Inducible laryngeal obstruction: an official joint European Respiratory Society and European Laryngological Society statement

Abstract

Inducible laryngeal obstruction (ILO) describes an inappropriate, transient, reversible narrowing of the larynx in response to external triggers. ILO is an important cause of a variety of respiratory symptoms and can mimic asthma. Current understanding of ILO has been hampered by imprecise nomenclature and variable approaches to assessment and management. A task force of the European Respiratory Society (ERS) and European Laryngological Society (ELS) was thus set up to address this, and to identify research priorities.A literature search identified relevant articles published until June 2016, using all identifiable terms for ILO, although including only articles using laryngoscopy. In total, 172 out of 252 articles met the inclusion criteria, summarised in sections on diagnostic approach, aetiology, comorbidities, epidemiology and treatment. The consensus taxonomy published by ERS, ELS and the American College of Chest Physicians (ACCP) in 2015 is used throughout this statement.We highlight the high prevalence of ILO and the clinical impact for those affected. Despite recent advances, most aspects of this condition unfortunately remain incompletely understood, precluding firm guidance. Specifically, validated diagnostic and treatment algorithms are yet to be established, and no randomised control studies were identified in this search; hence we also make recommendations for future research.

Diagnosis of concomitant inducible laryngeal obstruction and asthma

“…2 Two patients in our series demonstrated supraglottic closure, which has been usually described in association with exercise provocation. 2 Two patients in our series demonstrated supraglottic closure, which has been usually described in association with exercise provocation.…”

“…1,2 Traditionally, the gold standard for diagnosis has been the demonstration on direct laryngoscopy of abnormal (hence paradoxical) adduction of the vocal folds during the respiratory cycle accompanying a symptomatic episode. It is an umbrella term for any triggered laryngeal obstruction occurring at either the supraglottic (arytenoid region, epiglottis or false vocal folds) and/or glottic (true vocal folds) level of the larynx and includes the condition also known as paradoxical vocal fold motion disorder (PVFM), or vocal cord dysfunction (VCD).…”

“…,2 We also examined for laryngoscopic evidence of exacerbating conditions such as laryngopharyngeal reflux, chronic rhinosinusitis and oral candidiasis. Video stroboscopy was performed when clinically relevant and available.…”

Nordic consensus statement on the systematic assessment and management of possible severe asthma in adults

“…Continuous laryngoscopic exercise testing (CLE) may be performed to visualize the larynx during exercise. CLE testing has demonstrated that a large proportion of patients with symptoms suggestive of VCD may demonstrate supraglottic closure of the aryepiglottic folds [76]. The term Inducible Laryngeal Obstruction (ILO) has been proposed, to cover both glottic and supraglottic obstruction, induced by stimuli such as exercise (EILO) or external stimulants [76].…”

Continuous laryngoscopy during provocation in the assessment of inducible laryngeal obstruction

“…This phenomenon, most commonly termed vocal cord dysfunction and more recently termed inducible laryngeal obstruction (ILO), is often misdiagnosed and mistreated as asthma . This may be explained by the lack of a robust, accepted diagnostic methodology …”