Does she have asthma or chronic obstructive pulmonary disease (COPD)?

Clarifying the Diagnosis: Does She Have Asthma or COPD?

If this patient does not have asthma or COPD, then you must establish what respiratory condition she does have through systematic evaluation with spirometry and clinical assessment, as both diseases require objective confirmation of airflow obstruction for diagnosis. 1

Diagnostic Confirmation Required

The absence of asthma or COPD must be confirmed objectively, not assumed based on symptoms alone:

• Spirometry is mandatory to definitively rule out both conditions, as medical history and physical examination alone are unreliable for excluding these diagnoses 1
• A post-bronchodilator FEV1/FVC ratio ≥0.70 would exclude COPD 1, 2
• Normal spirometry with no bronchodilator reversibility and no airway hyperresponsiveness would argue against asthma 1, 2

Key Distinguishing Features to Assess

If you're uncertain about the diagnosis, systematically evaluate these specific clinical characteristics:

Features Suggesting Asthma (if present):

• Age and onset: Symptoms beginning before age 40, particularly in childhood 3
• Variability: Symptoms that vary throughout the day, worse at night/early morning 3
• Reversibility: Significant bronchodilator response (FEV1 increase >12% and >200 mL, or >15% and >400 mL) 1
• Atopy: Personal or family history of allergy, rhinitis, eczema 3
• Triggers: Clear worsening with exercise, viral infections, allergens, weather changes 1

Features Suggesting COPD (if present):

• Age and smoking: Mid-life onset (typically >40 years) with significant smoking history (>10 pack-years) 1, 3
• Progressive course: Slowly progressive symptoms over years, not episodic 3
• Minimal reversibility: Post-bronchodilator FEV1/FVC <0.70 with minimal improvement 1, 2
• Chronic symptoms: Persistent dyspnea and productive cough, not intermittent 1

Alternative Diagnoses to Consider

If spirometry and clinical features exclude both asthma and COPD, systematically evaluate these alternative causes of respiratory symptoms:

Cardiac Causes:

• Heart failure: Fine basilar crackles, dilated heart on chest X-ray, peripheral edema, history of ischemic heart disease 3
• This is a frequent and dangerous mimic, particularly in older patients 3

Infectious/Structural Causes:

• Bronchiectasis: Large volume purulent sputum, coarse crackles, clubbing, frequent infections 3
• Tuberculosis: Lung infiltrate on imaging, microbiological confirmation, relevant risk factors 3

Other Obstructive Diseases:

• Obliterative bronchiolitis: Younger onset, often nonsmokers, history of rheumatoid arthritis or fume exposure 3

Critical Pitfalls to Avoid

• Do not rely on symptoms alone: Cough, sputum, wheeze, and even partial bronchodilator response are unhelpful in differentiating between chronic asthma and COPD 3
• Physical examination has poor sensitivity: It cannot reliably detect or exclude moderately severe COPD 3
• Age <40 with obstructive features: Warrants α1-antitrypsin deficiency testing and family screening 3

Management Approach When Diagnosis is Uncertain

If the diagnosis remains unclear after initial evaluation, specialist referral is mandatory to establish a definitive diagnosis 3:

• Symptoms disproportionate to lung function deficit require investigation for bronchiectasis 3
• Frequent infections dominate the clinical picture necessitate exclusion of bronchiectasis 3
• Consider high-resolution CT chest if spirometry and clinical features are discordant 3