Cataplexy Possibly Associated With Lamotrigine

Prevalence and incidence of narcolepsy symptoms in the US general population

Objective

The objectives of this study are to evaluate the prevalence and incidence of Narcolepsy type 1 and type 2 and to determine the prevalence of narcolepsy diagnosis criteria in the US general population.

Methods

This longitudinal study was conducted in the adult US general population in two occasions. The initial interviews included 15 states (Arizona, California, Colorado, Florida, Idaho, Missouri, New York, North Carolina, North Dakota, Oregon, Pennsylvania, South Dakota, Texas, Washington, and Wyoming). The follow-up interviews, was done three years later in eight of these states. Of the 19,136 contacted individuals, 15,929 completed the initial interview and 10,931 completed the follow-up. Participants were interviewed using the Sleep-EVAL system, an artificial intelligence tool. Narcolepsy Type 1 (with cataplexy) and Narcolepsy Type 2 (without cataplexy) were defined according to the ICSD-3 classification. Symptoms of narcolepsy were assessed by frequency per week and duration. Medical visits and diagnoses were also collected.

Results

Participants were aged between 18 and 102 years of age (mean 45.8 ± 17.9 years), 51.3 % were women. The prevalence of narcolepsy with cataplexy was 12.6 per 100,000 individuals (95 % C.I., 0 to 30) and narcolepsy without cataplexy was 25.1 per 100,000. The incidence per year was 2.6 per 100,000 individuals (95 % C.I., 0 to 11).

Conclusions

Narcolepsy is a rare condition affecting 37.7/100,000 individuals (126,191 individuals in the current US population). Our US general population prevalence is in line with rates found in community-based studies but lower than what is reported in claim database studies.

Therapy for Cataplexy

Purpose of the review

Cataplexy, an involuntary loss of muscle activity triggered by strong emotions is the most impressive symptom in narcolepsy. This review gives an overview of the current understanding of cataplexy and its available treatment options.

Recent findings

With the discovery of hypocretin/orexin, the understanding of the pathophysiology of cataplexy advanced in the past decades. In the recent years, with the development of new anticataplectic agents (e.g., Pitolisant) symptomatic treatment of cataplexy has further improved. Abrupt cessation of anticataplectic medication especially antidepressants increase the risk of status cataplecticus, a virtually continuous series of long-lasting cataplectic attacks.

Summary

Cataplexies still remain an under-recognized phenomenon due to missing diagnostic measures. Treatment for cataplexy still remains symptomatic but new agents with better tolerability and usability are continuously developed. New therapeutic actions either targeting the autoimmune mechanisms underlying orexin cell death or substituting orexin action are promising treatments for the near future.

Thinking outside the box: cataplexy without narcolepsy

Cataplexy is a transient loss of muscle tone that can be triggered by emotions such as laughter, excitement or fear. Other causes of cataplexy include Niemann-Pick type C Disease, Angelman Syndrome, Norrie Disease, Prader-Willi Syndrome. In addition, cataplexy can be a side effect of several drugs (eg, lamotrigine, clozapine, and gamma-hydroxybutyrate). Yet, the most prevalent causes of cataplexy without narcolepsy are rare genetic diseases; which explains why cataplexy is classically linked to narcolepsy. Therefore, it is essential disconnecting cataplexy from narcolepsy especially in pediatric population and after use of a few medications. In this review, we described few conditions of cataplexy not related to narcolepsy. We performed a review of literature (MEDLINE and EMBASE database), without limited date or publication restrictions.