A 68-year-old man is brought to the primary care physician's office by his wife. She reports that the patient has been flailing in his sleep, particularly during the early morning hours. She is worried that he will hurt himself or her with these movements. The episodes started several months ago with infrequent nighttime movements but now occur almost nightly. The patient's wife says, "It's like he can't control himself. I have seen him kicking in bed, pushing over the nightstand, and moving furniture out of the way. He has also tried to push me from behind with his whole body, all while appearing to be asleep." She is able to wake him from these episodes, and he doesn't appear disoriented or confused on awakening. The patient is unaware of his nighttime movements but describes a recurrent dream in which he feels lost and trapped in the woods and tries to escape. He has had no behavioral symptoms while awake during the day. His only other symptom is constipation. The patient's medical history includes well-controlled hypertension. Vital signs are within normal limits, and physical examination is normal except for slight slowness of gait. Which of the following is the most likely diagnosis?

Question

A 68-year-old man is brought to the primary care physician's office by his wife.  She reports that the patient has been flailing in his sleep, particularly during the early morning hours.  She is worried that he will hurt himself or her with these movements.  The episodes started several months ago with infrequent nighttime movements but now occur almost nightly.  The patient's wife says, "It's like he can't control himself.  I have seen him kicking in bed, pushing over the nightstand, and moving furniture out of the way.  He has also tried to push me from behind with his whole body, all while appearing to be asleep."  She is able to wake him from these episodes, and he doesn't appear disoriented or confused on awakening.  The patient is unaware of his nighttime movements but describes a recurrent dream in which he feels lost and trapped in the woods and tries to escape.  He has had no behavioral symptoms while awake during the day.  His only other symptom is constipation.  The patient's medical history includes well-controlled hypertension.  Vital signs are within normal limits, and physical examination is normal except for slight slowness of gait.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by complex motor behaviors that occur during REM sleep. Normal REM sleep is characterized by muscle atonia. However, in RBD, degeneration of the brainstem nuclei responsible for inhibiting spinal motor neurons during normal REM sleep leads to incomplete or absent muscle atonia, facilitating dream enactment behaviors. These behaviors are more likely to occur during the latter half of the night, when the relative percentage of REM sleep is higher. Patients can usually be awakened fairly easily and are alert and oriented. They may not recall their movements during sleep but can often recall their dreams. RBD is more likely to occur in older adult men. If frequent and recurrent, it may be a prodromal sign of neurodegeneration with risk of subsequent onset of Parkinson disease or dementia with Lewy bodies. RBD is frequently accompanied by prodromal signs/symptoms of neurodegeneration such as subtle motor deficits (eg, slowed gait), anosmia, or constipation. Narcolepsy and antidepressant medication initiation are also associated with RBD. (Choice A) Nightmare disorder involves vivid recall of disturbing dream content. However, unlike RBD, it is not associated with motor activity or sleep-related injury. (Choice B) Nocturnal seizures are characterized by repetitive and stereotypical movements. They most frequently occur during non-REM sleep, a stage of sleep that is densest during the first half of the night, and are associated with postictal confusion on awakening. (Choice C) Obstructive sleep apnea presents with nighttime apneas, snoring, daytime sleepiness, or arousals related to respiratory effort. (Choice E) Restless legs syndrome involves an overwhelming urge to move the legs and is commonly associated with sleep disturbance and involuntary, jerking movements of the legs during sleep. It would not explain this patient's dream enactment with complex motor behaviors. (Choices F and G) Sleep terrors and sleepwalking are examples of non-REM sleep arousal disorders that typically occur in younger patients during slow-wave (N3), non-REM sleep. In contrast to RBD, they typically occur during the first third of the sleep period. On awakening, there is a longer period of confusion before becoming fully alert, and individuals do not recall any concurrent dreams. Educational objective: Rapid eye movement (REM) sleep behavior disorder involves dream enactment that occurs during REM sleep due to absence of muscle atonia. If awakened, patients become fully alert and recall their dreams. In older patients, these behaviors may be a sign of neurodegeneration. References: REM sleep behaviour disorder. (http://www.ncbi.nlm.nih.gov/pubmed/26427638) REM sleep behavior disorder. (http://www.ncbi.nlm.nih.gov/pubmed/20451035)

A 68-Year-Old Man Is Brought to the Primary Care Physician's