[Hyperventilation syndrome: current advances].

The hyperventilation syndrome has been described for half a century but clearly remains underdiagnosed. Its acute manifestation is easily diagnosed ("the tip of the iceberg") but its recognition in numerous subtle forms requires a particular degree of alertness on the part of the clinician ("the hidden part of the iceberg"). The incidence of this syndrome in the general population varies according to different authors as between 6-11% and may mimic diverse organic disorders. The physiological consequences of hyperventilation are reviewed as well as their contribution in the clinical picture. The aetiology of the syndrome and its links with organic pathology or psychiatric disturbances continues to be debated. Is hyperventilation the expression of abnormal respiratory function or a preferred manifestation of anxiety? This article discusses and reviews the variety of tests which enable the presumptive diagnosis to be confirmed. The response to the proposed treatments is generally excellent when one takes account of the numerous possible options. These include comportmental therapies such as respiratory re-education, the utilisation of betablockers and psychotrophic drugs or psychotherapy.