What is the appropriate management for a patient with reversible airway obstruction, reduced Forced Expiratory Volume in 1 second (FEV1) to Forced Vital Capacity (FVC) ratio, normal Forced Vital Capacity (FVC), and improved lung function with bronchodilator use?

Diagnosis: Reversible Airway Obstruction (Asthma)

This patient has asthma, not COPD, based on the significant bronchodilator reversibility demonstrated on spirometry. The key distinguishing feature is the improvement in FEV1 and FVC with bronchodilator administration, which defines reversible airway obstruction characteristic of asthma rather than the largely irreversible obstruction seen in COPD 1, 2.

Diagnostic Interpretation

The spirometric pattern clearly indicates asthma:

• Reduced FEV1/FVC ratio with normal FVC confirms airflow obstruction 1
• Significant improvement with bronchodilator (>12% and >200 mL increase in FEV1) meets diagnostic criteria for asthma 2
• Normal diffusing capacity (DLCO) argues strongly against COPD, as COPD typically shows reduced DLCO due to emphysematous changes 1

The British Thoracic Society guidelines explicitly state that COPD is characterized by airflow obstruction that is "not fully reversible and does not change markedly over several months," which directly contradicts this patient's presentation 1. In contrast, asthma is defined by reversible airway obstruction that responds to bronchodilators 2.

Management Algorithm

Initial Pharmacotherapy

Start with an inhaled short-acting beta-2 agonist (SABA) as rescue medication:

• Albuterol (salbutamol) via metered-dose inhaler for as-needed symptom relief 3, 4
• Onset of action within 5 minutes, with maximum effect at 1 hour and duration of 3-6 hours 4
• Proper inhaler technique is critical; consider spacer devices if hand-breath coordination is problematic 5

Step-Up Therapy Based on Symptom Control

If symptoms require SABA use more than twice weekly, add daily inhaled corticosteroid (ICS):

• ICS represents the most efficient anti-asthma therapy and should be the foundation of maintenance treatment 5
• Dosing should be individualized based on symptom control and lung function monitoring 5

For persistent symptoms despite ICS, add a long-acting beta-2 agonist (LABA):

• Long-acting bronchodilators like salmeterol provide sustained bronchodilation 3, 6
• Never use LABA monotherapy in asthma—always combine with ICS due to increased risk of asthma-related hospitalization and death with LABA alone 6

Alternative Bronchodilators

Consider adding anticholinergic agents if inadequate response:

• May have additive effects when combined with beta-2 agonists 5
• Individual therapeutic trial with peak-flow monitoring can demonstrate efficacy 5

Monitoring and Follow-Up

Schedule follow-up in 4-6 weeks to assess:

• Response to therapy and symptom control 3
• Inhaler technique verification 3
• Need for treatment adjustment 3

Perform annual spirometry to monitor disease progression 3

Critical Pitfalls to Avoid

Do not misdiagnose this as COPD based solely on reduced FEV1/FVC ratio:

• The significant bronchodilator reversibility (improvement in both FEV1 and FVC) definitively indicates asthma 2
• COPD diagnosis requires post-bronchodilator FEV1/FVC <0.7 that remains obstructed 1, 2
• Misdiagnosis could lead to undertreatment with inadequate anti-inflammatory therapy

Do not rely on single-dose reversibility testing to predict long-term bronchodilator response:

• While this patient shows clear reversibility supporting asthma diagnosis, the British Thoracic Society notes that single-dose tests don't predict symptomatic benefit from prolonged bronchodilator use in general 1
• Therapeutic trials with objective monitoring remain important 1

Ensure proper assessment technique:

• Post-bronchodilator spirometry should be performed to confirm diagnosis, as pre-bronchodilator measurements may overestimate obstruction 3
• Maximum sustained effort during testing is essential for accurate results 7