What are the diagnostic criteria and treatment options for asthma?

Asthma Diagnosis and Management

Asthma diagnosis requires a compatible clinical history of episodic respiratory symptoms and objective confirmation of variable expiratory airflow limitation through pulmonary function testing, with spirometry and bronchodilator reversibility testing being the gold standard. 1

Diagnostic Criteria for Asthma

Key Clinical Symptoms

• Recurrent episodes of:

  • Wheezing
  • Cough (particularly at night)
  • Difficulty breathing
  • Chest tightness

• Symptoms typically worsen with:

  • Exercise
  • Viral infections
  • Allergen exposure
  • Irritants
  • Weather changes
  • Strong emotions/stress
  • Nighttime (nocturnal asthma)

Objective Testing

1. Spirometry with bronchodilator reversibility (Gold Standard):

   • Demonstrates airflow obstruction (FEV1/FVC < 0.7)
   • Shows bronchodilator reversibility (≥12% and ≥200 mL improvement in FEV1 after bronchodilator)
   • Must be performed when patient is symptomatic for highest sensitivity

2. Peak Expiratory Flow (PEF) Monitoring:

   • Alternative when spirometry unavailable or normal despite clinical suspicion
   • Diurnal variation >20% over 1-2 weeks suggests asthma
   • Useful for home monitoring and assessing variability

3. Bronchial Challenge Testing:

   • Reserved for cases where other testing is inconclusive
   • Measures airway hyperresponsiveness
   • Positive test supports diagnosis but has low specificity

4. Fractional Exhaled Nitric Oxide (FeNO):

   • Values ≥45-50 ppb suggest eosinophilic inflammation
   • Particularly useful in atopic asthma
   • Supportive but not diagnostic on its own

5. Response to Treatment:

   • Improvement in lung function after 4 weeks of inhaled corticosteroid treatment
   • Can be used as a diagnostic tool when other tests are inconclusive

Treatment Options

Step-wise Approach to Management

Step 1: Intermittent Asthma

• Short-acting beta-agonists (SABAs) like albuterol as needed
• 2-4 puffs (200-400 μg) every 4-6 hours as needed

Step 2: Mild Persistent Asthma

• Low-dose inhaled corticosteroids (ICS) daily
• SABA as needed for rescue

Step 3: Moderate Persistent Asthma

• Options (based on domain of concern):
  • Low-dose ICS + long-acting beta-agonist (LABA)
  • Medium-dose ICS
  • Low-dose ICS + leukotriene receptor antagonist (LTRA)

Step 4: Moderate-to-Severe Persistent Asthma

• Medium-dose ICS + LABA
• Consider adding LTRA or tiotropium

Step 5: Severe Persistent Asthma

• High-dose ICS + LABA
• Consider adding tiotropium or biologic therapy (e.g., omalizumab, mepolizumab)

Step 6: Very Severe Persistent Asthma

• High-dose ICS + LABA + oral corticosteroids
• Consider biologic therapy

Special Considerations

• Children (4-11 years): Treatment options for step-up therapy are limited; selection depends on impairment, risk, and clinician-patient preference 2

• Adolescents: Involve them in developing written asthma action plans and reviewing adherence 2

• Older Adults: Consider comorbidities, potential drug interactions, and increased sensitivity to medication side effects 2

Monitoring and Follow-up

• Regular assessment of symptom control and lung function
• Spirometry recommended at least every 1-2 years
• Follow-up visits at 1-6 month intervals after control is achieved
• Written action plans for all patients
• Monitor for potential adverse effects of medications:
  • Oral candidiasis with ICS (advise rinsing mouth after use)
  • Increased risk of pneumonia in COPD patients using ICS
  • Potential adrenal suppression with high-dose ICS
  • Decreased bone mineral density with long-term ICS use
  • Glaucoma and cataracts with long-term ICS use

Common Pitfalls in Diagnosis

1. Relying solely on clinical history without objective testing:

   • Leads to misdiagnosis and inappropriate treatment
   • Always confirm with spirometry or other objective measures

2. Testing during asymptomatic periods:

   • May yield false negatives
   • Consider repeated testing during symptomatic periods

3. Using "reactive airway disease" as a placeholder diagnosis:

   • Delays proper treatment
   • Complete diagnostic workup is essential

4. Failing to consider differential diagnoses:

   • Vocal cord dysfunction
   • COPD
   • Asthma-COPD overlap
   • Upper airway cough syndrome
   • Gastroesophageal reflux

5. Inappropriate antibiotic use:

   • Antibiotics not indicated for routine asthma management
   • Avoid azithromycin as first-line treatment for suspected reactive airway disease

By following these diagnostic criteria and treatment approaches, clinicians can effectively diagnose asthma and provide appropriate management to improve patient outcomes, reduce exacerbations, and enhance quality of life.