A 32-year-old man presents with a 3-month history of progressive dyspnea on exertion. He denies chest pain, fever, or recent infections. Vital signs are normal. Chest examination reveals end-expiratory wheezing bilaterally. Spirometry shows FEV1 of 78% predicted with an FEV1/FVC ratio of 0.68. To evaluate for asthma, the patient undergoes methacholine bronchoprovocation testing. Which of the following results would be most consistent with asthma?
- A)FEV1 decreases by 8% at the maximum methacholine concentration of 16 mg/mL
- B)FEV1 decreases by 22% at a methacholine concentration of 4 mg/mLGABARITO
- C)FEV1 increases by 15% following inhaled albuterol
- D)Diffusion capacity (DLCO) is 125% of predicted with normal FEV1
- E)Peak flow variability of 12% between morning and evening measurements over 2 weeks
Explicação
A ≥20% drop in FEV1 at any methacholine concentration during bronchoprovocation testing is diagnostic of asthma (airway hyperresponsiveness). This patient demonstrates a 22% decrease at 4 mg/mL, confirming bronchial hyperreactivity characteristic of asthma. Me... Ver explicação completa e trilha adaptativa →