Turbulent airflow and subsequent progressive vibratory trauma to the soft tissues of the upper airway are important factors that contribute to the condition.
Anatomic obstruction leads to increased negative inspiratory pressure, which propagates further airway collapse, turbulence, and noise.
The imbalance between the forces that act to maintain airway patency (the force of the pharyngeal muscles) and the negative inspiratory forces generated by the diaphragm is thought to be the primary etiology of anatomic obstruction in OSA.
In OSA, the tongue contacts the soft palate and posterior pharyngeal wall in the presence of lateral collapse of the pharynx, generating occlusion.
Significant factors that contribute to this condition include
- obesity
- redundant tissue in the neck
- retrognathia
- craniofacial anomalies
- anatomic abnormalities of the nasal airway (eg, septal deviation, inferior turbinate hypertrophy, nasal-valve narrowing, adenoid hypertrophy)
- Alcohol and other sedatives may increase the severity of OSA.
- Data from a recent meta-analysis by Rada also suggested a causal relationship between OSA and head and neck cancer (which may first manifest as OSA).
In children :
OSA in children is usually due to large tonsils and adenoids. There is no relation, however, between tonsils and adenoid size and the degree of OSA. This is probably due to the combined effects of muscle tone, pharyngeal size and adenotonsillar hypertrophy.
High risk groups include children with craniofacial anomalies, cerebral palsy, muscular dystrophy and Down syndrome.
Children with OSA are not usually obese, but OSA does occur frequently in morbidly obese children and adolescents.
Source : The American Sleep Apnea Association (ASAA)
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