WBR0424

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D. and Alison Leibowitz [1])]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry
Sub Category	SubCategory::Pulmonology
Prompt	[[Prompt::A 43 year-old obese man presents to the physician's office with recurrent occipital headaches and blurry vision. The patient explains that he has had multiple blood pressure measurements in the past, all of which were in the hypertensive range. Upon further questioning, the patient's wife states that her husband snores very loudly and wakes up unconsciously several times during his sleep. The physician recommends the patient undergoes polysomnography to evaluate for secondary causes of hypertension. While analyzing the polysomnogram, the physician notes the beginning of a sleep stage characterized by sleep spindles and K complexes. Which of the following clinical findings is mostly associated with this stage of sleep?]]
Answer A	AnswerA::Rapid eye movement
Answer A Explanation	[[AnswerAExp::Dreaming, penile erections, and loss of motor tonicity manifest during REM sleep.]]
Answer B	AnswerB::Teeth clenching
Answer B Explanation	[[AnswerBExp::Bruxism (teeth clenching/grinding) frequently manifests during stage 2 of sleep, which is characterized by sleep spindles and K complexes on polysomnography.]]
Answer C	AnswerC::Bedwetting
Answer C Explanation	[[AnswerCExp::Bedwetting, night terrors, and sleep walking frequently manifest during stage 3 of sleep.]]
Answer D	AnswerD::Night terrors
Answer D Explanation	AnswerDExp::Night terrors usually manifest during stage 3 of sleep.
Answer E	AnswerE::Penile erection
Answer E Explanation	[[AnswerEExp::Penile erections, dreaming, erections, and loss of motor tonicity frequently manifest during REM sleep.]]
Right Answer	RightAnswer::B
Explanation	[[Explanation::Sleep bruxism (teeth clenching/grinding) is reported among approximately 8% of the adult population. It is defined as the clenching of teeth that occurs during sleep due to rhythmic masticatory muscle movement with repetitive jaw muscle contractions. Bruxism may be a destructive process that causes tooth destruction, jaw pain, limited movement of the mandible, and headaches. Although bruxism may occur in all stages of sleep, it is more frequently observed in stages 1 and 2 than in slow-wave sleep or in rapid eye movement (REM) sleep. Sleep spindles and K complexes are characteristic findings of stage 2 of sleep on polysomnography. Educational Objective: Sleep bruxism (teeth clenching/grinding) usually manifests during stage 2 of sleep, which is characterized by sleep spindles and K complexes on polysomnography. References: Lavigne GJ, Kato T, Kolta A, et al. Neurobiological mechanisms involved in sleep bruxism. Crit Rev Oral Biol Med. 2003;14(1):30-46 Macaluso GM, Guerra P, Di Giovanni G, et al. Sleep bruxism in a disorder related to periodic arousals during sleep. J Dent Res. 1998;77(4):565-573]]
Approved	Approved::Yes
Keyword	WBRKeyword::Bruxism, WBRKeyword::Polysomnography, WBRKeyword::Sleep, WBRKeyword::K complex, WBRKeyword::Sleep spindles, WBRKeyword::REM, WBRKeyword::Sleep stages, WBRKeyword::Teeth clenching, WBRKeyword::Teeth grinding
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