What is the role of systemic corticosteroids (e.g. prednisone) in managing influenza-induced bronchial asthma exacerbation?

Role of Systemic Corticosteroids in Influenza-Induced Bronchial Asthma Exacerbation

Systemic corticosteroids are essential in managing influenza-induced bronchial asthma exacerbations and should be administered early in the treatment course to reduce morbidity, mortality, and prevent relapse. 1, 2

Indications and Benefits

• Systemic corticosteroids are a cornerstone therapy for treating the inflammatory component of asthma exacerbations, including those triggered by influenza 1, 2
• They significantly reduce hospital admission rates and risk of relapse when administered early in the treatment course 2
• Underuse of corticosteroids is associated with increased mortality in asthma exacerbations 1, 3
• Corticosteroids work by suppressing the inflammatory cascade, reversing mucosal edema, decreasing vascular permeability, and inhibiting the release of inflammatory mediators 4

Recommended Dosing Regimen

• For moderate to severe exacerbations, administer oral prednisone 40-60 mg daily until peak expiratory flow (PEF) reaches 70% of predicted or personal best 1, 3
• For outpatient management, prescribe a "burst" of 40-60 mg in single or divided doses for a total of 5-10 days 1, 3
• For patients who are seriously ill or vomiting, use IV hydrocortisone 200 mg every 6 hours 1
• No known advantage exists for IV administration over oral therapy when gastrointestinal absorption is not compromised 3

Timing of Administration

• Administer systemic corticosteroids early in the treatment course, as their anti-inflammatory effects may take 6-12 hours to appear 1, 3
• Delaying corticosteroid administration can lead to poorer outcomes and potentially fatal consequences 1, 3

Severity Assessment and Treatment Algorithm

1. Assess exacerbation severity:

   • Mild: Dyspnea only with activity, PEF ≥70% predicted/personal best 5
   • Moderate: Dyspnea interferes with usual activity, PEF 40-69% predicted/personal best 5
   • Severe: Dyspnea at rest, interferes with conversation, PEF <40% predicted/personal best 5
   • Life-threatening: Too dyspneic to speak, perspiring, PEF <25% predicted/personal best 5

2. Treatment approach based on severity:

   • Mild: May be managed at home with inhaled SABA; consider short course of oral systemic corticosteroids 5
   • Moderate: Usually requires office/ED visit; administer oral systemic corticosteroids and frequent inhaled SABA 5
   • Severe/Life-threatening: Requires ED visit/hospitalization; administer systemic corticosteroids immediately along with frequent inhaled SABA 5

Monitoring and Follow-up

• Measure PEF 15-30 minutes after starting treatment and then according to response 1
• Continue oxygen therapy to maintain SaO₂ >90% (>95% in pregnant women and patients with heart disease) 1
• Monitor for clinical improvement, including reduced work of breathing, decreased respiratory rate, and improved PEF 5, 1

Common Pitfalls to Avoid

• Underestimating the severity of asthma exacerbations, which can lead to inadequate treatment 1, 3
• Delaying corticosteroid administration, which worsens outcomes 1, 3
• Using sedatives, which are contraindicated in asthma exacerbations 1
• Prescribing antibiotics unless there is clear evidence of bacterial infection 1
• Relying on home remedies like drinking large volumes of liquids, breathing warm moist air, or using over-the-counter antihistamines, which have no proven efficacy and may delay proper care 5