Key Points
- Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
- Use system-specific risk tools to guide testing and disposition.
- Order high-yield tests first; escalate imaging when indicated.
- Start evidence-based initial therapy and reassess frequently.
Algorithm
- Primary survey and vitals; IV access and monitors.
- Focused history/physical; identify red flags and likely etiologies.
- Order system-appropriate labs and imaging (see Investigations).
- Initiate guideline-based empiric therapy (see Pharmacology).
- Reassess response; arrange consultation and definitive management.
Clinical Synopsis & Reasoning
Asthma exacerbations reflect acute airway inflammation and bronchoconstriction triggered by infection, allergens, or irritants. Assess severity via work of breathing, PEF/FEV₁, and gas exchange; identify risk factors for near‑fatal events (prior intubation, repeated ED visits). Distinguish from COPD, anaphylaxis, or PE when atypical features are present.
Treatment Strategy & Disposition
Administer repeated SABA (± SAMA) nebulizations, systemic corticosteroids early, and controlled oxygen to achieve target saturations. Consider IV magnesium for severe attacks and non‑invasive ventilation in impending fatigue; intubate if refractory with attention to dynamic hyperinflation. Discharge when PEF ≥70% predicted and stable, ensuring inhaled corticosteroid‑containing regimen and action plan; admit for persistent hypoxemia, rising CO₂, or poor response.
Epidemiology / Risk Factors
- Smoking/chronic lung disease; infections or immobility (VTE)
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| CXR | Infection/edema/PTX | Consolidation/effusion/PTX | |
| ABG/VBG | Oxygenation/ventilation | Hypoxemia/hypercapnia | |
| CT chest (indicated) | PE/other | Findings vary |
Response by Peak Flow
| PEF (% predicted) | Disposition |
|---|---|
| ≥70% and improving | Discharge with meds plan |
| 40–69% | Observe/continue therapy; consider admit |
| <40% or drowsy/CO₂ rising | ICU/acute care; consider NIV/intubation |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Albuterol (neb) | β2-agonist | Minutes | Bronchodilation rescue | Tachycardia tremor |
| Ipratropium (neb) | M3 antagonism | Minutes | Adjunct bronchodilation (moderate-severe) | Dry mouth |
| Magnesium sulfate (IV) | Ca²⁺ antagonism (bronchodilation) | Minutes | Severe exacerbation refractory | Hypotension |
| Systemic corticosteroid | Glucocorticoid receptor | Hours | Reduce airway inflammation | Hyperglycemia, mood changes |
| Epinephrine (IM) | α/β agonist | Minutes | Impending respiratory failure/anaphylaxis overlap | Arrhythmia |
Prognosis / Complications
- Depends on severity/oxygenation; respiratory failure risk
Patient Education / Counseling
- Explain red flags and when to seek emergent care.
- Reinforce medication adherence and follow-up plan.
Notes
Avoid routine antibiotics. Check for triggers (viral illness, allergens). Educate on inhaler technique and action plan.