Editing Bronchospasm (section)

==Cause==
Bronchospasms 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 bronchospasm as well. Beta blockers bind to the β2 receptors and block the action of epinephrine and norepinephrine causing shortness of breath.<ref>{{cite journal |last1=Ahmed |first1=Rubab |last2=Branley |first2=Howard M. |title=Reversible bronchospasm with the cardio-selective beta-blocker celiprolol in a non-asthmatic subject |journal=Respiratory Medicine CME |date=1 January 2009 |volume=2 |issue=3 |pages=141–143 |doi=10.1016/j.rmedc.2008.10.019 |url=https://www.sciencedirect.com/science/article/pii/S1755001708001036 |issn=1755-0017|url-access=subscription }}</ref>

Additionally, the pediatric population is more susceptible to disease and complications from bronchospasm 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.<ref> {{cite web | last1 = Edwards | first1 = Lauren | last2 = Borger | first2 = Judith | title = Pediatric Bronchospasm | url = https://www.ncbi.nlm.nih.gov/books/NBK546685/ | publisher = statPearls | date = June 26, 2020 | pmid = 31536291 | access-date = November 22, 2020}}</ref>