Exercise-induced laryngeal obstruction

INTRODUCTION — Exercise-induced laryngeal obstruction (EILO) is the term used to describe breathing problems caused by inducible laryngeal obstruction isolated to exercise. EILO includes the entity described as "exercise-induced laryngomalacia" and replaces previously used terms including "vocal cord dysfunction" and "paradoxical vocal fold motion" in the context of exercise [1]. It is increasingly recognized as an important cause of exertional dyspnea [2].

The clinical presentation, evaluation, diagnosis, and treatment of EILO will be reviewed here. The evaluation and diagnosis of dyspnea, wheezing, asthma, and exercise-induced bronchoconstriction are discussed separately. (See "Approach to the patient with dyspnea" and "Asthma in children younger than 12 years: Initial evaluation and diagnosis" and "Asthma in adolescents and adults: Evaluation and diagnosis" and "Evaluation of wheezing in infants and children" and "Evaluation of wheezing illnesses other than asthma in adults" and "Exercise-induced bronchoconstriction".)

DEFINITION

Exercise-induced laryngeal obstruction (EILO) refers to narrowing of the laryngeal airway at the glottic (vocal folds) or supraglottic (above the glottis) level that occurs during exercise [3]. Other terms that have been used to describe EILO include exercise-induced vocal cord dysfunction (EI-VCD), exercise-induced laryngomalacia (EIL), and exercise-induced paradoxical vocal fold motion (EIPVFM). The broader term, laryngeal obstruction, is preferred because a substantial portion of EILO is attributable to narrowing of the supraglottic airway, rather than just the vocal folds.

Inducible laryngeal obstruction (ILO) describes inappropriate upper airway obstruction which may include adduction of the true vocal folds during inspiration in any setting including exercise. It is an umbrella term that includes EILO and was historically known as paradoxical vocal fold motion (PVFM). ILO/PVFM is discussed separately. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)".)

EPIDEMIOLOGY — EILO is a common condition among adolescents and young adult athletes, with prevalence estimates in the 5 to 8 percent range [4-7]. Prevalence across the age spectrum has not been clearly defined. EILO is generally more common among females than males [4-6]; in one study the female to male odds ratio of having EILO was 3.41 (95% CI 1.66-6.97) [4]. Elite athletes may have a higher prevalence than the general population, especially when considering involvement of the supraglottis [8].

PATHOPHYSIOLOGY — EILO is characterized by either glottic or supraglottic obstruction which is not present at rest [1]. Normally, exercise is associated with abduction of the vocal folds and aryepiglottic folds, which expands the laryngeal aperture during inhalation. The precise mechanism of EILO is not well-characterized, and a number of factors may contribute.

●Anatomic factors – Anatomic factors, such as airway size or pliability, may contribute to the frequency and severity of disease [9,10]. The benefit of supraglottoplasty in some patients suggests a potential structural contribution. (See 'Supraglottoplasty for refractory disease' below.)

●Neurologic factors – Neurologic factors have been hypothesized to play a role in diseases characterized by upper airway sensitivity [11]. Potential neurologic factors include dysfunction at an epithelial, neurologic, or muscular level. As an example of altered neurologic function, in a series of 54 patients with EILO, 75 had decreased laryngeal mechanosensitivity [12]. There appears to be an increase in respiratory neural drive in EILO patients which precedes visualized upper airway obstruction [13].

●Behavioral factors – Behavioral observations have be made in association with characteristic descriptions of EILO and inducible laryngeal obstruction (ILO)/paradoxical vocal fold motion (PVFM) [14]. However, assessments of adolescent behavioral features of EILO patients refute a consistent group effect [15]. When present, it is unclear if behavioral characteristics, such as obsessive-compulsive disorder (OCD) and other anxiety-spectrum disorders, are causally linked with disease, are unrelated associations, or if these have led to ascertainment bias in studies of disease populations. Possibly, panic reactions to EILO are a response to the choking feeling of laryngeal obstruction, rather than a contributor [16]. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)", section on 'Psychosocial disorders and stress'.)

●Other factors – Asthma, gastroesophageal or laryngopharyngeal reflux (GER or LPR), and rhinosinusitis may play a role as disease contributors, although the mechanisms remain hypothetical [17]. Importantly, triggers of bronchoconstriction (eg, methacholine or mannitol), other than exercise, are not necessarily the triggers for EILO [18]. Among 54 adolescents and young adults with EILO, 48 percent had typical symptoms of GER and 34 percent had extraesophageal symptoms of GER [12]. Examination of the laryngeal mucosa demonstrated erythema consistent with reflux in 75 percent.

CLINICAL PRESENTATION

Presentation — The prototypical patient with EILO is often described as a female adolescent competitive athlete that describes the repetitive onset of inspiratory stridor and breathlessness during high intensity exercise, followed by resolution within minutes after cessation of exercise [16]. However, the spectrum of disease presentations is much more varied across age, sex, and athletic level, and excessive focus on identifying prototypical patients may mislead clinicians. It is common to have delays in diagnosis related to clinical uncertainty [19,20].

Presentation prior to adolescence is also reported, especially in relationship to prominent supraglottic obstruction [10]. While the majority of published cases favor a female predominance, a large proportion of patients is male. (See 'Epidemiology' above.)

The athletic intensity associated with EILO is broadly variable, which may reflect the minute ventilation required by well-trained versus less well-trained athletes, or possibly a contribution from concomitant asthma [20,21].

Symptoms — The specific symptoms associated with EILO differ, although patients with EILO virtually always report dyspnea on exertion [12,19,22,23]. Other symptoms include stridor (80 percent), globus pharyngeus/sensation of a lump in the throat (54 percent), nonproductive cough (44 percent), difficulty swallowing saliva (27 percent), and hoarseness (22 percent) [12]. Chest tightness and throat tightness are sometimes reported [22].

While inspiratory stridor has been described back to the seminal publication [2], its presence or absence may simply be a function of disease severity and absolute airflow rather than a requirement for diagnosis. Some patients report a sensation of inspiratory difficulty, but does not necessarily discriminate patients with EILO from those without [6].

In particular, clinicians should ask patients whether the symptoms develop during exercise or after, and how quickly they resolve (seconds versus minutes), as EILO is largely associated with high work intensity and rapid resolution with cessation [24,25].

Sometimes a description of perfectionistic or anxiety-related personality features accompanies the symptoms described, although these characteristics may relate more to the pursuit of athletic performance or to the anxiety provoked by the experience, rather than being contributors to the development of EILO [26].

Physical examination — Physical examination at rest in a patient with isolated EILO is normal because, by definition, EILO is induced by exercise. There may be stigmata of coexisting diseases, such as chronic rhinitis or asthma.

Detection of stridor at rest should prompt clinicians to consider irritant-associated laryngeal obstruction (ILO) or other conditions affecting the larynx and/or trachea.

EVALUATION — EILO should be suspected in young athletes who report dyspnea with or without stridor at peak exercise. The evaluation of EILO considers other causes of exertional dyspnea, although stridor associated with exercise narrows the differential diagnosis.

Patient generated video — Some patients may struggle to describe their symptoms, as the number of lay terms for describing a variety of exertional symptoms is limited. For this reason, especially if the provider does not speak the native language of the patient, a patient-generated video using a smart phone to capture characteristic field events can be helpful in guiding the diagnostic evaluation (movie 1). As an example, it can demonstrate the rapidity of onset, duration, presence of stridor, and sometimes also hoarseness and other features.

Initial evaluation — The initial evaluation of suspected EILO is designed to assess other common causes of exertional dyspnea that may coexist with EILO or have a similar presentation to EILO. (See "Pulmonary function testing in asthma" and "Asthma in children younger than 12 years: Initial evaluation and diagnosis" and "Asthma in adolescents and adults: Evaluation and diagnosis".)

The initial evaluation generally includes spirometry with bronchodilator reversibility testing and bronchoprovocation challenge [23,27-29]. A cardiac evaluation with an electrocardiography and echocardiography is prudent prior to exercise testing in patients with a heart murmur, report of palpitations, cyanosis, chest pain, dizziness, or fainting on exertion.

Spirometry — Spirometric inspiratory and expiratory flow-volume loops (FVL) are obtained to assess airflow limitation and reversibility at rest. (See "Flow-volume loops".)

Resting FVLs are helpful in identifying processes that coexist with EILO (eg, asthma) and are in the differential diagnosis of exertional dyspnea (see 'Differential diagnosis' below). Expiratory airflow limitation, particularly if reversible with inhaled bronchodilator, would suggest asthma; fixed inspiratory airflow limitation at rest suggests extrathoracic airway obstruction, potentially due to vocal fold paralysis, vocal fold or subglottic tumor, or subglottic stenosis.

In contrast, pre and post exercise FVL are not useful for diagnosing EILO [30,31]. While occasional case reports describe post-exercise FVLs that identified inducible upper airway obstruction [28], a comparison of pre and post exercise FVLs with images from continuous laryngoscopy during exercise (CLE) did not support a general utility of FVL testing [30]. There was poor agreement among four physicians in terms of the flow-volume loop readings and no correlation between the flow-volume loop results and the CLE images.

Bronchoprovocation challenge — The main reason to perform a bronchoprovocation challenge in patients with suspected exercise-related dyspnea is to evaluate for asthma; asthma is in the differential diagnosis and patients with EILO can have concomitant asthma [18,23]. Patients who have reversible airflow limitation on spirometry meet criteria for asthma and generally do not need to undergo this step.

●Methacholine or mannitol bronchoprovocation – Methacholine or mannitol bronchoprovocation challenge is typically performed to assess airway hyperresponsiveness indicative of asthma, as it has a good, although not exact, correlation with exercise-induced bronchoconstriction (EIB). As EIB is the most common cause of exercise-related dyspnea in adolescents and young adults this is a useful initial test. In some patients with EILO, nonspecific bronchoprovocation tests provoke inspiratory laryngeal obstruction, but the correlation with EILO is imperfect [18,23,32,33]. (See "Bronchoprovocation testing".)

When using methacholine or mannitol bronchoprovocation testing to assess paradoxical vocal fold motion (PVFM) or EILO, the ratio of forced expiratory flow to forced inspiratory flow at 50 percent vital capacity (FEF50/FIF50) is used to assess decrements in inspiratory flow only if the patient develops their characteristic symptoms associated with exercise. The FEF50/FIF50 is normally <1, but with extrathoracic airflow limitation, the ratio can be >1.

The lack of correlation of this testing with EILO was demonstrated in a series of 37 adults with exertional dyspnea who underwent methacholine and mannitol challenges and CLE (see 'Continuous laryngoscopy during exercise' below) [18]. The mean decrease in forced inspiratory flow at 50 percent forced vital capacity (FIF50) did not correlate with the degree of EILO during CLE. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)".)

●Eucapnic voluntary hyperventilation with nasolaryngoscopy – Eucapnic voluntary hyperventilation (EVH) is a form of bronchoprovocation challenge that correlates closely with exercise-induced bronchoconstriction, but is less useful in the diagnosis of EILO. While preliminary studies suggest that combining EVH with nasolaryngoscopy or impulse oscillometry might help in the diagnosis of EILO, most experts (including us) believe CLE yields more dependable results [34-37]. (See "Bronchoprovocation testing", section on 'Eucapnic voluntary hyperpnea'.)

Impulse oscillometry (IOS) applies pressure waves at the mouth to measure resistance and reactance of the total respiratory system and may be more sensitive to airflow limitation than spirometry. A preliminary study suggested that IOS before and after EVH might have greater sensitivity for airway dysfunction during exercise, but the study did not compare EILO with exercise-induced bronchoconstriction [36].

Ancillary testing — Ancillary testing (eg, allergy evaluation, electrocardiogram, echocardiogram, testing for gastroesophageal or laryngopharyngeal reflux) may be appropriate based on patient demographics and specific historical information implicating other cardiorespiratory problems (eg, rhinitis, heartburn, palpitations, dizziness, chest discomfort, risk factors for coronary heart disease). (See "Approach to the patient with dyspnea".)

Continuous laryngoscopy during exercise — Continuous laryngoscopy during exercise (CLE) is considered the test of choice for EILO diagnosis based on a systematic review and a European Respiratory Society and European Laryngological Society statement [3,23,24].

Technique — CLE combines continuous flexible nasolaryngoscopy with an exercise challenge that ideally reproduces field symptoms (movie 2) [23,24,37,38]. CLE is generally performed during treadmill exercise [37] or cycle ergometry [39], but has been reported during rowing [40] and swimming [41]. Portable devices have been used in field testing [42].

A flexible laryngoscope is inserted through the nostril into the larynx at rest, enabling evaluation of the supraglottic and glottic structures. Next, the tip of the scope is positioned just above the aryepiglottic folds, and the external portion of the laryngoscope is attached to a head apparatus to hold it in place during exercise.

Importantly, any exercise protocol can be selected to best reproduce field symptoms. CLE can be performed simultaneously with the collection of metabolic data that occurs during cardiopulmonary exercise testing (CPET) to enable assessment of the work performed and potential determination of an alternate source of dyspnea if EILO is not elicited. For this reason, the exercise protocol typically follows an incremental ramp protocol on a treadmill or cycle ergometer as these protocols generate metabolic data that can be used in the assessment of other conditions. The target work rate is selected based on the provocative level of exercise described by the patient, with the intent of achieving symptoms or exhaustion within 8 to 12 minutes of loaded cycling [31]. The presence of the laryngoscope does not affect the ventilator and metabolic results of the CPET [43]. (See "Cardiopulmonary exercise testing in cardiovascular disease".)

CLE minimizes false positive (theoretically from the introduction of a laryngoscope during a time of frightening exertional dyspnea) and false negative results received from postexertional laryngoscopy, as EILO is characterized by rapid resolution of upper airway obstruction.

Laryngeal findings — As the patient gradually increases the exercise intensity, the supraglottic and glottic structures are observed for the onset of obstruction [1,31].

In patients with EILO, moderate or severe adduction of laryngeal structures develops in parallel with respiratory distress. While results vary among studies, in a series of 117 patients with EILO who underwent CLE, adduction typically started in the supraglottic structures (96 percent of patients), followed by adduction of the vocal folds (78 percent) [24]. Less than 5 percent of patients had vocal fold adduction alone or followed by supraglottic obstruction. Both glottic and supraglottic obstruction are maximal at peak exercise capacity and resolve rapidly (within seconds to minutes) after stopping exercise [25].

These findings may be minimally present at near-maximal work rates (figure 1). Critically, EILO is not an all-or-none phenomenon. There is variability among affected patients with respect to the degree of upper airway obstruction at either a glottic or supraglottic level. Predominantly vocal fold narrowing (movie 3), supraglottic narrowing (movie 4), and/or redundant obstructive supraglottic tissue (movie 5) are all potential causes of EILO that can be identified with CLE.

The degree of upper airway obstruction that defines disease has not been clearly established, but moderate obstruction is often used as a threshold [24]. Slight adduction of the aryepiglottic folds is noted at maximum minute ventilation in 40 percent of participants without respiratory complaints and is considered normal [24,44].

DIAGNOSIS — The diagnosis of EILO is based on direct visualization of supraglottic or glottic narrowing in temporal correlation with characteristic symptoms using the technique of continuous laryngoscopy during exercise (see 'Continuous laryngoscopy during exercise' above). Most often, the primary finding is medial adduction of the aryepiglottic folds during inspiration; concomitant adduction of the true vocal folds is present in a portion of patients. Less commonly, adduction of the vocal folds occurs in the absence of supraglottic narrowing.

Some patients with EILO have concomitant asthma based on reversible airflow limitation or bronchial hyperresponsiveness on bronchoprovocation challenge. (See 'Initial evaluation' above.)

Precise diagnosis of EILO is important for several reasons: Correct diagnosis can lead to specific treatment; misdiagnosis can lead to potentially harmful therapy [45]; and untreated exertional dyspnea can become a deterrent to exercise at an age when exercise is strongly advocated for its benefits to overall health [46,47].

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of exertional dyspnea is exceedingly broad and includes respiratory, cardiovascular, and neuromuscular disease as well as deconditioning. (See "Approach to the patient with dyspnea".)

The following disease processes are more specifically in the differential diagnosis of EILO.

●Exercise-induced bronchoconstriction (EIB) – In children, adolescents, and young adults, asthma is the most important and common condition in the differential diagnosis of EILO [48]. EIB in patients with asthma typically begins three minutes after exercise and peaks within 10 to 15 minutes. In contrast, dyspnea due to EILO develops at peak exercise and resolves in one to five minutes after exercise. EIB can usually be prevented by pretreatment with albuterol, which is not effective in EILO. The diagnosis of EIB is discussed separately. (See "Exercise-induced bronchoconstriction".)

●Cardiac disease – A number of cardiac processes can present with exertional dyspnea, including but not limited to hypertrophic cardiomyopathy, heart failure, coronary artery disease, pulmonary hypertension, and dysrhythmias. Consideration of cardiac disease is important as centers develop safety protocols associated with the performance of continuous laryngoscopy during exercise. (See "Approach to the patient with dyspnea" and "Cardiopulmonary exercise testing in cardiovascular disease".)

●Inducible laryngeal obstruction/paradoxical vocal fold motion – ILO/PVFM refers to an inappropriate adduction of the true vocal folds, most prominently on inspiration. ILO/PVFM results in dyspnea and stridor, not necessarily associated with exercise. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)".)

●Structural lesions of the larynx and upper trachea – Exertional stridor, when present, localizes pathology to primary and secondary conditions affecting the larger airways and includes vocal fold paralysis, subglottic stenosis, intrinsic and extrinsic lesions of the trachea, and dynamic compression of the large airways. (See "Evaluation of wheezing illnesses other than asthma in adults" and "Evaluation of wheezing in infants and children".)

●Exercise-induced anaphylaxis – Exercise-induced anaphylaxis is characterized by signs and symptoms of anaphylaxis in the setting of physical exertion. Symptoms may begin at any stage of exercise and occasionally occur just after exercise. Patients typically report systemic symptoms such as warmth, flushing, pruritus, and sometimes urticaria or syncope during exertion. (See "Exercise-induced anaphylaxis: Clinical manifestations, epidemiology, pathogenesis, and diagnosis".)

TREATMENT — The therapeutic options for EILO have not been formally studied in randomized trials. Our approach, which is in concert with guidelines [23], is to start with a speech-language pathology intervention. For patients who continue to have episodes of EILO, we suggest a more advanced form of behavioral-speech therapy using therapeutic laryngoscopy during exercise. With this technique, visual feedback is used to teach the patient to relax the muscles causing laryngeal obstruction while continuing to exercise [49].

Rare patients with primarily supraglottic obstruction who remain symptomatic after behavioral interventions may be candidates for supraglottoplasty. Medical therapies (eg, inhaled anticholinergic agents, tricyclic antidepressants, botulinum toxin) have not been sufficiently studied to be recommended. Treatment of comorbid conditions may improve associated symptoms, but is unlikely to improve EILO in the absence of other interventions.

Initial treatment with speech-behavioral therapy — Respiratory retraining delivered by a speech-language pathologist and associated behavioral interventions are considered to be the first line of therapy for EILO [3,23,50,51].

●Speech-behavioral therapy – The optimal components of speech-behavioral therapy have not been determined, but may include one or more of the following: relaxation of the oropharyngeal muscles [52], focusing on active exhalation, rhythmic breathing while making the “s” or “sh” sound [53], whole-body relaxation [50], vocal hygiene, respiratory retraining to coordinate thoracic and abdominal respiratory patterns [54], and laryngeal control therapy, which utilizes laryngoscopy during resting speech therapy [22,29,50,55]. Specific techniques that are helpful during exercise may differ from those traditionally used in inducible laryngeal obstruction (ILO)/paradoxical vocal fold motion (PVFM) diagnosed outside of exercise. The mechanisms by which the interventions provide benefit remain elusive.

One set of breathing techniques was created specifically to address the respiratory requirements multi-intensity exercise. The exercise-induced laryngeal obstruction biphasic inspiratory (EILOBI) breathing techniques were designed in response to empirical observations that abrupt changes in self-imposed airflow restriction affect the laryngeal aperture. In the initial case series describing this technique, 66 percent of patients perceived clinical effectiveness [56]. (See 'Therapeutic laryngoscopy during exercise' below.)

Evidence in favor of speech-behavioral therapy comes in part from its use in ILO/PVFM [27,29,51,52]. Approaches vary from the use of pursed lip breathing to inspiratory muscle training to more complex breathing techniques [22,50,56,57]. In a series of 56 adolescents with PVFM, voice therapy led to reduced dyspnea in over 80 percent [51]. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)", section on 'Speech-behavioral therapy'.)

Among 32 patients who had been treated with behavioral-speech therapy and were followed-up two to five years later, significant improvement was noted in a visual analog dyspnea scale from a mean of 73 to 53 [58]. Fourteen of these patients underwent repeat CLE, and laryngeal obstruction scores were overall improved and had normalized in three. Despite these improvements, approximately 40 percent had reduced their activity level because of breathing problems during exercise.

●Inspiratory muscle training – Inspiratory muscle training has been proposed as a therapy for EILO, although reported patient outcomes have been variable [59,60].

●General relaxation and psychologic support – General relaxation techniques and paced exercise are typically part of the approach [50]. In response to the observation that anxious thought patterns seem to exist among groups of EILO patients, some authors have suggested the use of general psychology or performance psychology as adjuncts [61].

Therapeutic laryngoscopy during exercise — Therapeutic laryngoscopy during exercise (TLE) uses real-time laryngoscopy as a biofeedback method to optimize motor learning involving the larynx during exercise (picture 1) [49,56]. In centers where this technique is available, we suggest therapeutic laryngoscopy during exercise in patients who have not responded to initial speech-language therapy.

The technique relies on the apparatus used for the diagnostic continuous laryngoscopy during exercise test. A nasolaryngoscope positioned in the larynx and attached to a head-piece remains in place throughout the session (see 'Technique' above). With this therapeutic procedure, patients are able to directly observe the video output from the laryngoscope. Patients are asked to perform respiratory retraining exercises during and after interval sprints which mimic real-life exercise requirements. Rest time between sprints is used to teach specific motor techniques to maximize the laryngeal aperture during inhalation. On average, two to four sessions are needed to achieve substantial improvement.

In a series of 41 patients who underwent TLE, 58 percent thought the procedure was helpful and 75 percent reported improvement in breathing during exercise [49].

Supraglottoplasty for refractory disease — Supraglottoplasty is a surgical procedure used for congenital laryngomalacia that involves laser incision of portions of the aryepiglottic folds and arytenoid towers as well as possible removal of excess mucosa (movie 5) [62,63]. For patients with EILO characterized by severe supraglottic collapse and pronounced exertional symptoms who have not improved with use of speech-language pathology intervention, we suggest supraglottoplasty [16,58,62,64,65]. Importantly, patients with EILO due to vocal fold obstruction are not candidates for supraglottoplasty.

European surgical groups have explored the use of supraglottoplasty for EILO isolated to the supraglottic level [58,62,64,65], although no randomized trials have been reported. A systematic review of surgical reports (75 patients) concluded that some results were promising, but definitive guidance for or against the procedure could not be reached given small subject numbers and methodologic differences across sites [66]. In a small study with three years of follow-up, patients who declined surgery were more likely to have persistent symptoms and decreased activity levels than those who underwent supraglottoplasty [64].

Supraglottoplasty is an irreversible procedure. Postoperative sore throat and dysphagia are common for the first one to two weeks after surgery [65]. While complications have not been reported among patients with EILO, surgical complications are possible and include laryngeal obstruction [67].

Nonstandard therapies — Medical therapies that have been suggested for use in EILO include inhaled anticholinergic agents (eg, ipratropium), oral tricyclic antidepressants, and injectable botulinum toxin, but supportive evidence is lacking [68,69].

Based on the limited and anecdotal nature of evidence [68], we do not use inhaled ipratropium for EILO. While tricyclic antidepressants have been used in a few patients with ILO/PVFM, use in EILO has not been reported. Based on the lack of supportive data and the potential for adverse reactions, this therapy is not advised for EILO.

Botulinum toxin — Botulinum toxin has been used to treat paradoxical vocal fold motion [70,71], and a case report describes a successful outcome in EILO [72], but data are insufficient to determine whether this therapy has a role in EILO.

The technique described for PVFM is to inject botulinum toxin directly into the vocal folds under local anesthesia. The rationale is that medical paralysis of the vocal folds by botulinum toxin will override dysregulated motor control of the larynx.

Treatment of comorbid diseases — Potentially important comorbid diseases (eg, asthma, rhinitis, laryngopharyngeal reflux) can affect patients with EILO and may need to be addressed simultaneously. However, evidence is lacking to support treatment of these conditions with the sole intention of improving EILO symptoms.

Approximately 10 percent of patients with EILO also have asthma and require directed treatment of asthma. (See "An overview of asthma management".)

Chronic rhinitis with postnasal drip can contribute to laryngeal sensitivity. Evaluation and treatment of chronic rhinitis can improve quality of life, even if it remains unclear whether such treatment will ameliorate EILO. (See "An overview of rhinitis".)

Similarly, laryngopharyngeal reflux can cause laryngeal irritation and should be treated if reflux is symptomatic. (See "Laryngopharyngeal reflux in adults: Evaluation, diagnosis, and management".)

Behavioral health disorders, if present, should be addressed in the overall treatment approach.

MONITORING — A patient-reported outcome measure specific to EILO called the exercise-induced laryngeal obstruction dyspnea index (EILODI) is available to monitor changes in disease severity over time and in response to interventions (table 1) [73]. The metric accounts for physical symptoms, emotional responses, and the impact of the condition. The minimal clinically important difference is 6 points.

PROGNOSIS — While long-term studies are limited, the degree of dyspnea associated with exercise improves in the majority of patients with EILO who are treated with speech-behavioral therapy and, if needed, therapeutic laryngoscopy during exercise [23,49-51]. A small portion of patients with supraglottic EILO that is refractory to these measures may improve with supraglottoplasty.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Dyspnea" and "Society guideline links: Exercise-induced bronchoconstriction".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Inducible laryngeal obstruction (ILO) (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Exercise induced laryngeal obstruction (EILO) refers to narrowing of the laryngeal airway at the glottis (vocal folds) or supraglottic level that occurs during exercise. It presents most often in adolescent and young adult athletes. (See 'Definition' above.)

●The characteristic presentation of EILO includes a history of exertional dyspnea, possibly with exertional stridor, isolated to high intensity exercise in the presence of a normal physical exam. (See 'Clinical presentation' above.)

●Evaluation of EILO often occurs in the context of a broader evaluation of exertional dyspnea and typically includes assessment of asthma and other conditions as guided by history. (See 'Evaluation' above.)

●Bronchoprovocation challenges (eg, methacholine or mannitol challenge, eucapnic voluntary hyperventilation) have not been successful at identifying EILO in the absence of an exercise stimulus, but are useful for identifying concomitant asthma. (See 'Initial evaluation' above.)

●Continuous laryngoscopy during exercise (CLE) enables laryngeal visualization during, rather than after, characteristic episodes and is considered the diagnostic test of choice (movie 2). The key finding is moderate or severe adduction of laryngeal structures that develops during exercise in parallel with respiratory distress (movie 3 and movie 4 and movie 5). (See 'Continuous laryngoscopy during exercise' above.)

●The differential diagnosis of EILO includes exercise-induced asthma, cardiac disease, structural lesions of the upper airway, and exercise-induced anaphylaxis. (See 'Differential diagnosis' above.)

●For the majority of patients with EILO, we suggest initial speech-behavioral therapy (Grade 2C). The specific components of speech-behavioral therapy that are most successful have not been determined, but generally include respiratory retraining provided by a speech-language pathologist and relaxation techniques. (See 'Initial treatment with speech-behavioral therapy' above.)

●For patients who have persistent symptoms with exercise despite speech-behavioral therapy, we suggest therapeutic laryngoscopy during exercise (Grade 2C). Real-time visual feedback during exercise is used to teach patients to prevent or control supraglottic or glottic obstruction (picture 1). (See 'Therapeutic laryngoscopy during exercise' above.)

●We reserve supraglottoplasty for patients with EILO associated with pronounced exertional symptoms and severe supraglottic collapse that has not responded to behavioral-speech therapy. (See 'Supraglottoplasty for refractory disease' above.)