Bronchial asthma is a condition of the lungs which is
characterized by periodic, reversible constriction (narrowing) of the
bronchi. Why does constriction occur periodically? Constriction occurs because bronchi are
hyperreactive to a variety of stimuli to which the patient is exposed intermittently.
Why can't the patient breathe?
- Bronchi and bronchioles contain thick, tenacious mucous plugs. The mucous
contains Curschmann's spirals, eosinophils and Charcot-Leyden crystals.
- Other characteristic histologic findings which lead to narrowing of the bronchus
include: thickening of the basement membrane, submucosal edema, hypertrophy of the
submucosal glands and smooth muscle cells. (Refer to Figure 15-14 in your textbook).
- Extrinsic or atopic asthma: This group is an example of type I
IgE-mediated hypersensitivity reaction to foreign antigens. Begins in childhood. The child
(his or her respiratory tract mast cells) is sensitized to a substance which is extrinsic
to the body. A series of chemical and structural changes occur in the bronchi with
exposure to the foreign substance. Clinical examples: pollen, food, animal dander. (Refer
to Figure 15-13 in your textbook).
- Intrinsic or non-atopic: This group is an example of a
non-immune reaction causing asthma. Clinical examples: aspirin, virus, stress, exercise.
Acute attack of dyspnea, prolonged coughing producing a large quantity of mucous,