Bronchospasm

Bronchospasm is a sudden contraction of smooth muscle in the bronchial walls that narrows the airways and can cause wheezing, coughing, or shortness of breath.

Bronchial smooth muscle: Smooth muscle in the walls of the bronchi and bronchioles that regulates airway caliber. Its contraction directly narrows the airways during bronchospasm.
Asthma: A chronic airway disease marked by variable respiratory symptoms and variable expiratory airflow limitation. Asthma commonly causes recurrent bronchospasm through airway inflammation and hyperresponsiveness.
Wheezing: A high-pitched musical sound produced by airflow through narrowed airways, usually during exhalation. Wheezing can signal bronchospasm, though its absence does not rule it out.
Laryngospasm: Involuntary closure of the vocal cords that temporarily obstructs airflow at the larynx. It obstructs airflow at the upper airway rather than through bronchial smooth-muscle contraction.
Airway hyperresponsiveness: An exaggerated airway-narrowing response to stimuli that cause little reaction in healthy airways. It makes bronchial smooth muscle more likely to contract in response to triggers.
Anaphylaxis: A rapid, systemic allergic reaction that can cause airway swelling, breathing difficulty, and circulatory collapse. Bronchospasm can be one component of its acute respiratory effects.
Spirometry: A lung-function test that measures how much and how quickly a person can exhale. Testing before and after a bronchodilator can reveal reversible airflow obstruction.
Stridor: A harsh, usually inspiratory sound caused by turbulent airflow through a narrowed upper airway. It often points to upper-airway obstruction, unlike the typical expiratory wheeze of bronchospasm.
Bronchoconstriction: Narrowing of the lower airways caused by contraction of bronchial smooth muscle. It names the muscle-driven narrowing at the center of bronchospasm.
Exercise-induced bronchoconstriction: Transient airway narrowing triggered by exercise, occurring with or without chronic asthma. It is a recognizable, trigger-specific form of bronchospasm.

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