AHMF: 98 Conference: Pearn

Models for CFS - Channelopathies And Ciguatera

John Pearn

Professor of Paediatrics & Child Health, and Consultant to Queensland Poisons Information Centre, and Consultant to Poisindex (International).
c/- Department of Paediatrics & Child Health
Royal Children's Hospital
Brisbane Old 4029.

Chronic fatigue syndrome comprises a most significant contemporary issue in public health. Clinically, the syndrome is due to any one of a number of known causes, and a significant proportion of unknown causes. Because of the highly subjective nature of the incapacitating symptoms, models do not exist. In this context, the search for and delineation of human intoxications, with syndromes identical to those of the chronic fatigue syndrome, are important in and understanding of both the aetiology and the natural history of this group of diseases.

Chronic ciguatera is produced by one of the most potent mammalian toxins known, ciguatoxin, which affects sodium channel function at the cellular level. The dramatic nature of acute ciguatera, its devastating longterm effects in perhaps five percent of sufferers and the peculiar syndrome of lowdosage re-challenge, all suggest that the toxin permanently destroys the molecular receptors on the sodium channels to which the toxin becomes affixed. This phenomenon, in turn, has raised questions about the role of channelopathies in other diseases which cause syndromes identical to those of the chronic fatigue syndrome.

Chronic ciguatera is thus a model not only for the chronic fatigue syndrome itself but opens the way to further study of the aetiology of other (in many cases, unknown) causes of the syndrome; and ultimately may lead the way to trials of drug therapy.