Cataplexy

Cataplexy is an episode of muscular weakness triggered by strong emotions such as laughter, anger and surprise. The loss of muscle tone ranges from a just-perceptible weakening of the facial muscles through weakness at the knees, to total collapse on the floor. Speech is slurred, eyesight impaired (double vision, inability to focus) but hearing and awareness remain undisturbed. Attacks often last less than 2 minutes (see here), and they may only last a few seconds. Some people have repeated attacks of cataplexy which persist for up to 30 minutes. During both mild and severe attacks, the person stays fully conscious.

Cataplexy may be most severe when the subject is tired rather than fully alert and can lead to considerable anxiety although anxiety itself is not a trigger. It is thought that about 75% of patients with narcolepsy have cataplexy. Rarely, it is the first symptom of narcolepsy but typically it does not develop for months or even years after the firs signs of excessive daytime sleepiness.

Essentially, cataplexy is a symptom only found in narcolepsy and thus the presence of it makes diagnosis of narcolepsy much more certain.

Management

Both children and adults need to interact with the patient to learn when and how to help the patient during a cataplectic attack. Family members need to learn when the patient may be in danger, pain, or otherwise need assistance. The patient will usually have individual preferences about whether he or she wants to be touched, supported, assisted, or simply left alone during attacks. In most cases, the patient will prefer to recover spontaneously.

Adult members of the family can benefit from assurances that the attacks are not related to epilepsy and are manifestations of REM sleep intrusion into the waking state

Full-blown cataplectic attacks can be frightening to family members. Special attention must be given to the emotional impact on the patient's children. Children sometimes interpret the occasional grimaces, erratic body movements, or unintelligible words that may occur during the attack as signs that their parent is in great pain or may die. They may also experience overwhelming feelings of helplessness. Counselling is very important to assist the child with the pain and terror she or he may be feeling.

The family's routine acceptance of the attack can do much to reduce embarrassment when attacks occur in public. The following illustrates how family members can interact during narcoleptic attacks. A woman with narcolepsy was dining in a restaurant with friends and family. During the meal she experienced several attacks. Her daughter was aware of her mother's condition and during each attack she stood behind her mother providing support for the head and shoulders until the attack had passed. Since family members accepted the situation calmly and did only what was necessary to prevent injury, everyone else in the restaurant remained calm. After the first few attacks, the other diners paid no further attention to the incidents.

Communication between family members is very important and can keep cataplectic attacks from being unnecessarily upsetting and disruptive for both the patient and family.

Induced

The table below summarises the response from a group of subjects with narcolepsy who were asked what were the most common ways in which their cataplexy was triggered. Laughter and anger precipitated cataplexy in almost all the patients.

(Adapted from Guilleminault C et al Arch Neurol. 1974 31: 255-261.)

Duration

The graph below summarises the duration of attacks of cataplexy in a group of sujects with narcolepsy.

(Adapted from Narcolepsy Eds: Guilleminault C et al, New York:Spectrum Publications, 1976)

As can be seen from the graph above most attacks of cataplexy are transient, being terminated within one minute. However in some instances they can persist for up to 20 minutes. In very rare cases the individual may suffer from prolonged cataplexy - a condition known as status cataplecticus.