Review Question - QID 106572

This clinical presentation is consistent with obstructive sleep apnea (OSA), the most common cause of daytime sleepiness in the USA. OSA results from poor oropharyngeal tone and is also associated with depression and morning headaches.

Obstructive sleep apnea refers to physical airway obstruction during sleep, often due to decreased pharyngeal muscle tone or excessive soft tissue impinging on the upper airway. Patients with OSA have the following cardinal features: irregular/abnormal respiratory patterns during sleep (e.g. obstructive apneas or hypopneas), loud snoring, signs of disturbed sleep (often observed by others), and symptoms attributable to disturbed sleep (e.g. sleepiness, depression). Risk factors for OSA include older age, male gender, obesity, craniofacial abnormalities, and upper airway soft tissue abnormalities. Diagnosing and treating OSA is essential; if untreated, it can have significant adverse effects on daytime function and cognition and can raise the risk of a number of cardiovascular events (including pulmonary artery hypertension, systemic hypertension, and cardiac arrhythmias).

Ramar and Olson provide a broad overview of sleep disorders. OSA should be suspected in patients with snoring and witnessed apneas. The diagnosis of OSA is made formally with overnight polysomnography. The mainstay of treatment is continuous positive airway pressure (CPAP). For obese individuals, weight loss can also contribute significantly to improvement in OSA.

Okubo et al. aimed to evaluate the cost-effectiveness of OSA screening for patients with diabetes and CKD. This type of screening has proven to be cost-effective for patients with cardiovascular disease such as hypertension. They report that active case screening and treatment of OSA for untreated middle-aged male patients with diabetes or CKD is indeed cost-effective based on cost-effectiveness analysis and Markov modeling.

Illustration A depicts a mnemonic/screening tool for sleep apnea provided by the American Sleep Apnea Association. Illustration B depicts the multitude of adverse outcomes related to untreated OSA.

Incorrect Answers:
Answer 1: Insufficient sleep duration is unlikely to be the cause of this patient's daytime sleepiness, as he is sleeping for 8-9 hours (albeit with disruption due to apnea).
Answer 2: A circadian rhythm sleep-wake disorder would include syndromes such as jet lag or delayed sleep-wake phase disorder; these are not likely given the clinical history.
Answer 4: Deficiency of the neuropeptides, orexin-A and orexin-B, describes the pathophysiology of narcolepsy, which this patient does not have (e.g. no loss of muscle tone nor hypnopompic hallucinations).
Answer 5: Daytime sleepiness can be associated with primary psychiatric disorders such as depression; however, in this case the patient's depression likely stems first and foremost from his underlying OSA.