Confusable diagnoses · PANCE / PANRE

Chronic Obstructive Pulmonary Disease vs Asthma

Written & clinically reviewed by Ryan Busch, PA-C · Updated August 2026 · Report an error

Chronic Obstructive Pulmonary Disease and Asthma are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.

Chronic Obstructive Pulmonary Disease vs Asthma at a glance

  • Chronic Obstructive Pulmonary Disease: Progressive, largely irreversible airflow limitation from chronic bronchitis and/or emphysema.
  • Asthma: Chronic reversible airway inflammation with episodic bronchoconstriction.

Try two board-style questions on Chronic Obstructive Pulmonary Disease vs Asthma

Real questions from the FirstPassPA bank, with the full explanation. Pick an answer — no signup, no email.

Question 1PulmonaryMedium
A 55-year-old man with chronic obstructive pulmonary disease (COPD) is admitted with an acute exacerbation. SpO2 is 88% on room air. Which of the following is the most appropriate oxygen saturation target?
  • ASpO2 98-100%
  • BSpO2 94-98%
  • CSpO2 88-92%
  • DSpO2 84-87%
Reveal answer & full explanation
Correct answer: C — SpO2 88-92%
  • ASpO2 98-100%
  • BSpO2 94-98%
  • CSpO2 88-92%✓
  • DSpO2 84-87%

Why SpO2 88-92% is correct

  • In acute exacerbations of chronic obstructive pulmonary disease (COPD), the target SpO2 is 88-92%.
  • Higher saturations risk worsening hypercapnia via the Haldane effect and ventilation/perfusion (V/Q) mismatch.

Why the others are wrong

  • SpO2 98-100% — over-oxygenation in COPD risks CO2 retention and respiratory acidosis via the Haldane effect and V/Q mismatch
  • SpO2 94-98% — an appropriate target for most acutely ill patients without CO2-retention risk, but too high for a COPD patient prone to hypercapnia
  • SpO2 84-87% — unnecessarily low and risks tissue hypoxia; the goal is 88-92%, not deliberate hypoxemia

Additional high-yield points

  • Use controlled low-flow oxygen (Venturi mask preferred).
  • Initiate bilevel positive airway pressure (BiPAP) if pH falls below 7.35 after initial therapy.
Question 2PulmonaryEasy
A 22-year-old woman with asthma presents to the emergency department with severe dyspnea. She speaks in single words, uses accessory muscles, and has a respiratory rate of 32/min, heart rate of 124/min, and SpO₂ of 89% on room air. Peak expiratory flow is 35% of predicted. After three albuterol nebulizer treatments she has minimal improvement. Which of the following is the most appropriate next step in management?
  • AIV methylprednisolone and IV magnesium sulfate
  • BOral prednisone with continued nebulized albuterol
  • CInhaled ipratropium added to continuous albuterol
  • DEndotracheal intubation and mechanical ventilation
Reveal answer & full explanation
Correct answer: A — IV methylprednisolone and IV magnesium sulfate
  • AIV methylprednisolone and IV magnesium sulfate✓
  • BOral prednisone with continued nebulized albuterol
  • CInhaled ipratropium added to continuous albuterol
  • DEndotracheal intubation and mechanical ventilation

Why IV methylprednisolone and IV magnesium sulfate is correct

  • This is a severe asthma exacerbation with life-threatening features: peak expiratory flow <40% of predicted (35%), SpO₂ <90% on room air (89%), single-word speech, accessory muscle use, and minimal response to three albuterol nebulizer treatments
  • Per current GINA guidance, a severe exacerbation not responding to initial bronchodilator therapy warrants early systemic corticosteroids plus, as an adjunct, IV magnesium sulfate 2 g over 20 minutes (smooth muscle relaxation) — given alongside (not instead of) continued bronchodilators and ipratropium, with ICU-level disposition
  • The IV route is preferred over oral dosing when severe respiratory distress makes reliable oral intake uncertain and intubation remains a possibility

Why the others are wrong

  • Oral prednisone with continued nebulized albuterol — Oral steroids with continued nebulizers suit a moderate exacerbation but are insufficient escalation for refractory, hypoxemic disease that warrants IV magnesium (premature closure on a moderate-exacerbation plan)
  • Inhaled ipratropium added to continuous albuterol — Ipratropium is a reasonable adjunct in severe asthma, but this option omits the systemic corticosteroids and IV magnesium that drive recovery; no plan without steroids is best here (right-diagnosis-wrong-step)
  • Endotracheal intubation and mechanical ventilation — Intubation is reserved for impending respiratory failure (drowsiness, silent chest, rising CO₂, exhaustion), none of which is present; maximal medical therapy comes first (anchoring on the low SpO₂)
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Side-by-side comparison

FeatureChronic Obstructive Pulmonary DiseaseAsthma
At a glanceProgressive, largely irreversible airflow limitation from chronic bronchitis and/or emphysema.Chronic reversible airway inflammation with episodic bronchoconstriction.
Classic presentationHoover sign (paradoxical inward movement of lower ribs on inspiration), 'tripod' posture, prolonged expiration.; Chronic productive cough (chronic bronchitis: ≥3 months/year × 2 years); Progressive exertional dyspnea graded by the mMRC scale: 0 = only with strenuous exercise; 1 = when hurrying or walking up a slight hill; 2 = walks…Wheezing that improves with short-acting beta-agonist; nocturnal cough; symptom relief between episodes.; Episodic wheeze, cough (often nocturnal), chest tightness, dyspnea; Triggered by allergens, exercise, cold air, viral URIs, NSAIDs, beta-blockers, emotional stress; Diurnal variation: worse at night and early morning; Expiratory…
Workup / key labsGOLD 2026: symptoms + risk factor exposure + post-bronchodilator FEV1/FVC <0.7. Severity by FEV1 % predicted; clinical group for initial (treatment-naive) therapy by exacerbations in the past 12 months and symptoms: E = ≥1 moderate or severe exacerbation; A = no exacerbations with mMRC 0-1 and CAT <10; B = no exacerbations with mMRC ≥2…GINA: history of variable respiratory symptoms + confirmed variable expiratory airflow limitation (bronchodilator reversibility, methacholine positivity, or PEF variability).; CBC (eosinophilia supports allergic phenotype); Total IgE and allergen-specific IgE if considering biologics or ABPA; FeNO (fractional exhaled nitric oxide) —…
ImagingCXR — hyperinflation (flattened diaphragms, >10 posterior or >6 anterior ribs visible), increased AP diameter, bullae; CT chest — emphysema pattern (centrilobular, panlobular, paraseptal), exclude lung cancer; required for lung volume reduction or transplant evaluation; ECG — right axis deviation, P pulmonale, multifocal atrial…CXR — usually normal or hyperinflation; obtain to exclude alternative diagnoses or complications (pneumothorax, pneumonia); HRCT if bronchiectasis or alternative diagnosis suspected
First-line treatmentSmoking cessation — single most important intervention; reduces rate of FEV1 decline; Pulmonary rehabilitation for mMRC ≥2 or after exacerbation — the best-evidenced intervention for improving dyspnea, exercise capacity and quality of life; Vaccinations: annual influenza, pneumococcal (PCV20 or PCV21 alone, or PCV15 followed by PPSV23),…Since 2019, GINA no longer recommends SABA-only treatment; all adults and adolescents should receive ICS-containing therapy. The US NAEPP 2020 update differs: Step 1 = PRN SABA alone (intermittent asthma), Step 2 = daily low-dose ICS + PRN SABA, Steps 3-4 (age 5 and older) = ICS-formoterol daily and PRN (SMART); Step 1-2 (mild):…

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Full outlines

Chronic Obstructive Pulmonary Disease (COPD) Asthma All 514 diagnoses

Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.