PANCE Blueprint Pulmonary (10%)

Sleep Apnea and Obesity Hypoventilation Syndrome

Patient will present as →  a 49-year-old man who is brought to your office by his partner, who is concerned about his daytime sleepiness. Last week, the patient fell asleep while stopped at a red light. She says that he snores loudly and sometimes stops breathing for a few seconds while sleeping. His past medical history is significant for hypertension. He has a 20-pack-year history of smoking. His temperature is 98.6 F, heart rate is 86/min, blood pressure is 148/98 mm Hg, respiratory rate is 12/min. On physical exam, he is obese. His lungs are clear and his lower extremity exam is within normal limits.

What test establishes the diagnosis of OSA?
Nocturnal PSG, or sleep study

Intermittent obstruction of the airflow (typically at the level of the oropharynx) produces periods of apnea during sleep

  • Each apneic period is usually 20 to 30 seconds long (but may be longer) and results in hypoxia, which arouses the patient from sleep. This occurs multiple (sometimes hundreds of) times overnight.

Risk factors

  • Obesity (especially around the neck): nonobese patients can also have OSA
  • Structural abnormalities: enlarged tonsils, uvula, soft palate; nasal polyps; hypertrophy of muscles in the pharynx; deviated septum; deep overbite with a small chin
  • Family history
  • Alcohol and sedatives worsen the condition
  • Hypothyroidism (multifactorial)

Presents as:

  • Snoring and daytime sleepiness due to disrupted nocturnal sleep
  • Personality changes, decreased intellectual function, decreased libido, morning headaches, polycythemia
  • Repeated oxygen desaturation and hypoxemia can lead to systemic and pulmonary HTN as well as cardiac arrhythmias

Obesity-hypoventilation syndrome (OHS) (historically described as the Pickwickian syndrome)

  • Consists of the triad of obesity (BMI > 30), sleep-disordered breathing, and chronic hypercapnia (PCO2 > 45 mmHG) during wakefulness in the absence of other known causes of hypercapnia
  • Signs and symptoms of obesity hypoventilation syndrome (OHS) are essentially the same as OSA. These two diseases are often concurrent.

Polysomnography (overnight sleep study in a sleep laboratory) confirms the diagnosis of obstructive sleep apnea and can distinguish OSA from CSA

  • Home sleep apnea testing (HSAT) may be an acceptable alternative for patients who are strongly suspected of having OSA and who do not have medical comorbidities (eg, heart failure or lung disease)

In adults, a diagnosis of OSA is defined by either of the following:

Five or more predominantly obstructive respiratory events per hour of sleep (for polysomnography) or recording time (for HSAT) in a patient with one or more of the following:

  • Sleepiness, nonrestorative sleep, fatigue, or insomnia symptoms
  • Waking up with breath-holding, gasping, or choking
  • Habitual snoring, breathing interruptions, or both noted by a bed partner or other observer
  • Hypertension, mood disorder, cognitive dysfunction, coronary artery disease, stroke, congestive heart failure, atrial fibrillation, or type 2 diabetes mellitus

Fifteen or more predominantly obstructive respiratory events per hour of sleep (for polysomnography) or recording time (for OCST), regardless of the presence of associated symptoms or comorbidities

Obesity-hypoventilation syndrome (OHS) is a diagnosis of exclusion that can be made when the following criteria are met:

  • Obesity (body mass index [BMI] >30 kg/m2)
  • Awake alveolar hypoventilation as indicated by a partial arterial pressure of carbon dioxide >45 mmHg
  • Alternative causes hypercapnia and hypoventilation have been excluded

Management of obstructive sleep apnea

Behavior modification: which includes weight loss and exercise, avoiding alcohol and sedatives, and sleeping in a nonsupine position

Mild to moderate OSA: 

  • Positive airway pressure therapy
  • If the patient refuses or there are issues with compliance, an oral appliance can be offered

Severe OSA:

  • Continuous positive airway pressure (CPAP) provides positive pressure, thus preventing occlusion of the upper pharynx. This is the preferred therapy for the majority of patients because it is noninvasive and has proven efficacy. It is poorly tolerated by some due to noise and discomfort
  • Uvulopalatopharyngoplasty—removal of redundant tissue in oropharynx to allow more airflow
  • Tracheostomy is a last resort for those in whom all other therapies have failed or who have life-threatening OSA (severe hypoxemia or arrhythmias)

Management of obesity hypoventilation syndrome

  • Weight loss +/- CPAP at night
  • For patients with OHS who fail or do not tolerate first-line therapies in whom aggressive attempts have been made to optimize PAP therapy, options include tracheostomy for the treatment of sleep-disordered breathing and bariatric surgery or rarely medication for weight loss

osmosis Osmosis
Obstructive Sleep Apnea Osmosis

Obstructive sleep apnea (OSA) is caused by narrowing or obstruction of the airway during sleep. A patient diagnosed with this disorder will experience five or more episodes of apnea per hour. When a patient becomes hypercapnic due to periods of apnea, they will experience a startle response, in the form of a snort or a gasp, which allows the tongue and soft palate to fall forward, thereby reopening the patient’s airway. Loud, frequent snoring, daytime sleepiness, and headaches are also common clinical manifestations in those with OSA. Complications of untreated sleep apnea include hypertension, right-sided heart failure from pulmonary hypertension, and cardiac dysrhythmias. Interventions to treat obstructive sleep apnea include changing the patient’s sleeping position, use of an oral appliance such as a mouth guard, CPAP, BiPAP, or surgical interventions. Patients with OSA should be encouraged to lose weight, as being overweight or obese worsens sleep apnea.

Play Video + Quiz

Question 1
A 48-year-old man comes to your office with his wife. His wife tells you that “he is constantly snoring” and she has put up with all she can. This has been going on for a number of years, but it has been getting worse lately. His wife also tells you that “sometimes he even stops breathing during the night.” When you ask the patient directly, he says, “Well, I may snore a bit, but I think my wife is exaggerating.” You somehow doubt this statement. There is a history of sleepiness during the day; he has fallen asleep at his desk at work. On examination, the patient weighs 310 pounds. His blood pressure is 200/105   mm Hg (measured with a large cuff). Head, ears, eyes, nose, and throat examination shows boggy nasal mucosa but a normal pharynx. A grade 3/6 systolic murmur is present along the left sternal edge. You believe that there is elevated jugular venous pressure when he lies at a 45-degree angle. Chest is normal to auscultation and percussion. His abdomen is obese, and his extremities are without edema. What is the most likely diagnosis in this patient?
obstructive sleep apnea (OSA) syndrome
generalized poor physical condition
central sleep apnea syndrome
adult-onset adenoid hypertrophy
Question 1 Explanation: 
This patient has OSA. Polysomnography will confirm the diagnosis and will demonstrate disordered sleep with periods of apnea and hypopnea.
Question 2
To what is the pathophysiology of obstructive sleep apnea related?
collapse of the pharyngeal walls repetitively during sleep
failure of upper airway dilator muscle activity
sleep-related upper airway obstruction and cessation in ventilation (apneas)
a, b, and c
Question 2 Explanation: 
The pathophysiology of OSA syndrome includes the following: (1) the pharyngeal walls collapse repetitively during sleep, causing intermittent sleep-related upper airway obstruction and cessation in ventilation (apneas); (2) the cessation of ventilation is related to a concomitant loss of inspiratory effort; and (3) upper airway closure in OSA results from a failure of the genioglossus and other upper airway dilator muscles, and apnea results.
Question 3
Obstructive sleep apnea is accompanied by which of the following?
metabolic acidosis
respiratory acidosis
a, b, and d
Question 3 Explanation: 
OSA produces the following acid-base balance situation: (1) apnea causes hypercarbia, hypoxemia, and a resulting respiratory acidosis; and (2) only if there is another preexisting condition associated with OSA will metabolic acidosis be produced.
Question 4
What is (are) the clinical feature(s) associated with the condition described?
systemic hypertension
inhibited sexual desire
all of the above
Question 4 Explanation: 
Associated clinical features of OSA include systemic hypertension; inhibited sexual desire; impotence; ejaculatory impairment; depression; deficits in attention, motor efficiency, and graphomotor ability; deterioration in interpersonal relationships; marital discord; and occupational impairment.
Question 5
What is (are) the factor(s) predisposing to this condition?
alcohol intake
a and b
all of the above
Question 5 Explanation: 
Factors that predispose to OSA include sedating pharmacologic agents such as alcohol and benzodiazepines (all are contraindicated in OSA); nasal obstruction; large uvula; low-lying soft palate; retrognathia, micrognathia, and other craniofacial abnormalities; pharyngeal masses such as tumors or cysts; macroglossia; tonsillar hypertrophy; vocal cord paralysis; obesity; hypothyroidism; and acromegaly.
Question 6
What is the treatment of first choice for this disorder?
uvulopalatopharyngoplasty surgery (UPP)
continuous positive airway pressure (CPAP)
Question 6 Explanation: 
The most established management options, in addition to weight loss, in order of preference are as follows: (1) CPAP, (2) UPP, and (3) tracheostomy. Additional measures are antidepressants that are stimulating, such as protriptyline, fluoxetine, sertraline, and paroxetine, particularly with coexistent depression. Chronic anxiety, which may complicate the OSA picture, should not be managed with benzodiazepines. Instead, the nonbenzodiazepine buspirone, which does not appear to aggravate OSA, should be used, along with behavioral treatments. Thus, alprazolam is contraindicated.
There are 6 questions to complete.
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References: Merck Manual · UpToDate

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