[The hyperventilation syndrome].

Acute hyperventilation (HV) rarely poses diagnostic or therapeutic problems. Chronic hyperventilation, however, with vague and multiple symptomatology due to respiratory alkalosis and increased breathing work, is often overlooked or misinterpreted, though it is a very common disorder of the general patient population. Chronic HV is frequently associated with emotional disturbances such as anxiety, panic and depression, or with psychosomatic disorders such as irritable bowel, effort syndrome and chronic pain. The diagnosis of chronic HV relies primarily on taking of a thorough history and is confirmed by an HV provocation test and arterial or cutaneous measurements of pCO2. Therapeutic measurements include psychotherapy, psychoactive drugs (antidepressants and benzodiazepines), beta-blockers and modification of abnormal breathing patterns.