What is Induced Laryngeal Obstruction (ILO) and how does it differ from Exercise Induced Laryngeal Obstruction (EILO)
Induced Laryngeal Obstruction (ILO) is characterized by trigger-induced laryngeal adduction that constricts the airway and causes dyspnea. ILO generally presents as inhalation difficulty and may include strider or wheezing. In addition to dyspnea, other symptoms of ILO may include a sensation of throat or chest tightness, cough, dysphonia, hyperventilation, and/or lightheadedness (Patel et al., 2015). Dyspnea is generally episodic, with sudden onset - often induced by an identifiable trigger such as physical exertion, stress, gastroesophageal reflux disease (GERD), scents, or exposure to an inhaled irritant (Sandage et al., 2022). Symptoms often resolve quickly upon exercise cessation or trigger removal.
ILO can be used as a general term for any type of induced laryngeal obstruction. Commonly used nomenclature, however, is generally based on symptom triggers. If dyspnea symptoms are triggered by physical exertion or exercise, the term Exercise Induced Laryngeal Obstruction (EILO) is used. The term ILO is used if symptoms are induced by non-physical exertion-related triggers (i.e., scents, irritants, stress, etc.). ILO can be used generally and refer to non-exertion-reduced symptoms specifically. This can be a little confusing, and it might help to think of ILO as a general condition with two subtypes: ILO (obstruction triggered by irritants, scents, or stress) and EILO (obstruction triggered by physical activity or exercise).
This ATE is an excerpt from the course, 20Q: Induced Laryngeal Obstruction - An Overview for Speech-Language Pathologists, presented by Robert Brinton Fujiki, PhD, CCC-SLP.