How do you differentiate and manage Upper Respiratory Tract Infections (URTI) versus Lower Respiratory Tract Infections (LRTI)?

Differentiation and Management of Upper vs Lower Respiratory Tract Infections

The key to differentiating between Upper Respiratory Tract Infections (URTI) and Lower Respiratory Tract Infections (LRTI) lies in identifying the anatomical location of symptoms, with URTIs affecting structures above the larynx and LRTIs affecting the trachea, bronchi, bronchioles and lung parenchyma, requiring different management approaches based on severity and suspected etiology.

Anatomical and Clinical Differentiation

Upper Respiratory Tract Infections (URTIs)

• Affect structures above the larynx (nose, sinuses, pharynx, larynx)
• Typically present with rhinitis, nasal congestion, sore throat, and post-nasal drip 1
• Usually viral in etiology and self-limiting 2

Lower Respiratory Tract Infections (LRTIs)

• Affect structures below the larynx (trachea, bronchi, bronchioles, lung parenchyma) 3, 1
• Present with cough as the main symptom, plus at least one other lower respiratory tract symptom (sputum production, dyspnea, wheeze or chest discomfort/pain) 3
• Can be further classified into:
  • Acute bronchitis: Cough with or without sputum production in patients without chronic lung disease 3
  • Community-acquired pneumonia (CAP): Acute illness with cough and at least one of: new focal chest signs, fever >4 days, or dyspnea/tachypnea 3
  • Acute exacerbation of COPD (AECOPD): Worsening of baseline dyspnea, cough and/or sputum beyond day-to-day variability 3
  • Acute exacerbation of bronchiectasis: Worsening of baseline symptoms in patients with bronchiectasis 3

Diagnostic Approach

Key Differentiating Features

• Suspect pneumonia when a patient has acute cough plus one of: new focal chest signs, dyspnea, tachypnea, or fever lasting >4 days 3
• Chest radiograph should be performed to confirm pneumonia diagnosis when suspected 3
• Differentiating between tracheitis and acute bronchitis based on symptoms alone is often impossible in clinical practice 1

Special Considerations

• In elderly patients (>65 years), consider cardiac failure with orthopnea, displaced apex beat, and/or history of myocardial infarction 3
• Consider pulmonary embolism in patients with history of DVT/PE, immobilization in past 4 weeks, or malignant disease 3
• Consider chronic airway disease in patients with at least two of: wheezing, prolonged expiration, history of smoking, and symptoms of allergy 3, 4

Management Approach

URTIs

• Generally self-limiting and require only symptomatic treatment 2
• Antibiotics are rarely indicated 2, 5

LRTIs

• Antibiotic treatment should be considered in the following situations:
  • Suspected or confirmed pneumonia 3
  • Selected exacerbations of COPD (increased dyspnea, increased sputum volume, and increased sputum purulence) 3
  • Age >75 years with fever 3
  • Patients with cardiac failure, insulin-dependent diabetes mellitus, or serious neurological disorders 3

Antibiotic Selection for LRTIs When Indicated

• First-choice antibiotics: Tetracycline and amoxicillin 3, 6
• For patients with hypersensitivity: Newer macrolides (azithromycin, roxithromycin, clarithromycin) in areas with low pneumococcal macrolide resistance 3
• Consider local resistance patterns when selecting antibiotics 3, 7
• For bacterial resistance to first-line agents, consider levofloxacin or moxifloxacin 3

Symptomatic Treatment

• For dry, bothersome cough: Dextromethorphan or codeine can be prescribed 3
• Expectorants, mucolytics, antihistamines, and bronchodilators should NOT be prescribed for acute LRTI in primary care 3

Monitoring and Follow-up

• Advise patients to return if symptoms persist for >3 weeks 3
• Clinical effects of antibiotic treatment should be expected within 3 days; patients should contact their doctor if improvement is not seen 3
• Seriously ill patients (with high fever, tachypnea, dyspnea, relevant comorbidity, or age >65 years) should be seen again 2 days after the initial visit 3
• Patients should contact their doctor if fever exceeds 4 days or if dyspnea worsens 3

Common Pitfalls to Avoid

• Overuse of antibiotics for viral infections, which contributes to antibiotic resistance 2, 5
• Misdiagnosing tracheitis as asthma when wheezing is present 1
• Failing to consider alternative diagnoses like cardiac failure or pulmonary embolism in patients with respiratory symptoms 3
• Relying solely on clinical features to differentiate between viral and bacterial infections, as this has poor predictive value 8
• Delaying antibiotic treatment in cases of suspected pneumonia, which may increase mortality risk 5