Keywords: Exercise, wheezing, bronchospasm (PubMed Search)
You are covering a sporting event or working an ED shift when a young adolescent athlete without significant PMH presents with SOB and wheezing associated with exercise.
You immediately think exercise-induced asthma, prescribe a short-acting bronchodilator and pat yourself on the back.
While you may be right, there is increasing recognition of an alternative diagnosis
Exercise-induced laryngeal obstruction (EILO)
During high intensity exercise, the larynx can partially close, thereby causing a reduction in normal airflow. This results in the reported symptoms of SOB and wheezing.
This diagnosis has previously been called exercise induced vocal cord dysfunction. As the narrowing most frequently occurs ABOVE the level of the vocal cord, EILO is a more correct term.
While exercise induced bronchoconstriction has a prevalence of 5-20%, EILO is less common with a prevalence of 5-6%.
Patients are typically adolescents, with exercise associated wheezing and SOB, frequently during competitive or very strenuous events. Wheezing is inspiratory and high-pitched. Symptoms are unlikely to be present at time of medical contact unless you are at the event as resolution occurs within 5 minutes though associated cough or throat discomfort can persist after exercise cessation. EIB symptoms typically last up to 30 minutes following exercise.
Inhaler therapy is unlikely to help though some athletes report subjective partial relief. This may be explained as approximately 10% of individuals have both EIB and EILO.
In athletes with respiratory symptoms referred to asthma clinic, EILO was found in 35%.
Consider EILO in athletes with unexplained respiratory symptoms especially in those with ongoing symptoms despite appropriate therapy for EIB.