Managing Common Respiratory Infections

Differentiating Viral vs Bacterial

80-90% of adult URIs are viral. Key discriminators:

• Modified Centor Criteria (3+ points = 40% strep probability): Tonsillar exudate, tender nodes, fever, no cough
• Procalcitonin: <0.25 ng/mL suggests viral etiology (94% NPV for bacterial pneumonia)
• CRP: >40 mg/L increases bacterial likelihood (LR+ 3.1)

Symptom Management

• Cough: 2.5mL honey reduces frequency better than dextromethorphan (NNT=6)
• Nasal: Saline irrigation decreases sinusitis duration by 2.1 days (95% CI 1.2-3.0)
• Fever: Allow <102°F unless patient discomfort - reduces viral load by 1 log/day

Red Flag Indicators

Symptom	Concern
Fever >3 days	Secondary bacterial infection
Pleuritic chest pain	Pneumonia/PE

Prevention Strategies

• Vaccination: Flu vaccine reduces hospitalization by 40% in high-risk groups
• PPE: Surgical masks decrease URI transmission by 67% (95% CI 54-77%)
• Environmental: HEPA filters reduce aerosolized virus load by 82%

Antibiotic Stewardship

• Delayed Rx: 65% fill rate when given "wait-and-see" prescriptions
• Narrow-spectrum: Amoxicillin remains 1st-line for uncomplicated bacterial URIs
• Duration: 5-day courses equally effective for most URIs (exception: sinusitis)