The parents of a 7-year-old boy are alarmed by his sudden loud screaming and crying shortly after he falls asleep. He sits up in bed, seems very distressed, and does not wake up when touched or gently shaken. On rare occasions, he wakes up, appears confused, and has no recollection for the events. His recent pediatric workup was all within normal limits and your physical evaluation is unrevealing.
Which of the following is the most likely diagnosis?A. Sleep terror
B. REM behavior disorder
D. Noctural panic episode
Answer: A. Sleep terror
Sleep terror is an example of a non-REM parasomnia, best conceptualized as a series of partial or incomplete arousals from deep sleep. During these events, states of sleep and wakefulness coexist and are mixed with one another. The patient is in a state which lies between deep sleep and full wakefulness-partially asleep and partially awake. These disorders are more common in childhood than adulthood and decrease in frequency after age 5 years.
Sleep terror attacks arise abruptly, usually during the first third of the night. Although typically the attacks represent partial arousals from deep, slow wave sleep, occasionally sleep terrors may arise from other stages of non-REM sleep and occur during daytime naps. The individual sits up with an expression of terror, emits a piercing scream, and appears frightened and inconsolable. He usually displays autonomic arousal with rapid breathing, tachycardia, sweating, dilated pupils, and increased muscle tone. He also looks awake, but typically is unresponsive to environmental stimuli, and if awakened, is disoriented and confused. The typical duration is between 30 seconds and 3 minutes, and at the end of an attack, the person usually returns to sleep.
There is usually amnesia for the episode, although occasionally amnesia is not complete and individuals may report a vague image or sound. Attacks may be triggered by sleep-disruptive phenomena such as untreated apneas, periodic limb movements, pain, full bladder, and environmental noise. There is a strong genetic component, and individuals commonly report a family history of sleep terrors and other arousal disorders. The prevalence of sleep terrors has been reported between 1% and 7% in children and 2% in adults.
REM behavior disorder differs from sleep terror in that the former typically occurs in later life, and is associated with vivid dreaming during nocturnal behavioral episodes. Cataplexy is a loss of voluntary muscle control in response to emotional stimuli and occurs almost exclusively in the context of narcolepsy. Nocturnal panic episodes are typically associated with awakening from sleep and patients are typically responsive and can be aroused.
Broughton RJ. NREM arousal parasomnias. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. Philadelphia: WB Saunders Company; 2000:693-706.
Ohayon MM, Guilleminault C, Priest RG. Night terrors, sleepwalking, and confusional arousals in the general population: their frequency and relationship to other sleep and mental disorders. J Clin Psychiatry. 1999;60:268-276.