WBR0424

Author	[[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry
Sub Category	SubCategory::Pulmonology
Prompt	[[Prompt::A 43-year-old male, diagnosed with hypertension, is recommended to undergo polysomnography in order to rule out secondary hypertension caused by obstructive sleep apnea. While analyzing the polysomnogram, you note the beginning of a sleep stage characterized by sleep spindles and K complexes. Which of the following findings is most likely to be present in the patient during this stage of sleep?]]
Answer A	AnswerA::Rapid eye movement
Answer A Explanation	AnswerAExp::Rapid eye movement, dreaming, erections, and loss of motor tonicity frequently manifest during REM sleep.
Answer B	AnswerB::Bruxism
Answer B Explanation	AnswerBExp::Bruxism frequently manifests in stage 2 of sleep, characterized by sleep spindles and K complexes upon 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 are usually present 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, reported in approximately 8% of the adult population, is the clenching of teeth due to rhythmic masticatory muscle movement (RMMA) with repetitive jaw muscle contractions. Bruxism may cause tooth destruction, jaw pain, limited movement of the mandible, and headaches. Although bruxism can occur in all stages of sleep, it is most frequently occurs during stages 1 and 2 of sleep. Sleep spindles and K complexes are characteristic findings of stage 2 of sleep on polysomnography. Educational Objective: Sleep bruxism, or teeth clenching, usually occurs 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. Critical Reviews in Oral Biology and Medicine. 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. Journal of Dental Research. 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
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