Asthma Diagnosis and Treatment Protocol
Diagnosis
Establish the diagnosis of asthma by documenting recurrent episodes of airflow obstruction through spirometry in all patients ≥5 years old, demonstrating reversibility with ≥12% and ≥200 mL improvement in FEV₁ after bronchodilator administration. 1, 2, 3
Clinical History Requirements
- Document frequency of daytime symptoms (wheezing, breathlessness, chest tightness, cough) and nighttime awakenings 1, 2
- Quantify short-acting β-agonist (SABA) use per week 1
- Assess activity limitations and school/work absences 1
- Identify specific triggers: allergens (dust mites, pets, cockroaches), irritants (tobacco smoke), exercise, viral infections, weather changes, medications (aspirin, NSAIDs, beta-blockers) 4, 1, 2
- Evaluate for symptom variability over time and in response to triggers 2
Objective Testing
- Spirometry is mandatory at initial assessment for all patients ≥5 years old—medical history and physical examination alone are unreliable for diagnosis 4, 1
- Measure FEV₁ and FEV₁/FVC ratio; in children, FEV₁/FVC is more sensitive than FEV₁ alone 2
- Demonstrate reversibility: administer inhaled SABA and repeat spirometry showing ≥12% and ≥200 mL improvement in FEV₁ 1, 2, 3
- If spirometry is normal but asthma suspected, perform bronchoprovocation testing with methacholine, histamine, or exercise challenge—a negative test helps rule out asthma 4, 1
- Peak flow meters are designed for monitoring, not diagnosis, due to wide variability in devices and reference values 4
Critical Differential Diagnoses to Exclude
Adults:
- COPD (chronic bronchitis/emphysema)—obtain diffusing capacity; low DLCO increases COPD probability and makes asthma less likely 4, 5
- Congestive heart failure 4
- Pulmonary embolism 4, 1
- ACE inhibitor-induced cough 4, 1
- Vocal cord dysfunction—look for inspiratory flow-volume loop flattening on spirometry 4, 1
Children:
- Foreign body aspiration 4, 1
- Cystic fibrosis 1
- Vascular rings or laryngeal webs 4
- Laryngotracheomalacia, tracheal stenosis 4
All ages:
Additional Testing When Indicated
- Chest x-ray to exclude alternative diagnoses 4
- Allergy testing (skin or specific IgE) for perennial indoor allergens in patients with persistent asthma requiring daily medications 4, 1, 3
- Exhaled nitric oxide—high levels make allergic asthma more likely 5
Severity Classification (Treatment-Naïve Patients)
Classify severity before initiating therapy using both impairment and risk domains to determine the appropriate initial treatment step. 4, 1, 2
Severity Categories
Intermittent:
- Symptoms ≤2 days/week 1
- Nighttime awakenings ≤2×/month 1
- SABA use ≤2 days/week 1
- No interference with activities 1
- FEV₁ >80% predicted 1
Mild Persistent:
Moderate Persistent:
Severe Persistent:
- Symptoms throughout the day 1
- Nighttime awakenings often 7×/week 1
- Extreme activity limitation 1
- FEV₁ <60% predicted 1
Risk Assessment:
- ≥2 exacerbations requiring oral corticosteroids in past year indicates higher risk regardless of impairment level 1
Initial Treatment Protocol
Initiate treatment with inhaled corticosteroids (ICS) as first-line long-term controller therapy combined with SABA for symptom relief, using a stepwise approach based on severity classification. 1, 2, 3
Stepwise Pharmacotherapy by Severity
Step 1 (Intermittent):
- SABA as needed only 1
Step 2 (Mild Persistent):
- Low-dose ICS (preferred) 1, 3
- Alternative options: cromolyn, leukotriene modifier (montelukast), nedocromil, or sustained-release theophylline 4
Step 3 (Moderate Persistent):
Step 4:
- Medium-dose ICS + LABA 1
Step 5 (Severe Persistent):
Step 6:
Critical Treatment Principles
- Never use LABA as monotherapy—LABAs increase risk of serious asthma-related events when used alone 6
- SABA use >2 days/week (excluding exercise prophylaxis) indicates inadequate control requiring step-up 1, 3
- For exercise-induced bronchoconstriction, take SABA at least 2 hours before exercise; if already on daily SABA for chronic asthma, do not take additional dose 7
- Doubling ICS doses during exacerbations is not effective—use oral corticosteroids instead 4, 2
Ongoing Monitoring and Control Assessment
Schedule follow-up visits every 2-6 weeks when initiating therapy or stepping up, every 1-6 months once control achieved, and every 3 months when considering step-down. 4, 1, 2
At Every Visit Assess:
- Asthma control using validated measures (impairment and risk domains) 4, 1, 2
- Medication adherence 4, 1
- Inhaler technique—verify and correct at every visit 1, 2, 3
- Written asthma action plan understanding 4, 1
- Environmental trigger exposures 4, 1
- Comorbidities: rhinitis, sinusitis, GERD, obstructive sleep apnea, obesity 4, 1, 3
Objective Monitoring
- Perform spirometry at least every 1-2 years, more frequently if poorly controlled 4, 1
- Consider daily peak flow monitoring for patients with moderate-severe persistent asthma, history of severe exacerbations, or poor symptom perception 4, 1, 2
Control Categories (≥12 Years Old)
Well-Controlled:
- Symptoms ≤2 days/week 2
- Nighttime awakenings ≤2×/month 2
- SABA use ≤2 days/week 2
- No interference with activities 2
Not Well-Controlled or Very Poorly Controlled:
Adjusting Therapy
Before stepping up, verify medication adherence, correct inhaler technique, ensure environmental trigger control, and treat comorbidities (rhinitis, sinusitis, GERD, OSA, obesity). 1, 3
Step-Up Criteria
Step-Down Criteria
- Consider after ≥3 months of well-controlled asthma 1, 3
- Monitor closely at 3-month intervals during step-down 1
Patient Education and Self-Management
Develop a written asthma action plan with every patient, including instructions for daily management and managing worsening symptoms. 4, 1, 2, 3
Essential Education Components
- Distinguish long-term control medications (taken daily) from quick-relief medications (used as needed) 4, 1, 3
- Teach proper inhaler technique with spacer devices and verify at every visit 4, 1, 3
- Train self-monitoring using either symptoms or peak flow—benefits are similar 1, 2
- Recognize early signs of worsening: increased symptoms, nighttime awakenings, increased SABA use, declining peak flow 4
- Know when to increase SABA, when to add oral corticosteroids, and when to seek emergency care 4, 1
Environmental Control
- All patients must avoid tobacco smoke exposure 1
- For sensitized patients with persistent asthma, implement multifaceted allergen avoidance strategies (single interventions generally ineffective) 4, 1
- Reduce exposure to identified triggers: house dust mites, cockroaches, cat/dog allergens, irritants 4
- Consider allergen immunotherapy when clear relationship exists between symptoms and specific allergen exposure 1
Comorbidity Management
- Treat allergic rhinitis, sinusitis, GERD when present 4, 1
- Annual influenza vaccination for all patients with persistent asthma 4
Specialist Referral Indications
Refer for consultation or co-management when: 1
- Difficulty achieving or maintaining control 1
- ≥2 oral corticosteroid bursts in past year 1
- Any hospitalization for asthma 1
- Step 4 or higher care required 1
- Immunotherapy or omalizumab being considered 1
- Additional diagnostic testing needed (bronchoprovocation, vocal cord visualization) 1
- Life-threatening exacerbation history 4
Exacerbation Management
Home Management
- Increase SABA: up to 3 treatments at 20-minute intervals 4, 1
- Add short course of oral corticosteroids for moderate-severe exacerbations or inadequate response to SABA 4
- Remove or withdraw from environmental triggers 4
- Monitor response and communicate promptly with clinician about deterioration 4