Immunology Review Corner

Prepared by Thao N. Tran, M.D., Stony Brook University Hospital- SUNY; Karla Lowe, M.D., Walter Reed Medical Center; and John Norvell, M.D., Vanderbilt University.

Chapter 44: Development, Structure, and Physiology in Normal and Asthmatic Lung

1. In fetal lung development, airway branching and development are completed by 16 weeks of gestation. During which week of gestation does the development of the alveoli begin?
a. 18
b. 24
c. 28
d. 36

2. Which of the following statements regarding structural changes in the asthmatic lung is correct?
a. Only moderate to severe asthmatics have structural alterations in their airways.
b. Using high-resolution computed tomography, airway wall thickening has been found to the greatest extent in the large airways.
c. Airway wall thickening has been correlated with the degree of airway hyperresponsiveness, as assessed by methacholine challenge.
d. Airway wall thickening has only been observed in cases of fatal asthma.

3. Which of the following statements regarding airway remodeling in the asthmatic lung is true?
a. Epithelial hyperplasia is limited to the central airway.
b. Subepithelial fibrosis has been observed only in severe asthmatics and is not reversible with corticosteroid therapy.
c. Smooth muscle atrophy is a common finding in the asthmatic airway.
d. Fatal cases of asthma of short duration, unlike the nonfatal cases, have significantly increased number of mucous glands.

4. Which of the following statements is correct?
a. The forced expiratory volume at one second (FEV1) tends to be decreased to a greater degree than the peak expiratory flow (PEF) in patients with asthma.
b. PEF is significantly decreased, whereas FEV1 remains normal, in cases of upper airway obstruction.
c. Forced expiratory flow at 25% to 75% of forced vital capacity (FEF25-75) is more reproducible than FEV1.
d. PEF is a reflection of airflow in the distal airways.

5. Which of the following statements about the FEV1/FVC ratio is true?
a. The ratio reflects the airflow resistance in the larger central airways, not the distal airways.
b. A ratio less than 0.8 is a sensitive indicator of airflow limitation.
c. A ratio greater than 0.8 rules out airflow limitation.
d. A falsely low FEV1/FVC can be observed in cases of mild asthma with air trapping (secondary to the increased FVC).

6. Which of the following plethysmography findings is most consistent with the diagnosis of mild asthma?
a. Total lung capacity (TLC) is decreased.
b. Residual volume (RV) is increased.
c. Functional reserve capacity (FRC) is decreased.
d. Expiratory reserve volume (ERV) is increased.

7. According to a study on inhaled budesonide, how many hours after the first dose of the inhaled corticosteroid is a reduction in bronchial reactivity noted?
a. 4 hours
b. 6 hours
c. 8 hours
d. 12 hours

8. A clinically significant bronchodilator response on pulmonary function testing is currently defined as:
a. A greater than 26% change in FEV1 or FVC
b. A greater than 20% change in FEV1/FVC
c. A greater than 12% change in FEV1 or FVC
d. A greater than 8% change in FEV1/FVC

9. A decrease in which of the following indices of lung volume is the major predictor of morbidity and mortality?
a. Forced vital capacity (FVC)
b. TLC
c. RV
d. FRC

10. Which of the following statements regarding the diffusing capacity of carbon monoxide (DLCO) is the most accurate?
a. DLCO correlates with gas exchange.
b. DLCO is decreased in asthmatic patients.
c. Measurement of DLCO can determine the alveolar volume (VA).
d. In normal subjects, the alveolar volume is less than the TLC.

Answers:
1. c, pg. 727
2. c, pg. 728
3. d, pg. 729
4. a, pg. 731
5. b, pg. 732
6. b, pg. 732
7. b, pg. 733
8. c, pg. 737
9. a, pg. 737
10. c, pg. 738