Source:

Nielsen
EW
,
Hull
JH
,
Backer
V
.
High prevalence of exercise-induced laryngeal obstruction in athletes
.
Med Sci Sports Exerc.
2013
;
45
(
11
):
2030
2035
; doi:
https://doi.org/10.1249/MSS.0b013e318298b19a

To understand the prevalence and characteristics of exercise-induced laryngeal obstruction (EILO), a group of diagnoses that includes exercise-induced laryngomalacia and vocal cord dysfunction, investigators from Denmark and the United Kingdom reviewed the medical records of all athletes referred to the asthma service at a Danish academic hospital over a 2-year period. Athletes were defined as those who exercised >10 hours per week. Each participant received a clinical assessment of respiratory symptoms, had anthropometric data collected (age, gender, and BMI), had atopic status measured by skin prick or radioallergosorbent test, and received a baseline pulmonary function test and bronchodilator reversibility (BDR) testing. If the BDR test was negative, 1 or more bronchoprovocation tests (BPT) were performed to confirm or rule out asthma. Lastly, each participant underwent continuous laryngoscopy during exercise (CLE) testing. This is the gold standard test for diagnosis of EILO and uses flexible nasendoscopy to provide continuous video recording of the larynx throughout exercise. The investigators compared clinical characteristics and bronchial hyperreactivity between athletes with and without EILO.

There were 91 athletes referred during the study period, 3 of whom were excluded due to incomplete data. Of the remaining 88 participants, the median age was 17 years; 43% were male. At the time of referral, 53 athletes (60%) were taking regular asthma medications. Based on study BDR and/or BPT data, only 38 of the 88 participants (43%) had evidence of asthma. Using CLE, 31 participants (35.2%) had evidence of EILO, with female participants having increased odds of the diagnosis compared to males (OR=4.1; 95% CI, 1.52–11.04). Of those diagnosed with EILO, 12 (39%) also had evidence of asthma. There weres no differences in BMI, atopic status, or the frequency of positive BPT between EILO and non-EILO groups. In addition, report of inspiratory wheeze or dyspnea did not discriminate between participants with or without EILO.

The investigators conclude that EILO is a prevalent and important differential diagnosis in athletes presenting with exercise-induced respiratory symptoms.

Dr LaBella has disclosed no financial relationship relevant to this commentary. The commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.

Exercise-induced bronchospasm (EIB) is often considered the most common cause of exercise-induced respiratory symptoms in athletes, and it is frequently diagnosed and treated based solely on reported symptoms. However, a significant percentage of athletes diagnosed with EIB in this way will have normal pulmonary function and a negative BPT, suggesting that athletes with respiratory symptoms are often misdiagnosed. This study alerts clinicians to the relatively high prevalence of EILO as a cause of respiratory symptoms in athletes, and the type of testing necessary to distinguish it from EIB. EILO should also be considered in athletes with a laboratory-confirmed diagnosis of EIB but who continue to have persistent symptoms despite treatment with...

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