Adjust empirical antibiotics based on culture results 1

Common Pitfalls to Avoid

Do NOT prescribe antibiotics for 1:

• Viral LRTIs without bacterial superinfection 1
• Upper respiratory tract infections to prevent LRTI (ineffective) 1
• Prophylaxis in chronic bronchitis or COPD (not recommended) 1

Avoid these errors:

• Ignoring local antibiotic resistance patterns when selecting therapy 2
• Failing to recognize severity markers requiring hospital referral 1
• Prescribing antibiotics for acute bronchitis in otherwise healthy patients 4
• Using fluoroquinolones as first-line therapy (reserve for resistance situations) 2

Prevention Strategies

Strongly recommended 1:

• Annual influenza vaccination for high-risk patients (age ≥65, chronic cardiac/pulmonary disease, diabetes, institutionalized) 1
• Pneumococcal vaccination for at-risk adults 1

NOT recommended for LRTI prevention 1:

• Prophylactic antibiotics 1
• Oral bacterial extracts 1
• Regular inhaled steroids or long-acting β2-agonists specifically for LRTI prevention 1
• Oral mucolytics 1
• Homeopathic substances 1