Spirometry — Asthma in Pregnancy MCQ — NEET PG Practice Question | NEETPGAI
Spirometry — Asthma in Pregnancy
medium
stethoscope Medicine
A 28-year-old primigravida at 24 weeks gestation presents with worsening wheezing, nocturnal cough, and chest tightness 3–4 times per week requiring her rescue inhaler nightly. She has a history of childhood asthma and atopic dermatitis. On examination, bilateral expiratory wheezes and prolonged expiratory phase are noted. Pre-bronchodilator spirometry shows FEV₁ 68% predicted, FVC 88% predicted, and FEV₁/FVC ratio 0.62. After 4 puffs of inhaled albuterol via spacer, FEV₁ rises to 84% predicted—an increase of 380 mL and 23.5% from baseline. The flow-volume loop shows a scooped expiratory limb that improves toward normal after bronchodilator.
The spirometric pattern marked **A** in the diagram is most consistent with which of the following diagnoses?
A. Asthma with significant bronchodilator reversibility
B. Restrictive lung disease secondary to pregnancy
C. Vocal cord dysfunction with normal airway reactivity
D. Chronic obstructive pulmonary disease with fixed airflow obstruction
Explanation
Why "Asthma with significant bronchodilator reversibility" is right
The pattern marked A demonstrates obstructive airflow (FEV₁/FVC 0.62) with an FEV₁ increase of 23.5% AND 380 mL after bronchodilator—exceeding the diagnostic threshold of ≥12% AND ≥200 mL improvement. This bronchodilator reversibility is the hallmark of asthma and distinguishes it from fixed obstruction. The scooped expiratory limb on flow-volume loop, elevated FeNO (58 ppb), and clinical history of atopy further support asthma. According to GINA 2024 and NAEPP guidelines, this spirometric pattern with reversibility confirms asthma diagnosis in pregnancy, where 4–8% of pregnant patients are affected. The rule of thirds applies: one-third improve, one-third remain unchanged, and one-third worsen during gestation—this patient is in the worsening group, necessitating stepwise pharmacotherapy with inhaled corticosteroids (budesonide preferred in pregnancy) and short-acting beta-agonists.
Why each distractor is wrong
Chronic obstructive pulmonary disease with fixed airflow obstruction: COPD presents with fixed obstruction (pattern B) showing minimal or no bronchodilator response (<12% or <200 mL improvement). This patient's 23.5% and 380 mL improvement rules out COPD. COPD is also rare in young women without significant smoking history.
Restrictive lung disease secondary to pregnancy: Restrictive patterns (pattern C) show reduced FVC with normal or elevated FEV₁/FVC ratio (>0.80). This patient has a low FEV₁/FVC ratio (0.62), confirming obstruction, not restriction. Pregnancy may reduce functional residual capacity but does not cause airflow obstruction.
Vocal cord dysfunction with normal airway reactivity: Vocal cord dysfunction typically presents with a flattened inspiratory limb on flow-volume loop and normal spirometry at rest. This patient has clear obstructive spirometry with bronchodilator responsiveness, inconsistent with VCD. FeNO elevation also supports eosinophilic airway inflammation rather than mechanical VCD.
High-YieldNEET PG
Bronchodilator reversibility (≥12% AND ≥200 mL FEV₁ improvement) is the diagnostic hallmark of asthma; untreated asthma in pregnancy poses greater fetal risk than ICS/SABA therapy—budesonide is the preferred ICS (FDA category B).
Williams Obstetrics 26e Ch 51; GINA 2024 Report; NAEPP Asthma in Pregnancy Update
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
