Page 69 - Škrgat, Sabina, ed. 2022. Severe Asthma - Basic and Clinical Views. Koper: University of Primorska Press. Severe Asthma Forum, 1
P. 69
unctioning of the laryngeal muscles in 1842 been reported among individuals with ELO. 69
and was called “hysterical croup”15. Since The authors thought that sudden laryngeal
then, more than 70 different names have been closure could be triggered by poorer larynge- the char acteristics of upper respir atory tr act in the patients with asthma ...
used for the problem described. Recently, the al sensitivity or inflammation of the laryngeal
terms periodic occurrence of laryngeal ob- mucosa. Another possible explanation could
struction or episodic laryngeal obstruction be that the threshold of excitability is lowered,
(ELO) have been used, which include the pos- but when it is reached, it triggers a very strong
sibility of pathological events both at the lev- reaction in the sense of “all or nothing”13,22.
el of the vocal folds and at the level of the su- Some believe that the cause of mainly supra-
praglottis9. glottic approximation of structures is the neg-
ative inspiratory pressure during rapid deep
Etiology breathing which attracts tissues into the lu-
men of the larynx. They call it „bottle neck“
The etiology is not entirely clear. Among the theory based on special laryngeal anatomy
possible causes for inducible laryngeal ob- with narrow laryngeal inlet41,40. In the case
struction with breathing disorders many dif- of coexisting laryngopharyngeal reflux from
ferent factors and situations are mentioned: the oesophagus, the characteristic oedema of
the aerodynamic principles possibly con- the laryngeal inlet makes it even more pliable
nected with age, gender and physical capaci- and the approximation of aryepiglottic folds
ty ;20,45,29,40 alteration of the laryngeal sensibili- is more likely22.
ty after stimulation of the supraglottis mucosa
or direct stimulation of the superior larynge- Classification
al nerve by laryngopharyngeal reflux, aller-
gy, infections36,25,40, irritants, temperature and The ELO is divided into three categories ac-
humidity of the air in the surroundings26; and cording to the triggering factor:
psychological aspects42,23.
1. ELO due to irritation (substances from
Morrison hypothesized that the cause for the environment, laryngopharyngeal re-
abnormal laryngeal obstruction during inspi- flux),
ration is a change in the central nervous sys-
tem resulting in hyper-irritable state of the 2. exercise-induced laryngeal obstruction
sensory and motor pathways. Various patho- (EILO),
physiological processes lead to chronic ir-
ritation of the laryngeal nerves, and due to 3. psychogenic ELO.
the plasticity of the nervous system, the way
the central neurons respond to an incoming In fact, all three forms of ELO can be in-
stimulus may change. Thus, the event trig- tertwined. Airway obstruction can occur at
gers a sensory stimulus, and airway obstruc- the level of the vocal folds or supraglottis, or
tion occurs due to the hyperexcitable state of at both levels at the same time. In some pa-
the neural network in the brainstem that con- tients, vocal folds’ approach occurs not only
trols the functioning of the larynx32. Ayres during inspiration but also during expiration.
and Gabbott believe that the altered balance Between dyspnea attacks, the patient has no
of the autonomic nervous system maintained breathing problems9.
by structures in the central nervous system
plays a role in abnormal vocal folds move- Epidemiology
ment in patients with ELO5. Frequent prev-
alence of symptoms of laryngopharyngeal re- There are no accurate data on the prevalence
flux and decreased laryngeal sensitivity have of ELO in the population. ELO is thought
to be the real cause of breathing problems in
10% of patients who are unsuccessfully treat-
ed for asthma. It is often the cause of breathing
and was called “hysterical croup”15. Since The authors thought that sudden laryngeal
then, more than 70 different names have been closure could be triggered by poorer larynge- the char acteristics of upper respir atory tr act in the patients with asthma ...
used for the problem described. Recently, the al sensitivity or inflammation of the laryngeal
terms periodic occurrence of laryngeal ob- mucosa. Another possible explanation could
struction or episodic laryngeal obstruction be that the threshold of excitability is lowered,
(ELO) have been used, which include the pos- but when it is reached, it triggers a very strong
sibility of pathological events both at the lev- reaction in the sense of “all or nothing”13,22.
el of the vocal folds and at the level of the su- Some believe that the cause of mainly supra-
praglottis9. glottic approximation of structures is the neg-
ative inspiratory pressure during rapid deep
Etiology breathing which attracts tissues into the lu-
men of the larynx. They call it „bottle neck“
The etiology is not entirely clear. Among the theory based on special laryngeal anatomy
possible causes for inducible laryngeal ob- with narrow laryngeal inlet41,40. In the case
struction with breathing disorders many dif- of coexisting laryngopharyngeal reflux from
ferent factors and situations are mentioned: the oesophagus, the characteristic oedema of
the aerodynamic principles possibly con- the laryngeal inlet makes it even more pliable
nected with age, gender and physical capaci- and the approximation of aryepiglottic folds
ty ;20,45,29,40 alteration of the laryngeal sensibili- is more likely22.
ty after stimulation of the supraglottis mucosa
or direct stimulation of the superior larynge- Classification
al nerve by laryngopharyngeal reflux, aller-
gy, infections36,25,40, irritants, temperature and The ELO is divided into three categories ac-
humidity of the air in the surroundings26; and cording to the triggering factor:
psychological aspects42,23.
1. ELO due to irritation (substances from
Morrison hypothesized that the cause for the environment, laryngopharyngeal re-
abnormal laryngeal obstruction during inspi- flux),
ration is a change in the central nervous sys-
tem resulting in hyper-irritable state of the 2. exercise-induced laryngeal obstruction
sensory and motor pathways. Various patho- (EILO),
physiological processes lead to chronic ir-
ritation of the laryngeal nerves, and due to 3. psychogenic ELO.
the plasticity of the nervous system, the way
the central neurons respond to an incoming In fact, all three forms of ELO can be in-
stimulus may change. Thus, the event trig- tertwined. Airway obstruction can occur at
gers a sensory stimulus, and airway obstruc- the level of the vocal folds or supraglottis, or
tion occurs due to the hyperexcitable state of at both levels at the same time. In some pa-
the neural network in the brainstem that con- tients, vocal folds’ approach occurs not only
trols the functioning of the larynx32. Ayres during inspiration but also during expiration.
and Gabbott believe that the altered balance Between dyspnea attacks, the patient has no
of the autonomic nervous system maintained breathing problems9.
by structures in the central nervous system
plays a role in abnormal vocal folds move- Epidemiology
ment in patients with ELO5. Frequent prev-
alence of symptoms of laryngopharyngeal re- There are no accurate data on the prevalence
flux and decreased laryngeal sensitivity have of ELO in the population. ELO is thought
to be the real cause of breathing problems in
10% of patients who are unsuccessfully treat-
ed for asthma. It is often the cause of breathing
