Hyperventilation Syndrome

MOST PHYSICIANS are quite familiar with the isolated attack of acute hyperventilation that is characterized by dramatic overbreathingand classically culminates in tetany. Although terrifying to the patient, and almost equally alarming to any onlooker, these attacks are usually brief and without serious medical sequelae. Recently we have come to recognize a chronic hyperventilation pattern that appears to be far more common, far more disabling but, paradoxically, less well known than the acute variety.5'6'7'8 This report will present an analysis of 250 patients with hyperventilation syndromes and will emphasize the clinical characteristics and course of this chronic hyperventilation pattern. As Table 1 indicates hyperventilation was psychogenic in origin in about 70 per cent of the patients in this series, with almost three times as many women as men falling in this category. There was an organic basis in only 2 per cent of the cases, usually infections and/or intoxications of the central nervous system.1'10 In the remaining 28 per cent, designated as "mixed," organic and psychological factors were jointly responsible. In these two latter groups the sexes were about equally involved. There are symptoms and signs referable to most body systems as a consequence of the diffuse biochemical and physiological changes resulting from overbreathing. The most prominent of the clinical features are listed in Table 2. Out of this welter of alarming bodily sensations the patients usually tend to focus on but a few, most often on symptoms referable to the cardiovascular or nervous system, and become exceedingly fearful that they are experiencing either a "heart attack" or a "stroke." An analysis of the chief or presenting complaints (see Table 1) reveals that over one half of the patients had concentrated on cardiovascular symptoms, and another one fifth on neurological symptoms, to the relative exclusion of the many other bodily changes that had occurred at the same time. Curiously, respiratory symptoms were not particularly prominent although changes in respiratory behavior were usually evident to any observer.