Indications and Short-Term Outcomes for In-Office Therapeutic Superior Laryngeal Nerve Block

OBJECTIVE

Superior laryngeal nerve (SLN) block consists of injection of steroid and anesthetic at the internal branch of the SLN entry site. Prior case series have demonstrated beneficial effects on neurogenic cough. SLN blocks have also recently shown benefit for paralaryngeal pain. We describe short-term outcomes for multiple symptoms of irritable larynx syndrome (ILS) including neurogenic cough, dysphonia related to laryngeal hypersensitivity, inducible laryngeal obstruction (ILO), paralaryngeal pain, and isolated globus.

METHODS

Retrospective review from 2 institutions of patients undergoing a single SLN block for the indications listed. Variables include age, sex, indication(s), known vagus neuropathy, and patient-reported outcomes at short-term follow-up.

RESULTS

A total of 209 patients were included (59 males, 150 females; age: 58 ± 13 years). Twenty-six patients (12%) had a history of a vagus nerve injury. Indications included neurogenic cough (n = 149), dysphonia related to laryngeal hypersensitivity (n = 66), paralaryngeal pain (n = 50), ILO (n = 23), and isolated globus (n = 3). Some patients had multiple indications. Significant improvements in patient-reported measures occurred after a single SLN block within 2 to 4 weeks for neurogenic cough (cough severity index; 25.2 ± 11.2 to 19.0 ± 12.8; P < .001), dysphonia (voice handicap index-10; 22.1 ± 12.2-18.0 ± 13.3; P = .005), and ILO (dyspnea index; 21.0 ± 14.9-14.7 ± 15.7; P = .017). Subjective pain improved in 23 of 39 patients with paralaryngeal pain. There was no observed improvement for isolated globus. Presence of known vagal neuropathy or therapy around the time of SLN block did not affect outcome.

CONCLUSION

SLN block can be an effective component of treatment for a variety of ILS symptoms. Patients may experience some improvement after 1 injection.

LAY SUMMARY

Symptoms of irritable larynx syndrome, such as neurogenic cough, paralaryngeal pain, inducible laryngeal obstruction, and dysphonia related to laryngeal hypersensitivity can be challenging to manage. In-office Superior Laryngeal Nerve blocks can serve as a quick, well tolerated, adjunctive treatment with positive short-term outcomes.

LEVEL OF EVIDENCE

4.

Protocol for a scoping review to map health outcomes in individuals with inducible laryngeal obstruction

BACKGROUND

Inducible laryngeal obstruction causes narrowing of the laryngeal aperture in response to external triggers. Outcomes are measured in inducible laryngeal obstruction to monitor changes in health status over time.

METHODS

This study is a scoping review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. The review will be guided by the following research question: 'What health outcomes are measured in studies including people with inducible laryngeal obstruction?' The research question was validated using the Population-Concept-Context framework according to the methodology for Joanna Briggs Institution Scoping Reviews. Relevant peer-reviewed studies and grey literature conducted over the last 40 years will be identified from electronic databases including AMED, CINAHL, Embase, EMCARE, MEDLINE, OVID, PubMed and PsycINFO. The search strings 'inducible laryngeal obstruction', 'ILO', 'vocal cord dysfunction', 'VCD', 'paradoxical vocal fold motion', 'PVFM', 'outcome', 'measure', 'measurement instrument', 'assessment', 'scale', 'questionnaire' will be combined using Boolean logic. An independent reviewer will conduct title screening; two independent reviewers will conduct abstract and full article screening, followed by data extraction by two reviewers. Analyses will be conducted appropriate to the findings.

DISCUSSION

The review will document evidence of health outcomes measured in inducible laryngeal obstruction, identifying measurement characteristics and potential utility. Collating studies may identify gaps in coverage, the need for novel tools, and for standardisation for clinical and research purposes.

WHAT THIS PAPER ADDS

What is already known on the subject Inducible laryngeal obstruction causes narrowing of the laryngeal aperture in response to external triggers. Outcomes are measured in inducible laryngeal obstruction to monitor changes in health status over time. Currently, there are no standardised outcome measures for measuring the effects of interventions in inducible laryngeal obstruction (ILO). What this paper adds to existing knowledge Assessment of health can be measured in a variety of ways. Physiological, radiological and biochemical measurements of impairment are more common historically but there are a lot of outcomes of other factors now including subjective measures of functional status and health-related quality of life, with data collected directly from patients. This study will allow us to scope the literature to see the health outcomes being measured in ILO to attempt to standardise and develop future health outcomes. What are the potential or actual clinical implications of this work? The review will document evidence of health outcomes measured in inducible laryngeal obstruction, identifying measurement characteristics and potential utility. Collating studies may identify gaps in coverage, the need for novel tools and for standardisation for clinical and research purposes.

Untangling asthma, inducible laryngeal obstruction, and dysfunctional breathing in a competitive sportsperson

A young woman with historically mild asthma experienced worsening breathlessness and cough with competitive ice skating. Despite optimizing and escalating treatment for her eosinophilic asthma, and addressing known exacerbating factors, her symptoms remained uncontrolled and refractory to bronchodilators and oral corticosteroids. Objective testing suggested her presentation was out of keeping with asthma alone, and she was suspected to have comorbid dysfunctional breathing and/or inducible laryngeal obstruction. Evidence was required to confirm the diagnoses, assess each condition's contribution to her symptom burden, and guide therapy. As exercise was a predominant trigger, she proceeded to cardiopulmonary exercise test with continuous laryngoscopy during exercise (CPET-CLE). Testing confirmed the presence of two forms of inducible laryngeal obstruction and evidence of hyperventilation predominant dysfunctional breathing. This case highlights the importance of identifying coexisting conditions in difficult-to-treat asthma, and the value of structured multidisciplinary assessment in referral centres for such individuals.

Hypopharyngeal geometry impact on air-induced loads on the supraglottis

Exercise-induced laryngeal obstruction (EILO) describes paradoxical laryngeal closure during inspiration at high-intensity exercise. It is hypothesised that during intense activity, the air-induced loads on supraglottic walls overcome their internal stiffness, leading to the obstruction. Recent investigations have revealed that the air-induced loads on the supraglottic walls vary nonlinearly with increasing flow rate. It is, however, unclear whether certain geometric configurations of the hypopharynx and larynx may contribute to the predisposition to EILO. This study investigates the influence of hypopharyngeal and laryngeal geometry on upper respiratory tract airflow and air-induced forces. A computational fluid dynamics model is developed to study airflow through larynx. Four real, adult upper respiratory tracts with variable configurations are considered. Two steady, uniform inspiratory flow rates of 60 L/min and 180 L/min are considered. The analysis shows that geometries with a space lateral to the epiglottis (EpiS) and piriform fossae (PF) directs the hypopharyngeal and supraglottic pressure field to remain positive and increase with the flow rate. In geometries with EpiS and PF, pressure differential occurs around the aryepiglottic fold producing a net inward force over the region. The three-fold increase in flow rate induces near ten-fold increases in force over the region which may facilitate the closure. It is concluded that hypopharyngeal anatomy, particularly the piriform fossae, play a significant role in the obstruction of the supraglottic airway and should be considered in research and clinical assessment of EILO.

Recognizing Vocal Cord Dysfunction: Exercising Caution Before Intubation

Vocal cord dysfunction (VCD) is the inappropriate adduction of the vocal cords during inhalation and sometimes, exhalation. Vocal cord dysfunction is often misdiagnosed in the emergency room as asthma exacerbation or laryngeal angioedema, leading to unnecessary and potentially harmful interventions including intubation and mechanical ventilation. Based on this, it is especially important to recognize this condition early to avoid intubation, which can further worsen VCD. This case presents a 74-year-old female with a history of hypertension and colon cancer who presented to the emergency department (ED) with respiratory distress associated with stridor and wheezing. Our literature review sheds light on identifying key clinical features, physical exam findings, diagnostic tests, existing treatment options for this condition, and preventive measures to minimize its occurrence.

Diagnosis of vocal cord dysfunction/inducible laryngeal obstruction: An International Delphi Consensus Study

BACKGROUND

Vocal cord dysfunction/inducible laryngeal obstruction (VCD/ILO) is characterized by breathing difficulties in association with excessive supraglottic or glottic laryngeal narrowing. The condition is common and can occur independently; however, it may also be comorbid with other disorders or mimic them. Presentations span multiple specialties and misdiagnosis or delayed diagnosis is commonplace. Group-consensus methods can efficiently generate internationally accepted diagnostic criteria and descriptions to increase clinical recognition, enhance clinical service availability, and catalyze research.

OBJECTIVES

We sought to establish consensus-based diagnostic criteria and methods for VCD/ILO.

METHODS

We performed a modified 2-round Delphi study between December 7, 2021, and March 14, 2022. The study was registered at ANZCTR (Australian New Zealand Clinical Trials Registry; ACTRN12621001520820p). In round 1, experts provided open-ended statements that were categorized, deduplicated, and amended for clarity. These were presented to experts for agreement ranking in round 2, with consensus defined as ≥70% agreement.

RESULTS

Both rounds were completed by 47 international experts. In round 1, 1102 qualitative responses were received. Of the 200 statements presented to experts across 2 rounds, 130 (65%) reached consensus. Results were discussed at 2 international subject-specific conferences in June 2022. Experts agreed on a diagnostic definition for VCD/ILO and endorsed the concept of VCD/ILO phenotypes and clinical descriptions. The panel agreed that laryngoscopy with provocation is the gold standard for diagnosis and that ≥50% laryngeal closure on inspiration or Maat grade ≥2 define abnormal laryngeal closure indicative of VCD/ILO.

CONCLUSIONS

This Delphi study reached consensus on multiple aspects of VCD/ILO diagnosis and can inform clinical practice and facilitate research.

Bringing the treatable traits approach to primary care asthma management

Asthma continues to be a major cause of illness with a significant mortality, despite its increasing range of treatments. Adoption of a treatable traits approach in specialist centres has led to improvements in control of asthma and reduced exacerbations in patients with severe asthma. However, most patients with this illness, particularly those with mild-to-moderate asthma, are cared for in primary care according to guidelines that emphasise the use of pharmacotherapeutic ladders uniformly implemented across all patients. These pharmacotherapeutic ladders are more consistent with a "one-size-fits-all" approach than the treatable traits approach. This can be harmful, especially in patients whose symptoms and airway inflammation are discordant, and extra-pulmonary treatable traits are often overlooked. Primary care has extensive experience in patient-centred holistic care, and many aspects of the treatable traits approach could be rapidly implemented in primary care. Blood eosinophil counts, as a biomarker of the treatable trait of eosinophilia, are already included in routine haematology tests and could be used in primary care to guide titration of inhaled corticosteroids. Similarly, poor inhaler adherence could be further assessed and managed in primary care. However, further research is needed to guide how some treatable traits could feasibly be assessed and/or managed in primary care, for example, how to best manage patients in primary care, who are likely suffering from breathing pattern disorders and extra-pulmonary treatable traits, with frequent use of their reliever inhaler in the absence of raised T2 biomarkers. Implementation of the treatable traits approach across the disease severity spectrum will improve the quality of life of patients with asthma but will take time and research to embed across care settings.

Airflow through the supraglottis during inspiration

Exercise-induced laryngeal obstruction is a paradoxical laryngeal closure during inspiration at high-intensity exercise, with supraglottic closure being most common. This study develops a model based on the computational fluid dynamics to investigate airflow velocity and pressure and the air-induced loads on the supraglottis at various inspiratory flow rates. It is found that at high flow rates, positive wall pressure is formed in the hypopharynx localise towards its lower region, while posterior supraglottic wall pressures shift from positive to negative. These findings suggest that high inspiratory flow rates may increase supraglottic pressure differentials, ultimately contributing in the collapse.

Experiences of Diagnosis, Symptoms, and Use of Reliever Inhalers in Patients With Asthma and Concurrent Inducible Laryngeal Obstruction or Breathing Pattern Disorder: Qualitative Analysis of a UK Asthma Online Community

BACKGROUND

Breathing pattern disorders (BPDs) and inducible laryngeal obstruction (ILO) cause similar symptoms to asthma, including dyspnea and chest tightness, with an estimated prevalence of up to one-fifth of patients with asthma. Both conditions can be comorbid with asthma, and there is evidence that they are misdiagnosed and mistreated as asthma.

OBJECTIVE

This study aims to explore whether the symptoms of ILO and BPD were topics of discussion in a UK asthma online health community and patient experiences of diagnosis and treatment, in particular their use of reliever inhalers.

METHODS

A qualitative thematic analysis was performed with posts from an asthma community between 2018 and 2022. A list of key ILO or BPD symptoms was created from the literature. Posts were identified using the search terms "blue inhaler" and "breath" and included if describing key symptoms. Discussion threads of included posts were also analyzed.

RESULTS

The search retrieved a total of 1127 relevant posts: 1069 written by 302 users and 58 posted anonymously. All participants were adults, except 2 who were parents writing about their children. Sex and age were only available for 1.66% (5/302; 3 females and 2 males) and 9.93% (30/302) of participants (27 to 73 years old), respectively. The average number of posts written by each participant was 3.54 (range 1-63). Seven participants wrote >20 posts each. Participants experiencing undiagnosed ILO or BPD symptoms, whether or not comorbid with asthma, expressed frustration with the "one-size-fits-all" approach to diagnosis, as many felt that their asthma diagnosis did not fully explain symptoms. Some suspected or were formally diagnosed with BPD or ILO, the latter reporting relief on receiving a diagnosis and appropriate management. Participants showed awareness of their inappropriate salbutamol use or overuse due to lack of effect on symptoms. BPD and ILO symptoms were frequently comorbid with asthma. The asthma online community was a valuable resource: engagement with peers not only brought comfort but also prompted action with some going back to their clinicians and reaching a diagnosis and appropriate management.

CONCLUSIONS

Undiagnosed ILO and BPD symptoms and lack of effects of asthma treatment were topics of discussion in an asthma online community, caused distress and frustration in participants, and affected their relationship with health care professionals, showing that patients experiencing BPD and ILO have unmet needs. Clinicians' education on BPD and ILO diagnosis and management, as well as increased access to appropriate management options, such as respiratory physiotherapy and speech and language therapy, are warranted particularly in primary care. Qualitative evidence that engagement with the online community resulted in patients taking action going back to their clinicians and reaching a diagnosis of ILO and BPD prompts future research on online peer support from an established online health community as a self-management resource for patients.

Paradoxical Vocal Fold Dysfunction Mimicking Bronchial Asthma in a Young Female Patient

Inducible laryngeal obstruction (ILO)/paradoxical vocal fold motion (PVFM) is a reversible narrowing of the larynx that results from vocal fold motion dysfunction. Distinguishing ILO from asthma can be challenging, as they can coexist, and standard tests may not be able to differentiate between the two. However, a flexible laryngoscopy can promptly diagnose ILO. Unfortunately, ILO is often overlooked as a potential cause when evaluating patients with sudden-onset breathing difficulties and respiratory distress. We present a case of a young female who sought frequent treatment at the emergency room (ER) with symptoms of shortness of breath (SOB), rapid heart rate, rapid breathing, and anxiety. Despite receiving treatment for acute asthma attacks, her symptoms persisted. During her most recent hospital admission, a flexible laryngoscopy revealed abnormal vocal fold movements, indicating paradoxical vocal fold dysfunction (PVFD) and muscle tension dysphonia (MTD). A comprehensive treatment approach involving speech therapy, pulmonology, and psychiatry led to significant clinical improvement. This case report highlights the importance of raising awareness among healthcare providers about ILO potentially mimicking bronchial asthma exacerbation.

Vocal cord dysfunction/inducible laryngeal obstruction-2022 Melbourne Roundtable Report

Vocal cord dysfunction/inducible laryngeal obstruction (VCD/ILO), is a common condition characterized by breathlessness associated with inappropriate laryngeal narrowing. Important questions remain unresolved, and to improve collaboration and harmonization in the field, we convened an international Roundtable conference on VCD/ILO in Melbourne, Australia. The aims were to delineate a consistent approach to VCD/ILO diagnosis, appraise disease pathogenesis, outline current management and model(s) of care and identify key research questions. This report summarizes discussions, frames key questions and details recommendations. Participants discussed clinical, research and conceptual advances in the context of recent evidence. The condition presents in a heterogenous manner, and diagnosis is often delayed. Definitive diagnosis of VCD/ILO conventionally utilizes laryngoscopy demonstrating inspiratory vocal fold narrowing >50%. Computed tomography of the larynx is a new technology with potential for swift diagnosis that requires validation in clinical pathways. Disease pathogenesis and multimorbidity interactions are complex reflecting a multi-factorial, complex condition, with no single overarching disease mechanism. Currently there is no evidence-based standard of care since randomized trials for treatment are non-existent. Recent multidisciplinary models of care need to be clearly articulated and prospectively investigated. Patient impact and healthcare utilization can be formidable but have largely escaped inquiry and patient perspectives have not been explored. Roundtable participants expressed optimism as collective understanding of this complex condition evolves. The Melbourne VCD/ILO Roundtable 2022 identified clear priorities and future directions for this impactful condition.

[A CASE OF INDUCIBLE LARYNGEAL OBSTRUCTION UNSUCCESSFULLY TREATED AS SEVERE ASTHMA WAS WELL CONTROLLED AFTER APPROPRIATE DIAGNOSIS AND INSTRUCTION OF THERAPEUTIC BREATHING MANEUVERS]

BACKGROUND

Inducible laryngeal obstruction (ILO) refers to respiratory disorders caused by airflow limitation in the larynx, including vocal cord dysfunction, and may sometimes be misdiagnosed as bronchial asthma (BA). Here, we report the case of an 11-year-old boy diagnosed with BA in infancy. He was referred to our Allergy Center and was taking a high dose of inhaled corticosteroids (ICS) due to frequent coughing from the age of 10 years and persistent coughing following COVID-19 infection at the age of 11. However, the patient continued to experience frequent coughing attacks and repeated visits to the emergency department after inhalation of β₂-stimulants failed to improve his cough. We admitted him to the allergy center for examinations to assess the BA severity. In the airway hypersensitiveness test, saline inhalation performed prior to methacholine inhalation caused expiratory stridor and respiratory distress in the larynx, which worsened with β₂-stimulant inhalation. Based on these results, we ruled out BA and diagnosed ILO. We instructed him on breathing maneuvers, and he was able to respond appropriately when symptoms appeared. We then started reducing his ICS dose.

Paroxysmal dyspnoea in asthma: Wheeze, ILO or dysfunctional breathing?

Paroxysms of dyspnoea in the general population are commonly reported and are frequently assumed to be asthma-related, especially if this diagnostic label has been previously applied. Often, this is not the case. Inducible Laryngeal Obstruction (ILO) and Dysfunctional Breathing (DB) are common comorbid conditions that go unrecognised in many difficult-to-treat asthmatics. On average, these patients have a delay in diagnosis of almost 5 years. This delay, along with ineffective, inappropriate escalation of asthma therapy, frequent hospital presentations for uncontrolled symptoms, and even intensive care admissions, magnifies patient morbidity and poor quality of life. ILO and DB have similar presentations and triggers to asthma. Differentiating between them can be challenging, especially in centres that do not have access to multidisciplinary subspecialty asthma services. Objectively confirming the diagnosis can likewise be challenging as symptoms fluctuate, and gold-standard investigations require extensive experience. This mini-review will summarise the clinical features of ILO and DB, with particular focus in the context of individuals treated for asthma. This narrative review will define each condition, highlight poignant aspects of the history and describe elements of the diagnostic pathway to gain objective confirmation.

The impact of identifying laryngeal obstruction syndromes on reducing treatment of pediatric asthma: A systematic review

Inducible laryngeal obstruction (ILO) in children is underrecognized. This systematic review characterizes the scientific evidence on the impact of pediatric ILO diagnosis and treatment on asthma medication use. This review, registered with PROSPERO (CRD42020209168), utilized database searches in MEDLINE, EMBASE, CINAHL, and Web of Science from inception to October 2020. Both experimental and observational studies on ILO and asthma outcomes in patients ≤18 years were included. Population characteristics (sample size, sex, age, and comorbidities) and study outcomes (medication usage and respiratory symptoms) were extracted. The risk of bias was assessed with the National Toxicology Program's Office of Health Assessment and Risk of Bias Rating Tool. Data are presented narratively due to study heterogeneity. Of 1091 studies, 1076 titles and abstracts were screened after duplicate removal. Screening 31 full texts yielded eight pre-post studies. Patients were an average of 14.1 years old, 15% male, and >90% used asthma medication; 40% reported allergies, 30% gastroesophageal reflux, and 20% anxiety or depression. Most patients received at least one intervention, with 75% showing symptomatic improvement and >75% decreasing or stopping asthma medications. Studies were small with a high risk of selection, confounding, and detection bias. Asthma management was not a primary outcome in any of the studies. Overall, ILO patients were often diagnosed with or treated for asthma before ILO diagnosis. Evidence from individual studies suggests that comorbidities including ILO, gastroesophageal reflux, allergies, and anxiety should be considered in pediatric patients with asthma not responsive to medical therapy. Further research is required to determine the proportion of impacted asthma patients.

Prevalence of inducible laryngeal obstruction among patients diagnosed as bronchial asthma

INTRODUCTION

Inducible laryngeal obstruction (ILO) is an important cause of a variety of respiratory symptoms and can mimic bronchial asthma (BA). This study was planned to measure the prevalence of ILO among patients diagnosed with BA and to detect its effect on BA control and severity.

MATERIAL AND METHODS

Patients aged 18 years or older who were previously diagnosed with BA were enrolled. Laryngeal obstruction was induced using the patient's specific trigger (e.g. exercise). Visualization of vocal folds was accomplished using a 70-degree rigid laryngoscope (Karl Storz). A visual grade score was utilized to determine the severity of laryngeal obstruction.

RESULTS

Results showed that 38.3% (n = 46) of the patients had ILO with the majority being classified as grade 2 (80.4%) (n = 37). The most common subtype was glottic ILO (63%). Bronchial asthma duration, level of control, and severity were not associated with ILO (P values: 0.2, 0.3 and 0.8 respectively).

CONCLUSION

Asthma and ILO commonly co-exist. An accurate classification of patients is very important and must be considered in order to determine whether the symptoms are directly related to ILO or whether they are caused by BA. Ceasing inappropriate treatment may be necessary. Objective diagnostic modalities of ILO are essential.

UK consensus statement on the diagnosis of inducible laryngeal obstruction in light of the COVID-19 pandemic

Prior to the COVID‐19 pandemic, laryngoscopy was the mandatory gold standard for the accurate assessment and diagnosis of inducible laryngeal obstruction. However, upper airway endoscopy is considered an aerosol‐generating procedure in professional guidelines, meaning routine procedures are highly challenging and the availability of laryngoscopy is reduced. In response, we have convened a multidisciplinary panel with broad experience in managing this disease and agreed a recommended strategy for presumptive diagnosis in patients who cannot have laryngoscopy performed due to pandemic restrictions. To maintain clinical standards whilst ensuring patient safety, we discuss the importance of triage, information gathering, symptom assessment and early review of response to treatment. The consensus recommendations will also be potentially relevant to other future situations where access to laryngoscopy is restricted, although we emphasize that this investigation remains the gold standard.

Hemi-laryngopharyngeal Spasm (HeLPS): Defining a New Clinical Entity

OBJECTIVE

Hemi-laryngopharyngeal spasm (HeLPS) has recently been described in the neurosurgical literature as a cause of intermittent laryngopharyngeal spasm and cough due to vascular compression of the vagus nerve at the cerebellopontine angle. We present the diagnostic criteria for this syndrome.

METHODS

A retrospective chart review of six patients with HeLPS and three patients misdiagnosed with this condition are presented. All patients were diagnosed and treated at a tertiary care academic centre from July 2013 to July 2017.

RESULTS

Patients with HeLPS had five defining characteristics: 1) All patients had symptoms of episodic laryngopharyngeal spasm and coughing. Patients were asymptomatic between episodes and were refractory to speech therapy and reflux management. 2) Laryngoscopy showed hyperactive twitching of the ipsilateral vocal fold in two of the six patients. No other inter-episodic abnormalities were seen. 3) Botulinum toxin A injections into the thyroarytenoid muscle on the affected ipsilateral side reduced laryngopharyngeal spasms. Botulinum toxin injection in the contralateral thyroarytenoid muscle did not improve laryngopharyngeal spasm. 4) Magnetic resonance imaging revealed ipsilateral neurovascular compression of the vagus nerve rootlets by the posterior inferior cerebellar artery. 5) Microvascular decompression (MVD) surgery of the ipsilateral vagus nerve resolved all symptoms (follow-up 2-4 years).

CONCLUSION

The diagnostic criteria for hemi-laryngopharyngeal spasm (HeLPS) are proposed. Otolaryngology recognition of this new clinical entity may lead to a surgical cure and avoid the unnecessary therapies associated with misdiagnosis.

LEVEL OF EVIDENCE

4.

Prevalence and impact of comorbid laryngeal dysfunction in asthma: A systematic review and meta-analysis

BACKGROUND

Laryngeal or vocal cord dysfunction has long been regarded as a mimic of asthma; however, recent evidence indicates that it may be a significant comorbid condition in patients with asthma.

OBJECTIVE

We aimed to systematically estimate the prevalence of comorbid laryngeal dysfunction (LD) in adults with asthma and characterize its clinical impact on asthma.

METHODS

Electronic databases were searched for relevant studies published until June 2019. Studies were included if LD was objectively defined by direct visualization of laryngeal movement. Outcomes included the prevalence of LD and its association with clinical asthma indicators, such as severity, control, and quality of life. Random effects meta-analyses were performed to calculate the estimates.

RESULTS

A total of 21 studies involving 1637 patients were identified. Overall, the pooled prevalence of LD in adults with asthma was 25% (95% CI = 15%-37%; I² = 96%). Prevalence estimates differed according to the diagnostic test utilized, with the lowest overall prevalence (4% [95% CI = 0%-10%; I² = 90%]) seen when LD was diagnosed by resting laryngoscopy without external stimuli; however, it was much higher when diagnosed by laryngoscopy studies utilizing an external trigger, such as exercise (38% [95% CI = 24%-53%; I² = 90%]) or in studies using a computed tomography-based diagnostic protocol (36% [95% CI = 24%-49%; I² = 78%]). Only 7 studies reported the associations between LD and clinical asthma indicators; inconsistencies between studies limited meaningful conclusions.

CONCLUSION

LD may be a common comorbidity in asthma, affecting about 25% of adult patients. Further prospective studies are needed to better characterize its clinical impact and the benefits of detecting and managing LD in patients with asthma.

Pediatric Dysfunctional Breathing: Proposed Components, Mechanisms, Diagnosis, and Management

Dysfunctional breathing (DB) is an overarching term describing deviations in the normal biomechanical patterns of breathing which have a significant impact on quality of life, performance and functioning. Whilst it occurs in both children and adults, this article focuses specifically on children. DB can be viewed as having two components; breathing pattern disorder (BPD) and inducible laryngeal obstruction (ILO). They can be considered in isolation, however, are intricately related and often co-exist. When both are suspected, we propose both BPD and ILO be investigated within an all-encompassing multi-disciplinary dysfunctional breathing clinic. The MDT clinic can diagnose DB through expert history taking and a choice of appropriate tests/examinations which may include spirometry, breathing pattern analysis, exercise testing and laryngoscopic examination. Use of the proposed algorithm presented in this article will aid decision making regarding choosing the most appropriate tests and understanding the diagnostic implications of these tests. The most common symptoms of DB are shortness of breath and chest discomfort, often during exercise. Patients with DB typically present with normal spirometry and an altered breathing pattern at rest which is amplified during exercise. In pediatric ILO, abnormalities of the upper airway such as cobblestoning are commonly seen followed by abnormal activity of the upper airway structures provoked by exercise. This may be associated with a varying degree of stridor. The symptoms, however, are often misdiagnosed as asthma and the picture can be further complicated by the common co-presentation of DB and asthma. Associated conditions such as asthma, extra-esophageal reflux, rhinitis, and allergy must be treated appropriately and well controlled before any directed therapy for DB can be started if therapy is to be successful. DB in pediatrics is commonly treated with a course of non-pharmaceutical therapy. The therapy is provided by an experienced physiotherapist, speech and language therapist or psychologist depending on the dominant features of the DB presentation (i.e., BPD or ILO in combination or in isolation) and some patients will benefit from input from more than one of these disciplines. An individualized treatment program based on expert assessment and personalized goals will result in a return to normal function with reoccurrence being rare.

Heliox for inducible laryngeal obstruction (vocal cord dysfunction): A systematic literature review

OBJECTIVES

To perform a systematic literature review on the use of Heliox with patients with inducible laryngeal obstruction/vocal cord dysfunction to: i) identify current evidence base; and ii) establish the methodological quality of published research.

METHODS

Articles published up to March 2018 were searched for key words and terms using Cochrane Library, MEDLINE, PubMed, CINAHL, EMBASE and Dynamed. Studies were included if they presented original research into the use of Heliox for vocal cord dysfunction.

RESULTS

Only three studies met the inclusion criteria for review. All reported favorable results for the use of Heliox as an adjunctive therapy for vocal cord dysfunction but none had sufficient methodological quality to support their conclusions.

CONCLUSION

Despite review articles recommending the use of Heliox in vocal cord dysfunction, there is a lack of good quality research to support this conclusion. There is a need for further research to investigate the effectiveness of Heliox as an adjunctive therapy for vocal cord dysfunction.

LEVEL OF EVIDENCE

4.

Hemi-laryngopharyngeal spasm as a novel cause of inducible laryngeal obstruction with a surgical cure: report of 3 cases

Inducible laryngeal obstruction has been described under at least 40 different monikers, including vocal cord dysfunction, paroxysmal vocal fold motion, and irritable larynx. The etiology of this condition is believed to be laryngeal hyperactivity in response to psychological issues or acid reflux. Most patients are treated with some combination of proton pump inhibitors, speech therapy, and psychotherapy. However, a small cohort of patients remains refractory to all medical interventions. The authors describe a novel condition, hemi-laryngopharyngeal spasm (HELPS), which can cause severe episodic stridor leading to unconsciousness in association with cough. The first recognized and surgically cured patient with HELPS was reported in an earlier issue of this journal. Three additional patients have been followed up for at least a year postoperatively, and their cases are reported here.Each patient presented with a similar pattern of episodic coughing and choking that increased in frequency, severity, and duration over years. The episodes eventually occurred while sleeping and could cause severe stridor with loss of consciousness. All three patients were initially misdiagnosed with a psychiatric illness and subjected to multiple intubations and one tracheostomy. Unilateral botulinum toxin injections in the vocal fold eased the severity of the throat contractions but not the cough. Magnetic resonance imaging showed a looping posterior inferior cerebellar artery juxtaposed to a vagus nerve in each case. Microvascular decompression (MVD) of that vessel relieved all symptoms.The introduction of this new medical condition may help a small cohort of patients with inducible laryngeal obstructions that have not responded to the current standard treatments. Patients are asymptomatic between episodes of progressively severe coughing and choking with stridor that may lead to intubation. Severe anxiety about the unpredictable symptoms is expected and may contribute to a psychiatric misdiagnosis. Microvascular decompression for HELPS is more difficult than that for trigeminal neuralgia because the involved nerve is more susceptible to manipulation. Ultimately, the final proof that HELPS is a real and distinct syndrome will require its recognition and successful treatment by colleagues around the world.

Diagnosis of concomitant inducible laryngeal obstruction and asthma

BACKGROUND

Inducible laryngeal obstruction, an induced, inappropriate narrowing of the larynx, leading to symptomatic upper airway obstruction, can coexist with asthma. Accurate classification has been challenging because of overlapping symptoms and the absence of sensitive diagnostic criteria for either condition.

OBJECTIVE

To evaluate patients with concomitant clinical suspicion for inducible laryngeal obstruction and asthma. We used a multidisciplinary protocol incorporating objective diagnostic criteria to determine whether asthma, inducible laryngeal obstruction, both, or neither diagnosis was present.

METHODS

Consecutive patients were prospectively assessed by a laryngologist, speech pathologist and respiratory physician. Inducible laryngeal obstruction was diagnosed by visualizing paradoxical vocal fold motion either at baseline or following mannitol provocation. Asthma was diagnosed by physician assessment with objective variable airflow obstruction. Validated questionnaires for laryngeal dysfunction and relevant comorbidities were administered.

RESULTS

Of 69 patients, 15 had asthma alone, 11 had inducible laryngeal obstruction alone and 14 had neither objectively demonstrated. Twenty-nine patients had both diagnoses. In 19 patients, inducible laryngeal obstruction was only seen following provocation. Among patients with inducible laryngeal obstruction, chest tightness was more frequent with concurrent asthma. Among patients with asthma, stridor was more frequent with concurrent inducible laryngeal obstruction. Cough was more frequently found in asthma alone, whereas difficulty with inspiration and symptoms triggered by psychological stress were more frequently found in inducible laryngeal obstruction alone. Patients with asthma alone had greater airflow obstruction. Relevant comorbidities were frequent (rhinitis in 85%, gastro-oesophageal reflux in 65%), and questionnaire scores for laryngeal dysfunction were abnormal. However, neither comorbidities nor questionnaires differentiated patients with or without inducible laryngeal obstruction.

CONCLUSIONS AND CLINICAL RELEVANCE

In this cohort with suspected inducible laryngeal obstruction and asthma, 42% had objective evidence of both conditions. Clinical assessment, questionnaire scores and comorbidity burden were not sufficiently discriminatory for diagnosis, highlighting the necessity of objective diagnostic testing.

Dysfunctional Breathing in Children and Adults With Asthma

Asthma occurs across the life course. Its optimal treatment includes the use of personalized management plans that recognize the importance of co-morbidities including so-called "dysfunctional breathing." Such symptoms can arise as a result of induced laryngeal obstruction (ILO) or alterations in the mechanics of normal breathing called breathing pattern disorders. Whilst these two types of breathing abnormalities might be related, studies tend to focus on only one of them and do not consider their relationship. Evidence for these problems amongst childhood asthmatics is largely anecdotal. They seem rare in early childhood. Both types are more frequently recognized in the second decade of life and girls are affected more often. These observations tantalizingly parallel epidemiological studies characterizing the increasing prevalence and severity of asthma that also occurs amongst females after puberty. Exercise ILO is more common amongst adolescents and young adults. It should be properly delineated as it might be causally related to specific treatable factors. More severe ILO occurring at rest and breathing pattern disorders are more likely to be occurring within a psychological paradigm. Dysfunctional breathing is associated with asthma morbidity through a number of potential mechanisms. These include anxiety induced breathing pattern disorders and the enhanced perception of subsequent symptoms, cooling and drying of the airways from hyperventilation induced hyperresponsiveness and a direct effect of emotional stimuli on airways constriction via cholinergic pathways. Hyperventilation is the most common breathing pattern disorder amongst adults. Although not validated for use in asthma, the Nijmegen questionnaire has been used to characterize this problem. Studies show higher scores amongst women, those with poorly controlled asthma and those with psychiatric problems. Evidence that treatment with breathing retraining techniques is effective in a primary care population including all types of asthmatics suggests the problem might be more ubiquitous than just these high-risk groups. Future challenges include the need for studies characterizing all types of dysfunctional breathing in pediatric and adult patient cohorts and clearly defined, age appropriate, interventional studies. Clinicians caring for asthmatics in all age groups need to be aware of these co-morbidities and routinely ask about symptoms that suggest these problems.

Differentiating vocal cord dysfunction from asthma

Vocal cord dysfunction (VCD)-associated symptoms are not rare in pediatric patients. Dyspnea, wheezing, stridor, chest pain or tightness and throat discomfort are the most commonly encountered symptoms. They may occur either at rest or more commonly during exercise in patients with VCD, as well as in asthmatic subjects. The phase of respiration (inspiration rather than expiration), the location of the wheezing origin, the rapid resolution of symptoms, and the timing occurring in relation to exercise, when VCD is exercise induced, raise the suspicion of VCD in patients who may have been characterized as merely asthmatics and, most importantly, had not responded to the appropriate treatment. The gold standard method for the diagnosis of VCD is fiberoptic laryngoscopy, which may also identify concomitant laryngeal abnormalities other than VCD. However, as VCD is an intermittent phenomenon, the procedure should be performed while the patient is symptomatic. For this reason, challenges that induce VCD symptoms should be performed, such as exercise tests. Recently, for the evaluation of patients with exercise-induced VCD, continuous laryngoscopy during exercise (such as treadmill, bicycle ergometer, swimming) was used. A definite diagnosis of VCD is of importance, especially for those patients who have been erroneously characterized as asthmatics, without adequate response to treatment. In these cases, another therapeutic approach is necessary, which will depend on whether they suffer solely from VCD or from both conditions.

Inducible laryngeal obstruction during exercise: moving beyond vocal cords with new insights

Exercise as an important part of life for the health and wellness of children and adults. Inducible laryngeal obstruction (ILO) is a consensus term used to describe a group of disorders previously called vocal cord dysfunction, paradoxical vocal fold motion, and numerous other terms. Exercise-ILO can impair one's ability to exercise, can be confused with asthma, leading to unnecessary prescription of asthma controller and rescue medication, and results in increased healthcare resource utilization including (rarely) emergency care. It is characterized by episodic shortness of breath and noisy breathing that generally occurs at high work rates. The present diagnostic gold standard for all types of ILO is laryngoscopic visualization of inappropriate glottic or supraglottic movement resulting in airway narrowing during a spontaneous event or provocation challenge. A number of different behavioral techniques, including speech therapy, biofeedback, and cognitive-behavioral psychotherapy, may be appropriate to treat individual patients. A consensus nomenclature, which will allow for better characterization of patients, coupled with new diagnostic techniques, may further define the epidemiology and etiology of ILO as well as enable objective evaluation of therapeutic modalities.