Identifying Genuine Cataplexy in Narcolepsy
- Aug 10
- 4 min read
Identifying genuine cataplexy can be complicated because a number of other conditions can also cause episodes of temporary muscle weakness, loss of muscle control or falls. Other symptoms commonly associated with narcolepsy, including excessive daytime sleepiness and fatigue, can also occur in people with other disorders. For this reason, establishing a clear history of the episodes themselves is important. [4]
Cataplexy has a characteristic clinical pattern. Looking carefully at what triggers an episode, what happens during it, how long it lasts, whether consciousness is preserved, which parts of the body are affected and what happens immediately afterwards can help distinguish genuine cataplexy from episodes that have another cause. [1,4]
What is cataplexy?
Cataplexy is a sudden, involuntary loss of muscle tone or muscle control that occurs while a person is awake. It can range from partial muscle weakness to complete paralysis. [1,2]
• Consciousness is preserved. The person remains awake and conscious and can remember what happened before, during and after the episode. [1,2]
• Triggered by strong emotion, most characteristically positive emotions such as laughter, amusement, excitement, joking or surprise. Anger can also trigger cataplexy, but less often. [1–3]
• Attacks are brief, a few seconds to less than two minutes. [1]
• Loss of muscle tone is always bilateral. This means both sides of the body are affected, even if one side is more affected than the other. [2]
• Frequency varies. Usually occurs at least once a month but can be several times a day if untreated. [1]
• Recovery is immediate. Muscle activity returns abruptly after the episode and the person returns to normal. [1]
• Breathing muscles remain unaffected, although some people may experience a sensation of breathlessness. [2]
• Deep tendon reflexes are temporarily lost in the affected limbs during an episode and return afterwards. [5]
Cataplexy can appear to last longer when an emotional trigger continues and repeated attacks merge together. [1,2]
Partial attacks can involve the face, jaw, head, neck, arms or legs. They may cause the jaw to sag, the head to drop, speech to become slurred, the face to slacken or the knees to buckle. [1,2]
Complete cataplexy is less common. When cataplexy affects the whole body, loss of muscle tone generally starts in the face or neck and builds over several seconds. This can make the person unable to stand and may result in a fall. Muscle tone returns abruptly after the attack. [1,2]
When the pattern does not fit
If two or more of these unusual characteristics are present, the episodes should not be labelled as cataplexy. [1]
• Uncertainty about whether consciousness was preserved
• Weakness affecting only one side of the body
• Episodes never triggered by laughter, joking or amusement
• Very rapid whole-body muscle weakness with no build-up over several seconds, may lead to falls and injuries
• No clear emotional trigger, or only negative emotions or stimuli as triggers (such as anxiety, fear, stress or being startled by an unexpected noise)
• Episodes lasting several minutes without an ongoing trigger
• Needing several minutes or more to recover afterwards
• Only ever having complete attacks, with no history of partial cataplexy
Features that are not compatible with cataplexy include: [1]
• Loss or alteration of consciousness from the beginning of the episode
• Episodes lasting more than 10 minutes without a continuing trigger
• Warning symptoms typical of fainting, such as warmth, sweating, dizziness, ringing in the ears, changes in vision or hearing, nausea or tingling
• Altered consciousness, nausea or continuing muscle weakness after the episode
What else can look like cataplexy?
Other conditions or events can cause weakness, falls or collapse and may be mistaken for cataplexy. These include syncope (fainting), seizures, drop attacks, neuromuscular disorders, vestibular disorders, transient ischaemic attacks (TIAs), functional neurological disorder, sleep attacks and sleep paralysis. [4]
If you pass out, black out, lose consciousness or have unexplained episodes of weakness, falls or collapse, speak to your doctor so the cause can be investigated. |
Cataplexy in children can look different
Cataplexy in children can look quite different from the typical adult pattern, particularly close to the onset of narcolepsy. It can be severe and may include both loss of muscle tone and additional movements. [1,7,8]
Children may experience:
• Facial weakness, drooping eyelids, repeated mouth opening or tongue protrusion — sometimes referred to as cataplectic facies [1,8]
• Head dropping, generalised low muscle tone or an unsteady, wide-based gait [1,8]
• Additional movements such as facial twitching or grimacing, swaying, repetitive or other involuntary movements [1,8]
• Facial weakness that can sometimes be more continuous rather than occurring only as separate attacks [1,8]
• Episodes where an emotional trigger is not always obvious, particularly near disease onset [1,7,8]
These childhood features often become less prominent with time, with cataplexy developing the more familiar pattern seen in adults. [8]
Suspected cataplexy in a child or adolescent should be assessed by someone familiar with paediatric narcolepsy. [6]
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2. Dauvilliers Y, Siegel JM, Lopez R, Torontali ZA, Peever JH. Cataplexy—clinical aspects, pathophysiology and management strategy. Nat Rev Neurol. 2014;10(7):386–395. doi:10.1038/nrneurol.2014.97.
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5. Barateau L, Pizza F, Lopez R, Antelmi E, Plazzi G, Dauvilliers Y. Persistence of deep-tendon reflexes during partial cataplexy. Sleep Med. 2018;45:80–82. doi:10.1016/j.sleep.2017.12.011.
6. Maski K, Owens JA. Pediatric Sleep Disorders. Continuum (Minneap Minn). 2018;24(1, Child Neurology):210–227. doi:10.1212/CON.0000000000000566.
7. Aran A, Einen M, Lin L, Plazzi G, Nishino S, Mignot E. Clinical and therapeutic aspects of childhood narcolepsy-cataplexy: a retrospective study of 51 children. Sleep. 2010;33(11):1457–1464. doi:10.1093/sleep/33.11.1457.
8. Plazzi G, Pizza F, Palaia V, et al. Complex movement disorders at disease onset in childhood narcolepsy with cataplexy. Brain. 2011;134(Pt 12):3477–3489. doi:10.1093/brain/awr244.
