Biology:Exercise-induced laryngeal obstruction

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Exercise-induced laryngeal obstruction (EILO) is a transient, reversible narrowing of the larynx that occurs during high intensity exercise. This acts to impair airflow and cause shortness of breath, stridor and often discomfort in the throat and upper chest. EILO is a very common cause of breathing difficulties in young athletic individuals but is often misdiagnosed as asthma or exercise-induced bronchoconstriction.[1][2]

Causes

EILO may arise because of a relative mechanical 'insufficiency' of the laryngeal structures that should act to maintain glottic patency. It has been proposed that a narrowing at the laryngeal inlet during the state of high airflow (e.g. when running fast), can act to cause a pressure drop across the larynx which then acts to 'pull' the laryngeal structures together. The Bernoulli principle states that increasing airflow through a tube creates increasing negative pressures within that tube.[3] Complex neuromuscular functioning is required to maintain laryngeal opening and to allow the larynx to achieve a great number of tasks (i.e. speaking, airway protection, swallowing).[4] It is thus also possible that EILO may arise as form a degree of neuromuscular failure.

A small heredity study indicated that an autosomal dominant model of inheritance with variable expressivity and reduced penetrance in males may be relevant; because in ten families studied, there was at least one affected person in every generation in which both parents were examined.[5] Further work is needed to determine if structural deficiencies in the laryngeal tissue of individuals with EILO are present.

Mechanism

EILO is typically caused by a narrowing of the supra-glottic structures of the larynx. In severe cases, these structures, also called arytenoids, can close over to almost completely close the laryngeal inlet. In fewer cases, the glottic (i.e. vocal cord) structures close together and this is typically what happens during exercise-induced vocal-cord dysfunction. EILO develops during intense exercise and closure develops as exercise becomes more intense.[6] Closure of the voice box during exercise causes increased 'loading' on the breathing system and the respiratory muscles have to work much harder.[7]

Epidemiology

The prevalence of EILO in adolescents and young adults appears to be in the range of 5–7% in northern Europe.[8][9] Some, but not all studies report a higher female prevalence. Thus, in a study of 94 patients diagnosed using the CLE test, average age was ∼15 years, and 68% were female.[10]

In athletic individuals EILO appears to be a highly prevalent cause of cough and wheeze and can co-exist with EIB. In one study, of almost 90 athletes, with unexplained respiratory symptoms, EILO was found to be present in approximately 30% of athletes, whilst EILO and EIB co-existed in one in ten.[11] This condition can co-exist with other conditions, including severe asthma.[12]

Clinical features

  • Key clinical features often include:[13]
    • Difficulty 'catching a breath'
    • Wheeze or whistling sound; typically when breathing in when exercising hard
    • Throat or upper chest discomfort
  • Symptoms often start to improve from the time of exercise cessation / reducing exercise intensity
  • No improvement with standard asthma medication (e.g. salbutamol, albuterol).

Diagnosis

The current gold-standard means for diagnosing EILO is the continuous laryngoscopy during exercise test (CLE-test). This test involves the placement of a flexible laryngoscope via nostril, which is then secured in place and held with head-gear. It allows continuous visualization of the laryngeal aperture during exercise. The CLE test can be used during indoor treadmill or cycle-ergometer exercise but also whilst rowing or swimming[14] or exercising outdoors[15]

The examiner visually evaluates the relative change of the laryngeal inlet in the patien throughout the CLE-test. One common grading system uses 4 steps (0-3) on glottic and supraglottic level respectively. Grades 0-1 are considered normal, whereas grades 2-3 on either or both levels are consistent with EILO.[16] There is a need to identify other less-invasive means of making a secure diagnosis.

Treatment

The current mainstay of treatment is therapy-based. Specialist breathing techniques, most commonly termed biphasic breathing techniques or EILOBI are recommended to reduce turbulent inspiratory airflow and thus reduce chance of laryngeal closure.[17]

Direct laryngeal visualisation during exercise to deliver biofeedback has been employed with success.[citation needed]

The place of inspiratory muscle training (IMT) is yet to be defined in EILO therapy.

Surgical treatment with supraglottopasty has also been utilised with success.[18]

Avoiding unnecessary treatment with asthma inhalers is important.[citation needed]

References

  1. ↑ Hall, A.; Thomas, M.; Sandhu, G.; Hull, J. H. (25 August 2016). "Exercise-induced laryngeal obstruction: a common and overlooked cause of exertional breathlessness". British Journal of General Practice 66 (650): e683–e685. doi:10.3399/bjgp16X687001. PMID 27563141. 
  2. ↑ Halvorsen, Thomas; Walsted, Emil Schwarz; Bucca, Caterina et al. (9 September 2017). "Inducible laryngeal obstruction: an official joint European Respiratory Society and European Laryngological Society statement". European Respiratory Journal 50 (3): 1602221. doi:10.1183/13993003.02221-2016. PMID 28889105. 
  3. ↑ Røksund, Ola Drange; Heimdal, John-Helge; Olofsson, Jan; Maat, Robert Christiaan; Halvorsen, Thomas (2015). "Larynx during exercise: the unexplored bottleneck of the airways". European Archives of Oto-Rhino-Laryngology 272 (9): 2101–2109. doi:10.1007/s00405-014-3159-3. PMID 25033930. 
  4. ↑ Hull, James H.; Backer, Vibeke; Gibson, Peter G.; Fowler, Stephen J. (2016-11-01). "Laryngeal Dysfunction: Assessment and Management for the Clinician". American Journal of Respiratory and Critical Care Medicine 194 (9): 1062–1072. doi:10.1164/rccm.201606-1249CI. PMID 27575803. https://www.research.manchester.ac.uk/portal/en/publications/laryngeal-dysfunction(1dee70f4-ca6a-4a40-be0e-1083b9b9f46e).html. 
  5. ↑ Walsted, Emil Schwarz; Hvedstrup, Jeppe; Eiberg, Hans; Backer, Vibeke (August 2017). "Heredity of supraglottic exercise-induced laryngeal obstruction". The European Respiratory Journal 50 (2): 1700423. doi:10.1183/13993003.00423-2017. PMID 28818875. 
  6. ↑ Olin, J. Tod; Clary, Matthew S.; Fan, Elizabeth M.; Johnston, Kristina L.; State, Claire M.; Strand, Matthew; Christopher, Kent L. (October 2016). "Continuous laryngoscopy quantitates laryngeal behaviour in exercise and recovery". The European Respiratory Journal 48 (4): 1192–1200. doi:10.1183/13993003.00160-2016. PMID 27418554. 
  7. ↑ Walsted, Emil Schwarz; Faisal, Azmy; Jolley, Caroline J.; Swanton, Laura L.; Pavitt, Matthew J.; Luo, Yuan-Ming; Backer, Vibeke; Polkey, Michael I. et al. (2017-11-02). "Increased respiratory neural drive and work of breathing in exercise-induced laryngeal obstruction". Journal of Applied Physiology 124 (2): 356–363. doi:10.1152/japplphysiol.00691.2017. PMID 29097629. 
  8. ↑ Johansson, Henrik; Norlander, Katarina; Berglund, Lars; Janson, Christer; Malinovschi, Andrei; Nordvall, Lennart; Nordang, Leif; Emtner, Margareta (January 2015). "Prevalence of exercise-induced bronchoconstriction and exercise-induced laryngeal obstruction in a general adolescent population". Thorax 70 (1): 57–63. doi:10.1136/thoraxjnl-2014-205738. PMID 25380758. 
  9. ↑ Christensen, Pernille M.; Thomsen, S. F.; Rasmussen, N.; Backer, V. (September 2011). "Exercise-induced laryngeal obstructions: prevalence and symptoms in the general public". European Archives of Oto-rhino-laryngology 268 (9): 1313–1319. doi:10.1007/s00405-011-1612-0. PMID 21528411. 
  10. ↑ Maat, Robert Christiaan; Hilland, Magnus; Røksund, Ola Drange; Halvorsen, Thomas; Olofsson, Jan; Aarstad, Hans Jørgen; Heimdal, John-Helge (October 2011). "Exercise-induced laryngeal obstruction: natural history and effect of surgical treatment". European Archives of Oto-rhino-laryngology 268 (10): 1485–1492. doi:10.1007/s00405-011-1656-1. PMID 21643933. 
  11. ↑ Nielsen, Emil Walsted; Hull, James H.; Backer, Vibeke (November 2013). "High prevalence of exercise-induced laryngeal obstruction in athletes". Medicine and Science in Sports and Exercise 45 (11): 2030–2035. doi:10.1249/MSS.0b013e318298b19a. PMID 23657163. 
  12. ↑ Hull, James H.; Walsted, Emil S.; Pavitt, Matt J.; Menzies-Gow, Andrew; Backer, Vibeke; Sandhu, Guri (2019-02-15). "High Prevalence of Laryngeal Obstruction during Exercise in Severe Asthma". American Journal of Respiratory and Critical Care Medicine 199 (4): 538–542. doi:10.1164/rccm.201809-1734LE. ISSN 1073-449X. PMID 30570393. 
  13. ↑ Griffin, Steffan Arthur; Walsted, Emil S; Hull, James H (September 2018). "Breathless athlete: exercise-induced laryngeal obstruction". British Journal of Sports Medicine 52 (18): 1211–1212. doi:10.1136/bjsports-2018-099159. ISSN 0306-3674. PMID 29669719. 
  14. ↑ Walsted, Emil S.; Swanton, Laura L.; van van Someren, Ken; Morris, Tessa E.; Furber, Matthew; Backer, Vibeke; Hull, James H. (October 2017). "Laryngoscopy during swimming: A novel diagnostic technique to characterize swimming-induced laryngeal obstruction: Laryngoscopy During Swimming". The Laryngoscope 127 (10): 2298–2301. doi:10.1002/lary.26532. PMID 28236311. 
  15. ↑ Hull, James H.; Walsted, Emil S.; Orton, Christopher M.; Williams, Parris; Ward, Simon; Pavitt, Mathew J. (February 2019). "Feasibility of portable continuous laryngoscopy during exercise testing". ERJ Open Research 5 (1): 00219–2018. doi:10.1183/23120541.00219-2018. ISSN 2312-0541. PMID 30740460. 
  16. ↑ Halvorsen, Thomas; Skadberg, Britt Torunn; Olofsson, Jan; Heimdal, John Helge; Maat, Robert Christiaan; Røksund, Ola Drange (2009-12-01). "Exercise induced dyspnea in the young. Larynx as the bottleneck of the airways" (in English). Respiratory Medicine 103 (12): 1911–1918. doi:10.1016/j.rmed.2009.05.024. ISSN 0954-6111. PMID 19782550. https://www.resmedjournal.com/article/S0954-6111(09)00187-5/abstract. 
  17. ↑ Johnston, Kristina L.; Bradford, Hannah; Hodges, Heather; Moore, Camille M.; Nauman, Emily; Olin, J. Tod (November 2018). "The Olin EILOBI Breathing Techniques: Description and Initial Case Series of Novel Respiratory Retraining Strategies for Athletes with Exercise-Induced Laryngeal Obstruction". Journal of Voice 32 (6): 698–704. doi:10.1016/j.jvoice.2017.08.020. PMID 29050661. 
  18. ↑ Heimdal, John-Helge; Maat, Robert; Nordang, Leif (May 2018). "Surgical Intervention for Exercise-Induced Laryngeal Obstruction". Immunology and Allergy Clinics of North America 38 (2): 317–324. doi:10.1016/j.iac.2018.01.005. PMID 29631739. 




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