Cataplexy

Cataplexy
Specialty	Neurology

Not to be confused with Catalepsy.

Cataplexy is a sudden and transient episode of loss of muscle tone, often triggered by emotions. It is a rare disease (prevalence of fewer than 5 per 10,000 in the community), but affects roughly 70% of people who have narcolepsy. Cataplexy can also be present as a side effect of SSRI Discontinuation Syndrome.

The term cataplexy originates from the Greek κατά (kata, meaning "downwards"), and πληξις (plēxis, meaning "striking" or "hitting" [from plessein meaning "to strike or hit"]).

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

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, people with cataplexy 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.

For cataplexy associated with narcolepsy, Xyrem (sodium oxybate) is often recommended.

Monoamine oxidase inhibitors may be used to manage both cataplexy and the REM sleep-onset symptoms of sleep paralysis and hypnagogic hallucinations.

Emerging Therapies

Emerging therapies include Hypnotic Psychotherapy, Hypocretin Gene Therapy, and Hypocretin Cell Transplantation for narcolepsy-cataplexy.

See also

• Neurodegenerative disease
  • Niemann Pick disease

External links

• Wake Up Narcolepsy's Description of Cataplexy
• Narcolepsy Association UK
• BBC's Article on the condition
• National Niemann Pick Disease Foundation: Children with Niemann Pick Type C often suffer from cataplexy