Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss / EGPA) MCQ — NEET PG Practice Question | NEETPGAI
Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss / EGPA)
medium
stethoscope Medicine
A 47-year-old woman with a 7-year history of adult-onset steroid-dependent asthma and chronic rhinosinusitis with nasal polyps presents with mononeuritis multiplex (wrist drop), palpable purpura on the legs, and migratory pulmonary infiltrates. CBC shows eosinophilia of 28% (absolute count 7,200/microliter). Spirometry shows the pattern marked **A** in the diagram: FEV1 58% predicted with 18% improvement (+340 mL) after bronchodilator administration. p-ANCA/MPO-ANCA is positive at moderate titer. Which of the following best explains the spirometric finding marked **A** in the context of this patient's diagnosis?
A. The obstructive pattern with reversibility represents eosinophilic pneumonia with alveolar hemorrhage, which is the primary pulmonary manifestation of EGPA
B. The obstructive pattern with significant bronchodilator reversibility reflects severe asthma, which is a cardinal prodromal feature of EGPA that precedes vasculitic manifestations by years
C. The obstructive pattern reflects restrictive physiology masked by concurrent emphysema from smoking-related lung disease
D. The obstructive pattern indicates fixed airway obstruction from subglottic stenosis, requiring urgent laryngeal intervention
Explanation
Why option 1 is correct
The obstructive spirometric pattern marked A with significant bronchodilator reversibility (>12% and >200 mL) directly reflects the severe asthma that is a nearly universal feature in EGPA patients. According to the ACR/EULAR 2022 EGPA classification criteria and Harrison's 21e, asthma is a cardinal prodromal (phase 1) manifestation that typically precedes vasculitic features (phase 3) by years. In this patient, the 7-year history of adult-onset, steroid-dependent asthma followed by systemic vasculitis (mononeuritis multiplex, purpura) exemplifies the classic triphasic evolution of EGPA. The reversibility on bronchodilator testing confirms active, responsive airway obstruction typical of asthma rather than fixed obstruction.
Why each distractor is wrong
Option 2: Fixed upper airway obstruction from subglottic stenosis would produce a fixed obstructive pattern (marked C in the diagram) with minimal or no bronchodilator reversibility. The 18% improvement with bronchodilator rules out fixed obstruction and confirms asthma-type reversibility.
Option 3: While eosinophilic pneumonia and alveolar hemorrhage do occur in EGPA's eosinophilic phase (phase 2), they typically produce a restrictive pattern (marked B in the diagram) with elevated DLCO from hemorrhage, not an obstructive pattern with reversibility. The obstructive pattern here is from asthma, not from pulmonary eosinophilic infiltration.
Option 4: Emphysema would produce irreversible airway obstruction; the 18% improvement with bronchodilator is incompatible with emphysematous destruction. Smoking-related disease does not explain the acute systemic vasculitis, eosinophilia, and positive p-ANCA.
High-YieldNEET PG
EGPA evolves in three phases—prodromal asthma/allergies (years) → eosinophilic infiltration → vasculitis; obstructive spirometry with reversibility is the hallmark of the asthma phase that nearly all EGPA patients have.
