Basics
Description
- Obstructive sleep apnea falls under the broad heading of sleep-disordered breathing, a spectrum of abnormal breathing patterns during sleep, including obstructive sleep apnea-hypopnea syndrome, central sleep apnea syndrome, Cheyne " Stokes respiration, and sleep hypoventilation syndrome.
- The obstructive sleep apnea-hypopnea syndrome (OSAHS) or obstructive sleep apnea syndrome (OSAS) consists of repetitive collapse of the upper airway during sleep, in conjunction with symptoms, including nonrefreshing sleep, daytime sleepiness, and sleep fragmentation.
- Definitions
- Obstructive apneas: Respiratory events associated with complete or near complete cessation of airflow and lasting at least 10 seconds
- Obstructive hypopneas: Respiratory events characterized by partial reductions in airflow and associated with oxygen desaturation >3% and/or EEG arousals from sleep
- Arousal: A shift in EEG frequency lasting at least 3 seconds " measure of sleep fragmentation
- Apneic hypopneic index (AHI): Number of episodes of apnea and hypopnea per hour of sleep
- Standard parameter used to report overall severity of OSA
- Rough but not consistent correlation with presence of symptoms
- Does not encompass other aspects of sleep apnea, such as arousals and oxygen desaturation
- Classification of severity based on AHI:
- Normal or 1 ° snoring AHI: <5 events/hour
- Mild OSA AHI: 5 " 15 events/hour
- Moderate OSA AHI: 15 " 30 events/hour
- Severe OSA AHI: >30 events/hour
Epidemiology
Marked increase in cases diagnosed each year due to increased recognition of the disorder and actual increase in prevalence due to increased obesity in population.
Incidence
- 108,000 cases diagnosed/year in 1990 in the US
- 1.3 million cases diagnosed/year in 1998
Prevalence
- Dependent on diagnostic criteria used
- Approximately 9% of women and 24% of men age 30 " 60 using AHI cutoff of ≥5 events/hour.
- Approximately 2% of women and 4% of men age 30 " 60 using AHI of ≥5 events/hour and daytime hypersomnolence (Wisconsin Sleep Cohort).
- More recent data suggests prevalence may be higher.
- Significantly increased in postmenopausal women and appears to be reduced with hormonal replacement therapy.
Risk Factors
- Male gender
- Overweight/obesity
- Wide neck circumference
- Increasing age
- Postmenopausal status
- Positive family history of OSA
- Craniofacial abnormalities
Genetics
Family and genetic studies suggest there is a genetic predisposition to OSA, but magnitude of genetic influence not well determined.
- Familial aggregation is common.
- Factors influencing genetic predisposition likely include:
- Obesity/fat distribution
- Presence of upper airway abnormalities
- Patterns of ventilatory control
Pathophysiology
- Narrowed upper airway susceptible to collapse during sleep when upper airway dilator muscle tone is reduced, despite compensatory increase in activity of these muscles.
- Occlusion of upper airway associated with ventilatory, hemodynamic, and metabolic effects.
- Obstructive apneas and hypopneas are associated with acute hypoxemia and hypercarbia, arousals from sleep, and reductions in intrathoracic pressure.
- Increased sympathetic nervous system activation and catecholamine release
- Increased heart rate and blood pressure
- Decreased stroke volume
- Insulin resistance and increased release of proinflammatory mediators
Etiology
- Overweight and obesity, especially central obesity
- Wide neck circumference major predictor
- Postmenopausal state
- Increasing age
Associated Conditions
Increased incidence in:
- Hypothyroidism
- Cushing 's syndrome
- Down 's syndrome
- Marfan 's syndrome
- Pierre Robin syndrome
- Polycystic ovarian syndrome
- Emerging as a manifestation of metabolic syndrome
- Any syndrome associated with macroglossia
Diagnosis
History
- Classic presentation is that of a patient with reported snoring and witnessed apnea accompanied by morning tiredness and excessive daytime sleepiness.
- Caution is needed when evaluating hypersomnolence, as some patients become habituated to chronic sleepiness and do not perceive themselves as being hypersomnolent, but have improved alertness and well-being following therapy of OSA.
- Some patients with severe OSA may truly not be hypersomnolent.
- Some patients may present with prominence of nocturnal symptoms such as sleep fragmentation and/or choking arousals.
- Depression or problems with memory and/or concentration may be part of the clinical presentation.
- Refractory hypertension, nocturnal angina pectoris, and new-onset atrial fibrillation are possible reasons for presentation.
- OSA may exacerbate migraine headaches, seizure disorders, and chronic pain syndromes.
- Signs and symptoms:
- Snoring
- Witnessed apnea
- Gasping or choking arousals
- Morning tiredness/nonrefreshing sleep
- Excessive daytime sleepiness
- Morning headaches
- Neurocognitive defects of attention, concentration, and/or memory
- Mood changes, irritability
- Sleep fragmentation
- Nocturia
- Enuresis
- Impotence/sexual dysfunction
Physical Exam
- Presence or absence of hypertension
- BMI: Overweight >25 kg/m2; obese >30 kg/m2
- Wide neck circumference
- ≥16 inches in women
- ≥17 inches in men
- Upper airway abnormalities
- Nasal obstruction: Septal deviation or nasal mucosal and turbinate edema
- Posterior pharyngeal narrowing
- Tonsillar hypertrophy/lateral narrowing from prominent tonsillar pillars
- Deep set palate/elongated, thick uvula
- Retrognathia/micrognathia
- Macroglossia
- Presence or absence of peripheral edema
Tests
Lab
Check TSH to screen for hypothyroidism
Surgery
All-night attended polysomnography (1)[A], which simultaneously monitors several physiologic signals including snoring, respiration, oxygen saturation, airflow via nasal and oral sensors, sleep stage distribution via EEG, and cardiac rate and rhythm, is the gold standard for diagnosis. Sensitivity and specificity of home studies are significantly lower, but portable testing is an alternative if clinical suspicion is high.
Differential Diagnosis
Differential diagnosis of excessive daytime sleepiness:
- Insufficient sleep
- Sleep fragmenting process other than OSAS, such as Periodic Limb Movement Disorder
- Disorder of sleep drive such as narcolepsy
- Circadian rhythm disorder such as Shift Work Sleep Disorder
- Sedating medication or drug effect
- Depression may present with excessive daytime sleepiness.
Treatment
Medication
Modafinil: Can be used as adjunctive therapy in patients with residual symptoms after primary treatment of the OSA
- Minimal risk of cardiovascular side effects
- Not found to be habit forming
- Common side effect is headache, more likely to occur in patients with preexisting headaches.
- Potential for reduced steroidal contraceptive action, including depot and implantable agents; avoid use of this drug in patients on steroidal contraceptives.
- Use with caution in patients with Bipolar Affective Disorder or other psychiatric illness
- Pregnancy category C
Additional Treatment
General Measures
- Weight loss beneficial; often not curative (2)[B]
- Positional management: Patient conditions self to sleeping in lateral decubitus position
- Treatment of nasal congestion
- Consider repair of deviated nasal septum
- Avoidance of evening alcohol consumption
- Avoidance of sedating medications, especially benzodiazepines
- Screening for hypothyroidism
- For patients with OSAS who are hospitalized:
- Continue CPAP (continuous positive airway pressure) or BIPAP (bilevel positive airway pressure) therapy during their hospitalization
- Minimize sedative hypnotics and narcotics
Additional Therapies
- Positive airway pressure (PAP) is most effective treatment modality available and is considered first-line therapy for moderate-to-severe OSAS (3)[A].
- Oral appliances and upper airway surgery are other potential therapies.
- PAP therapy: Positive pressure is applied to the upper airway via a nasal or oronasal interface, thereby maintaining airway patency.
- Compliance with PAP therapy shown to be higher in moderate-to-severe disease; patients with mild disease whose symptoms warrant can benefit from PAP therapy (3)[C].
- In patients that cannot be controlled with CPAP, BIPAP may be effective.
- Treatment with CPAP has a multitude of beneficial effects including improvement in daytime sleepiness and well-being, neurocognitive deficits and mood, hypertension, and cardiovascular risk reduction.
- Therapy with oral appliance
- Consider in patients with:
- Mild-to-moderate OSA (4)[B]
- Patients intolerant of CPAP
- Patients with retrognathia
- Patients without markedly narrowed posterior pharynx
- Need to have fair-to-good dentition
- For treatment of OSA, as opposed to primary snoring only, an adjustable oral appliance is needed, fitted by a qualified orthodontist. A "one-size-fits-all " snoreguard can be effective for snoring alone.
- Surgical therapy (5)[C]
- Uvulopalatopharyngoplasty (UPPP): Success rate 40 " 50%
- Laser-assisted uvuloplasty (LAUP) only effective for snoring, not OSAS
- Radiofrequency ablation at palate level or retrolingual (RFA, somnoplasty)
- More advanced maxillomandibular surgery
- Genioglossal advancement, genioglossal advancement with hyoid myotomy, or maxillomandibular osteotomy and advancement
- Surgery often performed in staged fashion with UPPP first, followed by re-evaluation of OSA, and then additional jaw advancement procedure if warranted.
- Tracheostomy: Therapy of last resort for patients with severe OSAS who cannot tolerate CPAP or BIPAP or in whom such therapy is ineffective.
- Bariatric surgery: Significant improvement and sometimes cure reported, considered an option for high-risk patients (2)[C].
Ongoing Care
Complications
- Cardiovascular
- Hypertension: Significant independent risk even when controlling for obesity, smoking, diabetes mellitus
- Coronary artery disease: Increased prevalence of OSA in patients with myocardial infarction and angina pectoris
- Congestive heart failure: In Sleep Heart Health Study, odds ratio was 4.37 for patients in highest quartile of OSAS severity
- Arrhythmias
- Bradycardias and episodes of asystole
- Ventricular arrhythmias
- Increased prevalence of atrial fibrillation
- Stroke: High prevalence of OSA; causative role not definitively proven
- Pulmonary hypertension
- More likely in patients with daytime hypoxemia
- OSAS alone does not generally cause severe pulmonary hypertension.
- Patients with coexistent obstructive lung disease, the Overlap Syndrome, can develop pulmonary hypertension with less severe degrees of OSA.
- Hypercapnia: Vast majority of patients with OSAS do not have daytime hypercapnia; its presence suggests associated obesity hypoventilation or hypoventilation of other causes.
- Sleepiness while driving and increased risk of motor vehicle accidents (MVA)
- Risk of MVA increased as much as 7-fold
- Higher risk in patients with near misses
- Physician responsibility to counsel patients on risks of driving while sleepy
References
1Kushida CA, Littner MR, Morgenthaler T. Practice parameters for the indications for polysomnography and related procedures: An update for 2005. Sleep. 2005;28(4):499 " 521. [View Abstract]2Morgenthaler TI, Kapen S, Lee-Chiong T. Practice parameters for the medical therapy of obstructive sleep apnea. Sleep. 2006;29(8):1031 " 1035. [View Abstract]3Kushida CA, Littner MR, Hirshkowitz M. Practice parameters for the use of continuous and bilevel positive airway pressure devices to treat adult patients with sleep-related breathing disorders. Sleep. 2006;29(3):375 " 380. [View Abstract]4Kushida CA, Morgenthaler TI, Littner MR. Practice parameters for the treatment of snoring and OSA with oral appliances: An update for 2005. Sleep. 2006;29(2):240 " 243. [View Abstract]5Aurora RN, Casey KR, Kristo D. Practice parameters for the surgical modifications of the upper airway for obstructive sleep apnea in adults. Sleep. 2010;33(10):1408 " 1413. [View Abstract]
Additional Reading
1Epstein LJ, Kristo D, Strollo PJ. Clinical guideline for the evaluation, management, and long-term care of OSA in adults. J Clin Sleep Med. 2009;5(3):263 " 276. [View Abstract]
Codes
ICD9
780.53 Obstructive sleep apnea
ICD10
G47.33 Obstructive sleep apnea (adult) (pediatric)
SNOMED
78275009 obstructive sleep apnea syndrome (disorder)
Clinical Pearls
- Common sleep disorder, more prevalent in men but common in women as well
- Associated with nocturnal and daytime symptoms including daytime hypersomnolence, neurocognitive deficits, and mood changes
- High index of suspicion
- In patients who are overweight or obese
- In postmenopausal women
- In patients with craniofacial abnormalities
- Consider in anyone with suggestive symptoms and reported snoring