bronchospasm

Bronchospasm refers to the sudden constriction of bronchial smooth muscle, leading to narrowing of the airways and reduced airflow. It is a component of several respiratory conditions and can occur independently. The pathophysiology involves airway smooth muscle contraction, mucosal edema, and increased mucus production, often driven by inflammatory mediators in allergic or irritant-induced responses. Triggers include allergens, cold air, exercise, respiratory infections, smoke, pollutants, and certain medications.

Symptoms include wheezing, coughing, chest tightness, and shortness of breath, with signs of increased work of breathing in more severe cases. Diagnosis is clinical, supported by spirometry showing reversible airflow limitation; peak expiratory flow may be reduced and improves with bronchodilators. In acute settings, lung auscultation may reveal diffuse wheezes; arterial oxygen saturation is monitored.

Management depends on severity and underlying cause. Acute bronchospasm is treated with inhaled short-acting beta-agonists (e.g., albuterol) and, if needed, anticholinergic agents. Systemic corticosteroids are used for persistent symptoms or frequent episodes. Oxygen therapy is given for hypoxemia. In severe cases, hospitalization, continuous bronchodilator therapy, or mechanical ventilation may be required. Treat underlying triggers and avoid precipitants; in anaphylaxis or severe allergic reactions, epinephrine is indicated.

Prognosis varies with cause and prompt treatment. With appropriate management, most episodes resolve, but recurrent bronchospasm is common in asthma and COPD. Prevention focuses on trigger avoidance and adherence to controller medications, proper inhaler technique, and asthma action plans.