Inducible Laryngeal Obstruction/Vocal Cord Dysfunction and the Role It Plays in Refractory Asthma

Abstract

Chronic asthma accounts for a significant amount of unscheduled office and emergency department (ED) visits. According to the latest World Health Organization statistics, asthma worldwide affects 300 million individuals and creates a substantial health burden by restricting the patient’s lifetime activities. Data estimate that asthma causes a loss of disability-adjusted life years over 150,000/year [1]. While most individuals with asthma can be controlled with current therapies, 5-10% of patients have difficult-to-control/refractory asthma. Severe or refractory asthma places a significant burden on the patient and often requires treatment with systemic glucocorticoids, which have significant side effects. The American Thoracic Society and the European Respiratory Society define refractory asthma as asthma that requires treatment with high-dose inhaled corticosteroids (ICS) plus a second controller and/or systemic corticosteroids to prevent it from becoming ‘‘uncontrolled’’ or asthma that remains ‘‘uncontrolled’’ despite this aggressive therapy. To fully meet this definition the diagnosis of asthma needs to be confirmed and comorbidities addressed as well. The above are considered major criteria for severe asthma and only one needs to be present for considering the diagnosis of refractory asthma [2]. For these reasons, clinicians must learn to identify and formulate additional diagnoses of “asthma imitators” [3]. One of the more common disorders associated with difficult-to-control asthma is vocal cord dysfunction (VCD) [4]. This disorder is known by many names, but current nomenclature endorsed by European and American societies correctly refers it as “Inducible Laryngeal Obstruction” (ILO) [5]. The following case demonstrates the importance of recognizing the clinical and spirometric features of ILO when asthma remains “refractory” to multiple therapies