Pulmonary · PANCE / PANRE

Asthma

Chronic reversible airway inflammation with episodic bronchoconstriction.

Also known as: asthma, reactive airway disease, bronchial asthma, RAD, wheezing

Overview

Heterogeneous chronic inflammatory airway disease characterized by reversible airflow obstruction, bronchial hyperresponsiveness, and variable respiratory symptoms (wheezing, dyspnea, chest tightness, cough).

Epidemiology

~8% of US adults, ~7% of children. Higher prevalence in non-Hispanic Black and Puerto Rican populations. Most childhood-onset cases are atopic (Th2-high); adult-onset is more often non-atopic.

🔒 Free preview limit reached

Keep reading — start your free trial

You've read your 2 free diagnosis previews. Create your free account to unlock the full Asthma outline — plus all 514 diagnoses, 3,500+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.

Start your 7-day free trial → Sign in

Free to start · No credit card · Cancel anytime

Risk factors

Atopy (eczema, allergic rhinitis, food allergy) — the 'atopic march'
Family history of asthma or atopic disease
Environmental allergens: dust mites, cockroach, mold, pet dander, pollen
Tobacco smoke exposure (prenatal and postnatal)
Respiratory viral infections in infancy (especially RSV, rhinovirus)
Obesity, GERD
Occupational exposures (isocyanates, flour, animal proteins)

Pathophysiology

Th2-driven inflammation with eosinophils, mast cells, IgE, and cytokines (IL-4, IL-5, IL-13) → airway smooth muscle constriction, mucosal edema, mucus hypersecretion, and over time, airway remodeling (subepithelial fibrosis, smooth muscle hypertrophy). Triggers (allergens, exercise, cold air, viruses, NSAIDs in aspirin-exacerbated respiratory disease) provoke acute bronchoconstriction.

Clinical presentation

Symptoms

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

Signs / physical exam

Expiratory wheeze on auscultation, prolonged expiratory phase
Use of accessory muscles, tachypnea, tachycardia in acute exacerbation
Pulsus paradoxus >10 mmHg in severe exacerbation
Silent chest (no wheeze) = ominous sign of severe airflow obstruction

Classic findings

Wheezing that improves with short-acting beta-agonist; nocturnal cough; symptom relief between episodes.

Differential diagnosis

COPD — Older smoker, persistent (not reversible) airflow obstruction on PFTs, FEV1/FVC <0.7 post-bronchodilator that does not normalize
Vocal cord dysfunction — Inspiratory stridor (not expiratory wheeze), throat tightness, normal PFTs between episodes, flattened inspiratory flow-volume loop; diagnosed by laryngoscopy during episode
Heart failure ('cardiac asthma') — Orthopnea, PND, elevated BNP, cardiomegaly and pulmonary edema on CXR, S3 gallop
Bronchiectasis — Chronic productive cough with copious purulent sputum, recurrent infections, tram-track opacities on HRCT
Foreign body aspiration — Sudden onset in toddler or after choking event, unilateral wheeze, focal hyperinflation on expiratory CXR
Pulmonary embolism — Acute dyspnea, pleuritic pain, hypoxia, tachycardia; risk factors for VTE
ABPA (allergic bronchopulmonary aspergillosis) — Poorly controlled asthma + central bronchiectasis + elevated total IgE (>1000) and Aspergillus-specific IgE
Eosinophilic granulomatosis with polyangiitis (EGPA) — Asthma + peripheral eosinophilia + sinusitis + neuropathy or pulmonary infiltrates

Diagnostic workup

Diagnostic criteria

GINA: history of variable respiratory symptoms + confirmed variable expiratory airflow limitation (bronchodilator reversibility, methacholine positivity, or PEF variability).

Labs

CBC (eosinophilia supports allergic phenotype)
Total IgE and allergen-specific IgE if considering biologics or ABPA
FeNO (fractional exhaled nitric oxide) — elevated in Th2-high asthma

Imaging

CXR — usually normal or hyperinflation; obtain to exclude alternative diagnoses or complications (pneumothorax, pneumonia)
HRCT if bronchiectasis or alternative diagnosis suspected

Other studies

Spirometry with bronchodilator response — first-line: obstructive pattern (FEV1/FVC reduced) with ≥12% AND ≥200 mL improvement in FEV1 post-bronchodilator confirms reversibility
Methacholine challenge if spirometry normal but high clinical suspicion — PC20 ≤8 mg/mL is positive
Peak expiratory flow monitoring for home tracking; diurnal variability >10% supports diagnosis

Diagnostic algorithm

GINA Step	Preferred Controller	Reliever
1	As-needed low-dose ICS-formoterol	Low-dose ICS-formoterol PRN
2	Daily low-dose ICS OR PRN ICS-formoterol	Low-dose ICS-formoterol PRN
3	Low-dose ICS-LABA (formoterol)	Low-dose ICS-formoterol PRN (MART)
4	Medium-dose ICS-LABA	Low-dose ICS-formoterol PRN (MART)
5	High-dose ICS-LABA + add-on (LAMA, biologic)	Low-dose ICS-formoterol PRN; refer specialist

GINA 2024 stepwise treatment for adults and adolescents (Track 1, ICS-formoterol-based).

Treatment

First-line

GINA 2024 has eliminated SABA-only treatment; all adults and adolescents should receive ICS-containing therapy
Step 1-2 (mild): low-dose ICS-formoterol PRN (preferred 'MART' approach) — budesonide-formoterol or beclomethasone-formoterol
Step 3 (moderate): low-dose ICS-LABA daily + ICS-formoterol PRN as reliever
Step 4: medium-dose ICS-LABA + ICS-formoterol PRN
Step 5: high-dose ICS-LABA, refer for biologic/specialist
Inhaled corticosteroid (ICS) options: fluticasone, budesonide, mometasone, beclomethasone, ciclesonide
Long-acting beta-agonist (LABA): formoterol, salmeterol, vilanterol (NEVER as monotherapy in asthma)

Second-line / adjunct

Long-acting muscarinic antagonist (LAMA) add-on: tiotropium, umeclidinium
Leukotriene receptor antagonist: montelukast (FDA black-box warning for neuropsychiatric effects), zafirlukast
Biologics for severe uncontrolled asthma: omalizumab (anti-IgE), mepolizumab/reslizumab/benralizumab (anti-IL-5/IL-5R), dupilumab (anti-IL-4Rα), tezepelumab (anti-TSLP)
Oral corticosteroid burst for exacerbation: prednisone 40-60 mg daily × 5-7 days (no taper needed for short courses)
Acute exacerbation: nebulized albuterol + ipratropium, systemic corticosteroids, oxygen to SpO2 ≥92% (≥94% in pregnancy), magnesium sulfate 2 g IV for severe

Complications

Status asthmaticus, respiratory failure requiring intubation
Pneumothorax, pneumomediastinum from barotrauma
Airway remodeling with fixed obstruction (asthma-COPD overlap)
ICS side effects: oral candidiasis, dysphonia, decreased growth velocity in children (small, reversible)
Aspirin-exacerbated respiratory disease (AERD/Samter triad): asthma + nasal polyps + NSAID sensitivity

PANCE pearls

GINA 2024 emphasizes anti-inflammatory reliever (ICS-formoterol) over SABA-only — SABA monotherapy is no longer recommended at any step.
Silent chest, exhaustion, drowsiness, paradoxical thoracoabdominal motion, or pCO2 normalization (after initial hyperventilation) signal impending respiratory failure.
Exercise-induced bronchoconstriction: pretreat with SABA 15 min before exercise; if frequent, daily ICS.
Pregnancy: budesonide is the preferred ICS (most safety data). Uncontrolled asthma is more dangerous than medication.
Beta-blockers and NSAIDs can trigger severe exacerbations in susceptible patients — verify tolerance before use.

References

GINA 2024 — Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2024 Update (ginasthma.org)
NAEPP 2020 — 2020 Focused Updates to the Asthma Management Guidelines (Cloutier et al., J Allergy Clin Immunol 2020)
SYGMA Trials — As-Needed Budesonide-Formoterol vs Maintenance Budesonide in Mild Asthma (O'Byrne et al., NEJM 2018)
ATS/ERS — ATS/ERS Standards for Diagnosis of Asthma in Adults and Children (Louis et al., Eur Respir J 2022)

Practice Pulmonary questions on FirstPassPA

Turn this outline into retention. 3,500+ board-style questions with an AI tutor that explains every answer — free to start, no card required.

Start studying free → Browse 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. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants.