Obstructive Sleep Apnea
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Introduction
Intermittent partial or complete occlusion of upper airway during sleep.
It leads to profound disturnances in homeostatic gas exchange.
Snoring is very highly prevalent, affecting 27% of children. OSAS affects 2-3% of children.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
Obesity has a significant 20-40% of obese adults
Risk factors include:
- male gender
- obesity
- alcohol, sedatives, or muscle relaxants
- smoking
- decreased muscle tone
- persistent URTIs, allergies, nasal tumours, hypothyroidism
- family history
Children
- adenotonsillar hypyertrophy
- obesity
Pathophysiology
Snoring results from soft tissue vibration at the back of the nose and throat due to tubulent airflow through narrowed air passages.
Obstructive sleep apnea (OSA) results from upper airway obstruction due to collapse of the base of the tongue, soft palate with uvula, and epiglottis. Breathing efforts are therefore prevented, from 20 sec up to 3 min.
A distinctive snorting, choking results as the body arouses itself to take a resuscitive breath. This cycle can occur 100-600 times nightly.
Central sleep apnea is the failure of the brain to send signals to muscles of repiration, resulting in absence of respiratory efforts. It is often secondary to CNS diseases such as brainstem infarction, infection, neuromusclular disease.
Elevations in upper airway resistancy as pharngeal muscle tone decreases.
Obesity leads to fatty deposition, remodeling the aiwray. For every BMI increase of 1, the likelihood of OSA increases by 1%.
In children, adenotonisillar hypertrophy further contributes and can lead to airway collapse. Hypertrophy, however, does not always lead to OSA in children.
EEG changes show cortical activity and arousal during periods of OSA.
Heart rate also increases during periods of apnea.
Signs and Symptoms
- history
- physical exam
History
Symptoms in children are less specific than adults
Physical Exam
A physical exam includes assessing obesity and looking for nasal polyps, septal deviation, turbinate hypertrophy, and enlargement of the uvula and tonsils.
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Nocturnal polysomnography will diagnose OSA if more than 15 apneic episodes, with arousal, are recorded.
Differential Diagnosis
Treatments
Treatment for snoring includes:
- weight loss
- sleep on side
- avoiding alcohol, sedatives, narcotics
- nasal steroids can help with swelling
- nasal dilators, tongue retaining devices, mandibular advancement dental devices
Primary treatment for OSA is CPAP (continuous positive airway pressure); this will maintain a patent airway in 95% of cases
Surgery: sonmoplasty, tonsillectomy, adenoidectomy, uvulopalatopharyngoplasty
If OSA is not controlled by CPAP, report to Ministry of Transportation.
In children, adenotonsillectomy results in 82% improvement rate.
Consequences and Course
Sleep apnea very often markedly decreased quality of life. It can cause:
- daytime somnolence due to nonrestorative sleep
- poor social and work performance
- mood changes: anxiety, depression, irritability
- sexual dysfunction: poor libido, impotence
- morning headache (hypercapnia)
- hypertension, CAD, stroke, arrhythmias
- pulmnoary hypertension, RV dysfunction, cor pulmonale
- memory loss, decreased concentration, confusion
OSA is also an independent cardiac risk factor.
- tachcardia from increased catecholamines
- increased peripheral vascular resistance
- endothelial dysfunction - reversible with CPAP
- oxidative stress
- inflammation
- early plaque formation
Topic Development
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