Introduction1
· Obstructive sleep apnea is defined as recurrent episodes of partial or complete upper airway obstruction during sleep resulting in repetitive apneas and/or hypopneas1.
· This is the most common type of sleep-disordered breathing, characterized by oxygen desaturations and arousals from sleep.
· If sleep-related obstruction in breathing is associated with excessive daytime sleepiness, it is termed as obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea-hypopnea syndrome (OSAHS).
Epidemiology2
· The prevalence of OSA varies according to the geographical location.
· It ranges from 9-37% in men and 4-50% in women2.
· Obstructive sleep apnea syndrome occurs in 6% of men and 4% of women2.
Risk factors
Male sex: Male to female ratio is 3:1.13. More among elderly males and postmenopausal women.
Obesity and increased neck circumference: Obesity is considered as a major risk factor for the development and progression of OSA3. Neck circumference of more than 17 inches in males and 15 inches in female increases the risk of OSA.
Craniofacial abnormalities such as micrognathia, retrognathia, and tonsillar hypertrophy are risk factors for OSA.
Risk factors in children5
Most cases of OSA in children are caused by either obesity or adenotonsillar hypertrophy.
Facial, oral, and throat asymmetry seen in numerous congenital syndromes like Pierre Robin anomaly and Treacher Collins syndrome leads to OSA.
Certain storage diseases, hypothyroidism, and Down syndrome result in upper airway crowding due to a relative increase in tongue mass causing OSA.
Neuromuscular diseases contribute to obstructive sleep apnea because of abnormal muscle tone in the pharyngeal constrictors.
Clinical features
Nocturnal symptoms of OSA include loud snoring, witnessed apneas, choking, nocturnal restlessness, nocturia and diaphoresis.
Daytime symptoms related with OSA are daytime hypersomnolence, non-restorative sleep, lack of concentration, cognitive deficits, mood changes, morning headache, dry mouth and decreased libido.
Symptoms in children include excessive daytime sleepiness, difficult arousing from sleep, aggressive behavior, poor school performance, attention deficit, hyperactivity, mouth breathing, nasal congestion and nasal speech.
Physical findings in OSA are obesity, increased neck circumference, large tongue, tonsillar hypertrophy, increased Mallampati score, craniofacial abnormalities such as micrognathia, features of hypothyroidism, systemic hypertension and pulmonary hypertension.
Classification
Obstructive sleep apnea is classified based on apnea-hypopnea index (AHI) measured by polysomnography.
If AHI is <5 it is normal, AHI of 5-15 is mild OSA, AHI of 15-30 is moderate OSA and AHI >30 is severe OSA.
Complications
Systemic inflammation in OSA results in many serious complications and comorbidities.
Major complications include systemic hypertension, Type-2 diabetes mellitus, metabolic syndrome, pulmonary hypertension, myocardial infarction, stroke and congestive cardiac failure.
Drivers with OSA are involved in motor vehicle accidents due to increased daytime sleepiness.
Work up4
Gold standard diagnostic test for OSA is polysomnography4. This is done either as a full night study or as a split night study.
Polysomnography assesses sleep stages, apnea, hypopnea, oxygen saturation, breathing effort, limb movements, heart rate and body positions.
Based on these apnea-hypopnea index (AHI) and respiratory disturbance index (RDI) are calculated.
Limited studies with portable monitors are used with less number of parameters to avoid hospitalization.
Management
Mild OSA is treated with lifestyle modification. This includes weight reduction, regular exercise, and sleep hygiene.
Moderate to severe OSA is treated with continuous positive airway pressure (CPAP) device.
Oral appliances for mandibular advancement is the option for mild to moderate OSA who do not tolerate CPAP or fails with CPAP
Surgical treatment such as correction of craniofacial abnormalities, uvulopalatopharyngoplasty are also considered for those who fail to respond to CPAP.
The accepted first-line treatment in children is tonsillectomy and adenoidectomy.
References
1. Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. The Report of an American Academy of Sleep Medicine Task Force. Sleep 1999; 22:667-89. [PubMed] [Google Scholar]
2. Franklin KA, Sahlin C, Stenlund H, et al. Sleep apnoea is a common occurrence in females. Eur Respir J 2013; 41:610-5. [PubMed] [Google Scholar]
3. Young T, Finn L, Peppard PE, et al. Sleep disordered breathing and mortality: eighteen-year follow-up of the Wisconsin sleep cohort. Sleep 2008; 31(8):1071–78.
4. Iber C, Ancoli-Israel S, Chesson AL, Quan SF. The AASM Manual for the Scoring of Sleep and Associated Events. Westchester,IL: American Academy of Sleep Medicine. 2007.
5. American Thoracic Society. Standards and indications for cardiopulmonary sleep studies in children. Am J Respir Crit Care Med 1996; 153:866–78.
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