Cataplexy
Cataplexy is specifically indicative of narcolepsy and is the best diagnostic marker of the disease.
Definition: Cataplexy is defined as a sudden episode of bilateral muscle weakness triggered by the onset of strong emotions (e.g. laughter, anger, frustration, excitement, embarrassment, surprise, stress, or sexual arousal)
- In healthy individuals, this motor suppression occurs during normal REM sleep.
- In individuals with narcolepsy, this also happens outside of sleep and presents as a cataplectic attack.
o For these patients, additional medications are often used to reduce the incidence and severity of cataplexy.
It is characterized by severe, irresistible daytime sleepiness and sudden loss of muscle tone; it can be associated with sleep- onset or sleep-offset paralysis and hallucinations, frequent movement and awakening during sleep, and weight gain. Cataplexy worsens with poor sleep and fatigue.
Prevalence
The prevalence of cataplexy among patients with narcolepsy varies widely, with estimates ranging from 60 – 90% of narcoleptics.
Signs and Symptoms
Cataplectic attacks are variable, but are usually mild in severity. Most cataplexy attacks are partial attacks and affect only certain muscle groups:
- Buckling or unlocking of the knees
- Head or jaw dropping
- Facial muscle flickering
- Sagging of the jaw or weakness in the arms
- Garbled speech and voice
Generalized cataplexy tends to be severe and may cause the patient to collapse to the ground. Falls and injury associated with cataplexy are rare, and most often the patient will have time to find support or will sit down while the attack is occurring.
Cataplexy attacks do not affect the diaphragm, respiratory, and extra-ocular muscles, even when these episodes are severe. During an episode, the patient is awake and aware of their surroundings but is unable to move. As patients are conscious during the episode, they can recall the details of the event.
Cataplectic episodes are often subjective feelings that are difficult to describe, such as a feeling of warmth or that somehow time has suspended. Since most cataplectic episodes last for a few seconds, they tend to be imperceptible to the observer.
Onset, Duration, and frequency
The onset of cataplexy occurs within five years after the occurrence of daytime somnolence in approximately two-thirds of cases. The duration of cataplexy varies from a split second to several minutes, and its frequency varies from less than one episode per year to several episodes per day. However, patients can occasionally experience “status cataplecticus”, which comprises continual cataplectic episodes lasting several hours. This state can occur spontaneously but is more often seen on withdrawal from anticataplectic antidepressant drugs like tricyclic antidepressants, which can also be used to treat cataplexy.
Progression
Cataplexy often improves with advancing age; in rare cases, it disappears completely, but in most patients it becomes better controlled (probably after the patient has learned to control his emotions). Interestingly, a decline in cataplexy over time may indicate that patients have become better at adapting to their illness and have learned to avoid situations that trigger cataplexy.
Definition: Cataplexy is defined as a sudden episode of bilateral muscle weakness triggered by the onset of strong emotions (e.g. laughter, anger, frustration, excitement, embarrassment, surprise, stress, or sexual arousal)
- In healthy individuals, this motor suppression occurs during normal REM sleep.
- In individuals with narcolepsy, this also happens outside of sleep and presents as a cataplectic attack.
o For these patients, additional medications are often used to reduce the incidence and severity of cataplexy.
It is characterized by severe, irresistible daytime sleepiness and sudden loss of muscle tone; it can be associated with sleep- onset or sleep-offset paralysis and hallucinations, frequent movement and awakening during sleep, and weight gain. Cataplexy worsens with poor sleep and fatigue.
Prevalence
The prevalence of cataplexy among patients with narcolepsy varies widely, with estimates ranging from 60 – 90% of narcoleptics.
Signs and Symptoms
Cataplectic attacks are variable, but are usually mild in severity. Most cataplexy attacks are partial attacks and affect only certain muscle groups:
- Buckling or unlocking of the knees
- Head or jaw dropping
- Facial muscle flickering
- Sagging of the jaw or weakness in the arms
- Garbled speech and voice
Generalized cataplexy tends to be severe and may cause the patient to collapse to the ground. Falls and injury associated with cataplexy are rare, and most often the patient will have time to find support or will sit down while the attack is occurring.
Cataplexy attacks do not affect the diaphragm, respiratory, and extra-ocular muscles, even when these episodes are severe. During an episode, the patient is awake and aware of their surroundings but is unable to move. As patients are conscious during the episode, they can recall the details of the event.
Cataplectic episodes are often subjective feelings that are difficult to describe, such as a feeling of warmth or that somehow time has suspended. Since most cataplectic episodes last for a few seconds, they tend to be imperceptible to the observer.
Onset, Duration, and frequency
The onset of cataplexy occurs within five years after the occurrence of daytime somnolence in approximately two-thirds of cases. The duration of cataplexy varies from a split second to several minutes, and its frequency varies from less than one episode per year to several episodes per day. However, patients can occasionally experience “status cataplecticus”, which comprises continual cataplectic episodes lasting several hours. This state can occur spontaneously but is more often seen on withdrawal from anticataplectic antidepressant drugs like tricyclic antidepressants, which can also be used to treat cataplexy.
Progression
Cataplexy often improves with advancing age; in rare cases, it disappears completely, but in most patients it becomes better controlled (probably after the patient has learned to control his emotions). Interestingly, a decline in cataplexy over time may indicate that patients have become better at adapting to their illness and have learned to avoid situations that trigger cataplexy.
References
Ahmed I, Thorpy M. Clinical features, diagnosis and treatment of narcolepsy. Clin Chest Med 2010; 31: 371 – 381
Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Medicine 2007; 2: 373 – 399
Dauvilliers Y., Arnulf I, Mignot E. Narcolepsy with Cataplexy. Lancet (Seminar) 2007; 369: 499 – 511
Houghton WC, Scammell TE, Thorpy M. Pharmacotherapy for cataplexy. Sleep Medicine Reviews 2004; 8: 355-3662.
Images:
http://bouldersleeptherapy.com/disorders/narcolepsy.php/
autoimmunediseasesa2z.com
www3.unil.ch
Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Medicine 2007; 2: 373 – 399
Dauvilliers Y., Arnulf I, Mignot E. Narcolepsy with Cataplexy. Lancet (Seminar) 2007; 369: 499 – 511
Houghton WC, Scammell TE, Thorpy M. Pharmacotherapy for cataplexy. Sleep Medicine Reviews 2004; 8: 355-3662.
Images:
http://bouldersleeptherapy.com/disorders/narcolepsy.php/
autoimmunediseasesa2z.com
www3.unil.ch