Cataplexy

Cataplexy
Specialty	Neurology

Cataplexy is sudden and transient episode of loss of muscle tone, often triggered by emotions. It frequently affects people who have narcolepsy, a disorder whose principal signs are EDS (Excessive Daytime Sleepiness), sleep attacks, sleep paralysis, hypnagogic hallucinations and disturbed night-time sleep. Cataplexy is sometimes confused with epilepsy, where a series of flashes or other stimuli cause superficially similar seizures. Cataplexy can also present as a side effect of SSRI Discontinuation Syndrome.

The term cataplexy originates from the Greek "kata", meaning down, and plexis, meaning a stroke or seizure.

Presentation

Cataplexy manifests itself as muscular weakness which may range from a barely perceptible slackening of the facial muscles to the dropping of the jaw or head, weakness at the knees, or a total collapse. Usually the speech is slurred, vision is impaired (double vision, inability to focus), but hearing and awareness remain normal. These attacks are triggered by strong emotions such as exhilaration, anger, fear, surprise, orgasm, awe, embarrassment, and laughter. Cataplexy may be partial or complete, affecting a range of muscle groups, from those controlling facial features to (less commonly) those controlling the entire body.

• Arm weakness
• Sagging jaw
• Drooping head
• Slumping of the shoulders
• Slurred speech
• Generalized weakness
• Knee buckling

When cataplexy happens often, or cataplexy attacks make patients fall or drop things, it can have serious effects on normal activities. It can cause accidents and be embarrassing when it happens at work or with friends. For example, narcoleptics may not pick up babies because they are afraid they may drop them.

Treatment

Despite its relation to narcolepsy, in most cases, cataplexy must be treated differently and separate medication must be taken. For many years, cataplexy has been treated with tricyclic antidepressants such as imipramine, clomipramine or protriptyline. However these can have unpleasant side-effects and so have been generally replaced by newer drugs such as venlafaxine, a more recent antidepressant. Xyrem, the brand-name of the compound (sodium)gamma-Hydroxybutyrate GHB, has been shown to treat not only cataplexic attacks, but in narcoleptics, it has also been shown to significantly reduce daytime sleepiness. Monoamine oxidase inhibitors may be used to manage both cataplexy and the REM sleep-onset symptoms of sleep paralysis and hypnagogic hallucinations.

A person's efforts to stave off cataplectic attacks by avoiding these emotions may greatly diminish their lives, and they may become severely restricted emotionally if diagnosis and treatment is not begun as soon as possible.

Diagnosis

Cataplexy in severe cases can cause vital signs to be hard to detect without a continuous auditory pulse oximeter. As an anecdotal example, one Allison Burchell, a sufferer of severe Cataplexy, has been pronounced dead three times.

See also

• Neurodegenerative disease
  • Niemann Pick disease

In the media

• Recently, The Learning Channel (TLC) aired an episode of "My Shocking Story: I Woke Up in a Morgue" which detailed several cases of cataplexy.
• On Tuesday, August 5th, 2008 BBC News ran a story about a young woman who collapses when she laughs, in attempts to raise awareness about cataplexy.

External links

• Center for Sleep Research, Siegel Lab, UCLA
• Narcolepsy Association UK
• BBC's Article on the condition
• National Niemann Pick Disease Foundation: Children with Niemann Pick Type C often suffer from cataplexy
• Video of patient with cataplexy