Question
An 8-year-old boy is brought to the emergency department because of shortness of breath and dry cough for 2 days. His symptoms began after he helped his father clean the basement. He is allergic to shellfish. Respirations are 26/min. Physical examination shows diffuse end-expiratory wheezing and decreased inspiratory-to-expiratory ratio. This patient’s symptoms are most likely being caused by inflammation of which of the following structures?
| A. |
Alveoli
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| B. |
Pleural cavity
|
| C. |
Respiratory bronchioles
|
| D. |
Terminal bronchioles
|
Show Answer
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Correct Answer � D
Explanation
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|
Answer D) Terminal bronchioles
Explanation:
In a patient with a history of atopy, wheezing and prolonged expiratory phase after exposure to allergens (mold spores) are most likely signs of asthma.
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The symptoms of asthma are primarily caused by inflammation of the terminal bronchioles.
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Terminal bronchioles are lined with smooth muscle but lack the cartilage found in larger airways.
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When an allergen triggers a hypersensitivity reaction there is bronchial submucosal edema and smooth muscle contraction and the airways collapse, as they don’t have the support of cartilage. This collapse leads to the symptoms of asthma.
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