Obstructive

Asthma: Diagnosis, Classification & Management

Added by Dr. Andrew · Last updated 2024-01-15

Overview

Asthma is a heterogeneous disease characterized by chronic airway inflammation, variable airflow obstruction, and bronchial hyperresponsiveness. GINA 2024 guidelines emphasize phenotyping and personalized treatment, particularly with biologics for severe asthma.

Key Points

1Diagnosis: variable airflow obstruction (reversibility ≥12% and ≥200 ml post-BD, or positive bronchoprovocation)
2GINA steps: Step 1 (SABA PRN) → Step 5 (add-on biologics/bronchial thermoplasty)
3ICS is the cornerstone of maintenance therapy — reduces exacerbations and mortality
4Severe asthma: consider eosinophilic (IL-5/IL-4/IL-13 pathway) vs T2-low phenotype
5Biologics: mepolizumab, benralizumab (anti-IL-5), dupilumab (anti-IL-4/13), omalizumab (anti-IgE)
6Status asthmaticus: IV Mg sulfate, heliox, ketamine, possible intubation

Clinical Pearls

FeNO >25 ppb suggests eosinophilic airway inflammation — predicts ICS response
Aspirin-exacerbated respiratory disease (AERD): triad of asthma + nasal polyps + NSAID sensitivity
Vocal cord dysfunction (VCD) mimics asthma — inspiratory stridor, normal spirometry between episodes
Churg-Strauss (EGPA): asthma + eosinophilia + vasculitis — check ANCA

Board High-Yield

Exam Focus

GINA: ICS-formoterol as both maintenance AND reliever (SMART therapy) — superior to SABA alone
Mepolizumab/benralizumab: for severe eosinophilic asthma (eos ≥150–300)
Dupilumab: for severe eosinophilic or OCS-dependent asthma
Omalizumab: for allergic asthma with elevated IgE
Intubation in status asthmaticus: use low RR (8–10), long expiratory time, tolerate high PaCO₂

ABIM Exam Weight

17.5%

Obstructive Lung Disease represents approximately 17.5% of the PCCM certification exam.