What condition is most likely to be responsible for his sleepiness?A 55-year-old white male presents to your office after an accident. He reports rear-ending another vehicle with his truck. He complains of some neck soreness, but no other injuries. Later he admits to having fallen asleep at the wheel right before the accident occurred. He has gotten sleepy while driving in the past, and even dozed off for a second, but never had an accident. He sleeps 7 to 8 hours per night but doesn’t feel rested in the morning. His wife reports that he is a loud snorer. On examination, he is an overweight-appearing man with a short, wide neck. His body mass index (BMI) is 36 kg/m2, BP is 147/96, pulse 88 beats/min, and respiratory rate 16 breaths/min. On HEENT examination, you can only see his hard palate when he opens his mouth and says “ahhh.” Heart and lung examinations are unremarkable. On examination of his neck, he has mild paraspinal muscle tenderness, but no midline cervical tenderness and he has full range of motion.
What condition is most likely to be responsible for his sleepiness?
What should be the next step in the evaluation?
What would be the most effective initial management?
Summary: A 55-year-old man with excessive daytime sleepiness resulting in a motor vehicle accident presents to the office. On examination, he is an obese male with a short, wide neck and his blood pressure is in the hypertensive range.
• Condition responsible for his sleepiness: Obstructive sleep apnea
• Next step in his evaluation: Comprehensive sleep evaluation including Epworth Sleepiness Scale and polysomnogram
• Most effective initial therapy: Continuous positive airway pressure (CPAP) for night time use and lifestyle modifications including weight reduction
1. Identify who is at risk for obstructive sleep apnea, the signs and symptoms of obstructive sleep apnea, and indications for conducting a comprehensive sleep evaluation.
2. Understand the pathophysiology and differential diagnosis of obstructive sleep apnea.
3. Understand the diagnosis and management of obstructive sleep apnea and the importance of patient support and education.
4. Identify comorbid conditions associated with obstructive sleep apnea.
The patient in this case presents with a history and examination that suggests a diagnosis of obstructive sleep apnea. The first step in his management is advising him not to drive, for the safety of himself and others, until further evaluation and treatment has taken place. A comprehensive sleep evaluation, including a sleep history, medical history, and physical examination, should be performed. Confirmation of the diagnosis of obstructive sleep apnea is then obtained by overnight polysomnography. The initial treatment approach should include patient education and continuous positive airway pressure with close follow-up.
APNEA: Defined in adults as breathing pauses lasting at least 10 seconds accompanied by a 90% or more drop in airflow
HYPOPNEA: A 50% reduction in airflow lasting at least 10 seconds with a 3% drop in oxygen saturation, or a 30% reduction in airflow lasting at least 10 seconds with a 4% drop in oxygen saturation
APNEA HYPOPNEA INDEX (AHI): Number of apneas and hypopneas per hour of sleep
RESPIRATORY DISTURBANCE INDEX (RDI): Number of apneas, hypopneas, and respiratory effort–related arousals (RERAs) per hour of sleep
RERA: Respiratory effort–related arousals
Obstructive sleep apnea (OSA) is a chronic disease that affects 2% to 9% of adults and 2% to 5% of children. It causes significant morbidity including excessive daytime sleepiness (EDS), cognitive impairment, increased risk of motor vehicle accidents, and impaired relationships. It has been associated with several metabolic and cardiovascular conditions (Table 57–1).
Table 57–1 • CONDITIONS ASSOCIATED WITH OSA
People with OSA experience repetitive collapse of the upper airway during sleep leading to hypopneas, apneas, and RERAs. The upper airway is comprised of flexible muscles that allow for the processes of speech, respiration, and eating. They lack rigid support and during normal sleep this muscle tone decreases. In OSA, collapse of the flexible musculature of the upper airway during sleep leads to reduced or absent airflow despite continued respiratory effort. This is demonstrated on the polysomno-gram (PSG) by abdominal and chest wall movement during an obstructive event. In contrast, during a central apnea there is no respiratory effort, evidenced by absence of chest wall or abdominal wall movement on PSG. The collapse of the upper airway musculature results in occlusion and apnea (often preceded by snoring), which leads to hypoxia and hypercapnia. This results in arousal, wakefulness, and increased sympathetic activity in an attempt to restore airway patency, leading to fragmented sleep. Pathophysiologic factors associated with OSA are listed in Table 57–2.
Table 57–2 • PATHOPHYSIOLOGIC FACTORS ASSOCIATED WITH OSA
Diagnosis of obstructive sleep apnea is based on a comprehensive sleep evaluation, which includes a sleep-related history and physical examination. If OSA is suggested by the history and physical, a polysomnogram must be performed to confirm the diagnosis and to determine the severity of OSA, which will help guide treatment. A differential diagnosis for OSA is included in Table 57–3.
Table 57–3 • DIFFERENTIAL DIAGNOSIS FOR OSA
A comprehensive sleep history includes asking about snoring, daytime sleepiness not explained by other causes, witnessed apneas, choking or gasping during sleep, sleep amount, nocturia, decreased libido, morning headache, insomnia, frequent awakenings, concentration and memory, alertness, and history of falling asleep at the wheel. Often a patient’s partner will be able to provide important information. It is important to ask about other medical conditions that could be related to OSA.
Several standardized scales are available to assess fatigue and sleepiness. The most widely used, the Epworth Sleepiness Scale, is a useful tool to help determine the extent of sleepiness, although a low score does not rule out sleep apnea. Other available tools include the Stanford Sleepiness Scale and the Fatigue Severity Scale.
The physical examination should include evaluation for features suggestive of the presence of OSA. They include BMI over 30 kg/m2, hypertension, retrognathia, obesity, thick neck, macroglossia (large tongue), acromegaly, thyroid enlargement, large tonsils, enlarged uvula, enlarged nasal turbinates or polyps, and narrow or high-arched palate. The appearance of the oropharynx may be assessed using the Mallampati Score (Table 57–4).
According to the American Academy of Sleep Medicine (AASM), in-lab (PSG) and home testing with portable monitors are acceptable objective tests for OSA. PSG includes the following physiologic assessments: EEG, ECG or heart rate, electrooculogram (EOG), chin electromyogram (EMG), airflow, and oxygen saturation. Additionally, anterior tibialis EMG can help assess for periodic limb movements which can coexist with sleep-related breathing disorders.
According to AASM, the diagnosis of OSA in adults is confirmed by: AHI or RDI ≥15, defined by at least 15 obstructive events (apneas, hypopneas, RERAs) per hour on polysomnogram with or without symptoms
Or
AHI or RDI ≥5, defined by 5 or more obstructive respiratory events per hour on polysomnogram in a patient who has symptoms of: daytime sleepiness, unrefreshing sleep, fatigue, insomnia, nighttime awakenings associated with gasping, choking, or breath holding, or witnessed loud snoring and/or breathing interruptions
Severe OSA is defined as having more than 30 RDI per hour; moderate OSA is defined as 15 and 30 RDI per hour and mild OSA is defined as 5 to 15 RDI per hour.
There are medical, behavioral, and surgical therapies for OSA and treatment should involve a multidisciplinary approach. It is important to include the patient in the decision-making process when deciding on treatment options. Positive airway pressure (PAP) is the treatment of choice for OSA of all severities, although alternative therapies may be indicated based on the patient’s anatomy and severity of OSA.
All patients should be educated on behavioral changes. These include weight loss, avoidance of alcohol and sedating medications, modifying risk factors, and driving precautions. Some individuals have elevated AHI or RDI in the supine, but not in other positions and may benefit from sleep-position measures to prevent sleeping in the supine position. One technique would be sewing a tennis ball to the back of the pajamas to prevent supine sleeping. After significant weight loss, the need for continued therapy or for PAP adjustment should be evaluated.
Positive airway pressure acts as support to maintain patency of the upper airway and reduces the AHI. The level of PAP is determined by an in-lab attended overnight PSG and sometimes by a split-night diagnostic and titration study. A split night study may occur if a patient has AHI ≥40 during 2 hours of a diagnostic study; in this case, PAP may be applied and titrated in the same night.
Different modes of PAP delivery include continuous (CPAP), bilevel (BiPAP), and automatic titrating (APAP). PAP can be applied using a full face mask, oral mask, nasal mask, or nasal pillows. Heated humidification can assist in patient comfort. Adverse effects include nasal congestion and dryness, nosebleeds claustrophobia, inconvenience, air swallowing, skin rash, or minor trauma from the mask. Close follow-up with the health-care team is imperative, especially within the first few weeks after initiation.
Oral appliances work by enlarging the upper airway and preventing upper airway collapse. Examples include mandibular repositioning appliances (MRA) and tongue retaining devices (TRD). They are not as effective as PAP, but are indicated for people with mild to moderate OSA who have contraindications to the use of PAP, cannot tolerate PAP, or in whom PAP and behavioral therapy is ineffective. Patients should have a thorough dental examination prior to consideration of use. A repeat sleep study should be performed with the oral appliance in place in order to assess the treatment outcome. Regular follow-up with a dental specialist trained in sleep medicine should occur.
Surgical therapy may be considered as primary therapy if the OSA is mild and there is an anatomical cause of major airway obstruction that can be reversed. Surgery can be considered as secondary therapy after a trial of PAP or an oral appliance if treatment response is inadequate, or if the patient does not tolerate them. Surgery may also be used as an adjunct to other therapies. Bariatric surgery may be a helpful adjunct to other OSA treatments in patients who have failed to lose weight through lifestyle modifications. Tracheostomy is curative and can be considered in extremely advanced treatment refractory cases. There is no pharmacologic therapy for OSA aside from treating underlying diseases such as acromegaly or hypothyroidism.
All patients with OSA need individualized care and regular follow-up to assess symptoms, treatment response, side effects, and medical conditions associated with OSA.
57.1 A 47-year-old obese female presents to your office complaining of excessive daytime sleepiness, snoring, and frequent awakenings from sleep. She is having difficulty concentrating and her sleepiness is affecting personal and professional relationships. As you perform your comprehensive sleep history and physical examination, you determine she is at risk for OSA. Which of the following physical examination findings is most suggestive of OSA?
A. Mallampati score of 2
B. Obesity
C. Acanthosis nigricans
D. 2+ pitting peripheral edema
E. Elevated blood pressure
57.2 You decide to perform an overnight PSG to confirm the diagnosis for the patient in question 57.1. The study is converted into a split night study because her AHI was found to be over 40 in the first 2 hours of the study. What is the diagnosis?
A. Mild obstructive sleep apnea
B. Moderate obstructive sleep apnea
C. Severe obstructive sleep apnea
D. Positional obstructive sleep apnea
E. Central apnea
57.3 What is the next step in management of the patient in question 57.2?
A. In-lab attended overnight polysomnography for PAP titration
B. Treatment with PAP
C. Surgical referral
D. Pulmonary function testing
E. Dental evaluation for oral appliance
57.4 A 54-year-old man comes to your clinic for OSA follow-up. He has been using PAP with a nasal mask for the last 3 years since he was diagnosed. He has a recently purchased CPAP machine and tells you he has been unable to use it because of discomfort. You check the machine and all parts are in good condition. What is the best next step?
A. Decrease the pressure.
B. Refer to surgery.
C. Refer for an oral appliance.
D. Change the mask.
E. Add heated humidification.
57.1 B. Obesity is the physical examination finding most suggestive of the presence of OSA. People who are obese are considered to be at high risk for OSA. A Mallampati score of 3 or more suggests increased risk for OSA. Acanthosis nig-ricans is suggestive of insulin resistance. Peripheral edema has a broad differential diagnosis and further evaluation is warranted. Elevated blood pressure, in contrast to resistant hypertension, is not a risk factor for OSA.
57.2 C. This patient has severe OSA based on a respiratory disturbance index (RDI) over 30 per hour.
57.3 B. Positive airway pressure is the treatment of choice for OSA and, as this patient had an AHI over 40 for 2 hours of the study, it was converted into a split night study, meaning PAP was applied and titrated in the same night. Surgery and oral appliances are alternative treatment options, but for this patient the initial treatment should be PAP. Pulmonary function testing is not indicated.
57.4 E. Heated humidification is indicated to improve patient comfort while using PAP. If the patient remains uncomfortable despite this addition, other measures should be taken such as a trial of a different type of mask (eg, nasal pillows), or pressure relief. If all modifications and patient comfort interventions fail, then an alternative treatment may be necessary.
OSA is a chronic treatable disease that, if left untreated, is associated with increased risk of several cardiovascular disorders.
A diagnosis of OSA should be considered in people with high-risk medical conditions, or features on history or physical examination that may suggest the presence of this disease.
Polysomnography is required to confirm the diagnosis of OSA and determine the severity, which will help to guide treatment.
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