PANCE Blueprint Pulmonary (10%)

Sleep Apnea and Obesity Hypoventilation Syndrome

Patient will present as →  a 48-year-old man is brought to his physician by his wife, who is concerned about his daytime sleepiness. Last week, he 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 37 C (98.6 F), heart rate is 86/min, blood pressure is 156/95 mm Hg, respiratory rate is 12/min. On physical exam, he is obese, but chest auscultation and extremity exam are 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

Polysomnography (overnight sleep study in a sleep laboratory) confirms the diagnosis 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.

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 air flow
  • Tracheostomy is a last resort for those in whom all other therapies have failed or who have life-threatening OSA (severe hypoxemia or arrhythmias)

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-side 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.

Obstructive Sleep Apnea Picmonic

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?
A
narcolepsy
B
obstructive sleep apnea (OSA) syndrome
C
generalized poor physical condition
D
central sleep apnea syndrome
E
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?
A
collapse of the pharyngeal walls repetitively during sleep
B
failure of upper airway dilator muscle activity
C
sleep-related upper airway obstruction and cessation in ventilation (apneas)
D
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?
A
hypoxemia
B
hypercarbia
C
metabolic acidosis
D
respiratory acidosis
E
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?
A
systemic hypertension
B
inhibited sexual desire
C
depression
D
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?
A
alcohol intake
B
benzodiazepines
C
hyperthyroidism
D
a and b
E
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?
A
uvulopalatopharyngoplasty surgery (UPP)
B
tracheostomy
C
continuous positive airway pressure (CPAP)
D
nortriptyline
E
alprazolam
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.
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