bronchospazm

Bronchospasm is a sudden constriction of the smooth muscle surrounding the bronchi, causing narrowing of the airways. This leads to symptoms such as wheezing, coughing, shortness of breath, and chest tightness, and the effect is typically reversible with appropriate treatment.

Causes include chronic inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease, as well as acute reactions to allergens, viral infections, exercise, cold air, smoke, or certain medications. Exercise-induced bronchospasm occurs in many individuals during or after vigorous activity, and severe allergic or anaphylactic reactions can include bronchospasm as part of a systemic airway compromise.

Pathophysiology involves contraction of bronchial smooth muscle, airway wall edema, and increased mucus production, driven by airway inflammation and hyperresponsiveness. This increases airway resistance and reduces expiratory airflow, often reflected on spirometry as a decreased FEV1 and a reduced FEV1/FVC ratio, which may improve after bronchodilator use.

Diagnosis is clinical and supported by objective testing. Spirometry before and after inhaled bronchodilators helps confirm reversible obstruction. Peak expiratory flow monitoring can detect variability. In uncertain cases, bronchoprovocation tests using agents such as methacholine or an exercise challenge may be employed.

Treatment aims to relieve acute bronchospasm and control the underlying condition. Short-acting beta-agonists (for example, inhaled albuterol) provide rapid relief. Anti-inflammatory controller therapies, such as inhaled corticosteroids, reduce frequency and severity of episodes. In emergency settings, oxygen therapy and, when indicated, systemic corticosteroids, anticholinergic agents, or magnesium sulfate may be used. Avoidance of triggers and proper inhaler technique are important components of management.

Prognosis depends on the underlying disease and access to treatment; bronchospasm is usually reversible with prompt therapy, but recurrent events can affect quality of life.