Cataplexy

Definition

Cataplexy is a sudden, brief episode of muscle weakness or paralysis triggered by strong emotions, such as laughter, surprise, or anger. It is a key symptom associated with the sleep disorder narcolepsy.

5 Must Know Facts For Your Next Test

1. Cataplexy is triggered by strong positive or negative emotions, causing a sudden loss of muscle tone that can range from slight facial muscle weakness to complete body collapse.
2. Cataplexy episodes typically last less than two minutes and the person remains fully conscious during the attack.
3. Cataplexy is closely associated with the sleep disorder narcolepsy, and is considered a hallmark symptom of the condition.
4. Individuals with narcolepsy and cataplexy often experience their first cataplectic episode in childhood or adolescence.
5. The underlying cause of cataplexy is believed to be a dysfunction in the neural pathways that regulate REM sleep and muscle tone.

Review Questions

• Explain the relationship between cataplexy and the sleep disorder narcolepsy.
  • Cataplexy is a key symptom of the sleep disorder narcolepsy. Individuals with narcolepsy experience sudden, temporary muscle weakness or paralysis triggered by strong emotions, such as laughter or surprise. This cataplectic episode is caused by a dysfunction in the neural pathways that regulate REM sleep and muscle tone. Cataplexy is considered a hallmark symptom of narcolepsy, and the presence of cataplexy is often used to help diagnose the condition.
• Describe the typical characteristics and duration of a cataplectic episode.
  • During a cataplectic episode, the individual experiences a sudden, brief loss of muscle tone that can range from slight facial muscle weakness to complete body collapse. These episodes are typically triggered by strong positive or negative emotions, such as laughter, surprise, or anger. Cataplectic episodes usually last less than two minutes, and the person remains fully conscious throughout the attack. The sudden muscle weakness is caused by a temporary disruption in the neural pathways that control muscle tone, which is normally suppressed during REM sleep.
• Analyze the potential underlying causes and risk factors associated with cataplexy.
  • The primary underlying cause of cataplexy is believed to be a dysfunction in the neural pathways that regulate REM sleep and muscle tone. Specifically, a deficiency or imbalance in the neurotransmitter hypocretin/orexin, which plays a crucial role in maintaining wakefulness and REM sleep regulation, has been linked to the development of both narcolepsy and cataplexy. Individuals with narcolepsy and cataplexy often experience their first cataplectic episode in childhood or adolescence, suggesting that genetic and environmental factors may also contribute to the risk of developing this condition. Understanding the complex interplay between sleep regulation, emotion, and muscle tone is essential for identifying potential risk factors and developing effective treatments for cataplexy.

Related terms

Narcolepsy: A chronic sleep disorder characterized by excessive daytime sleepiness, sudden loss of muscle tone (cataplexy), sleep paralysis, and hallucinations during sleep-wake transitions.

Sleep Paralysis: A temporary inability to move or speak that occurs when waking up or falling asleep, often accompanied by a sense of an evil presence in the room.

Hypocretin/Orexin: A neuropeptide that plays a crucial role in regulating wakefulness and REM sleep; deficiency in hypocretin/orexin is linked to the development of narcolepsy and cataplexy.