bronchospasm
Meaning of bronchospasm: The reversible half of an asthma attack: muscle squeezing airways shut, distinct from the swelling and mucus that clear far more slowly.
Definition of bronchospasm
Bronchospasm is sudden tightening of the muscle wrapped around the small airways of the lungs, narrowing them so air cannot move freely. Wheeze, cough, chest tightness and difficulty breathing out follow. It comes on over minutes to hours and can ease just as quickly, either on its own or with an inhaled drug that relaxes that muscle.
How bronchospasm is built
- bronch/o Combining form · Greek bronchus, airway
- -spasm Suffix · Greek sudden involuntary contraction
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
What happens in the airway?
The small airways deep in the lung are wrapped in a thin sleeve of smooth muscle that normally adjusts their width quietly. In bronchospasm that muscle contracts hard and stays contracted, squeezing the tube it surrounds. A small drop in the width of a tube causes a large drop in the flow through it, so even modest narrowing makes breathing markedly harder. Air enters more easily than it leaves, and the lungs stay partly inflated, so each breath starts from an already full chest. The whistle of a wheeze is air forced through those narrowed channels. Muscle tightening is only part of an attack: the lining of the bronchiole also swells and pours out thick mucus, and both of those clear far more slowly than the spasm itself.
What sets it off?
Some airways are permanently oversensitive, a state called bronchial hyperresponsiveness, and in them ordinary stimuli provoke a reaction that most airways ignore. The same response can appear in lungs that were previously normal, given a strong enough trigger.
| Trigger | How it acts |
|---|---|
| Allergen such as pollen, dander or a food | Immune cells release histamine and related mediators onto the muscle |
| Viral chest infection | Leaves the airway lining inflamed and twitchy for weeks |
| Cold air or hard exercise | Cools and dries the airway surface |
| Smoke, fumes and strong odors | Stimulate irritant nerves in the airway wall |
| Certain medicines | Beta blockers remove a relaxing signal, and aspirin-type painkillers shift inflammatory chemistry |
When is it dangerous?
Severity is judged by how much air is moving, not by how much noise the chest makes. A wheeze that fades while the person is getting worse means too little air is passing to generate the sound, so a quiet chest in someone struggling to breathe is a grave finding rather than a reassuring one. Exhaustion, an inability to finish a sentence and drowsiness carry the same weight. Bronchospasm starting within minutes of a sting, a food or a drug, alongside hives, swelling of the lips or a fall in blood pressure, is part of anaphylaxis, a time-critical emergency rather than an asthma attack. Recurrent bronchospasm in an older adult with a long smoking history more often reflects COPD than allergy.
Also known as
Used in a sentence
Bronchospasm developed during induction of anesthesia and settled with an inhaled bronchodilator.
Good to know
A wheeze that fades as breathing worsens reflects too little air moving to make the sound rather than improvement, and bronchospasm accompanied by hives, swelling or falling blood pressure within minutes of an exposure describes anaphylaxis rather than asthma alone.
Word origin
Where “bronchospasm” comes from
Broncho- comes from the Greek bronchos, the windpipe, and spasm from the Greek spasmos, meaning a sudden involuntary pull.