<unk> s can occur for a number of reasons. Lower respiratory tract conditions such as asthma, chronic obstructive pulmonary disease (COPD), and emphysema can result in contraction of the airways. Other causes are side effects of topical decongestants such as oxymetazoline and phenylephrine. Both of these medications activate alpha-1 adrenergic receptors that result in smooth muscle constriction. Non-selective beta blockers are known to facilitate<unk>  as well. Beta blockers bind into the β2 receptors and block the action of epinephrine and norepinephrine from binding to its receptors, causing shortness of breath. Additionally, the pediatric population is more susceptible to disease and complications from<unk>  due to their airway diameter being smaller; applying Poiseuille's Law to the airways it is clear that airflow resistance through a tube is inversely related to the radius of the tube to the fourth power, therefore, decreases in airway results in significant flow impediments.
Bronchospasm
Cyclospasm
Laryngospasm
Apnea
Cornea
Hyperpnea
Cough
Tachypnea