DaCosta's syndrome: chronic symptomatic hyperventilation.

In 1871, DaCosta published his observation of somatic symptoms preceded by significant hyperventilation. More than a century later, the hyperventilation syndrome remains a poorly defined but common clinical condition. Although familiar to most practitioners of medicine when it presents as an acute phenomenon, the diagnosis may go unrecognized in its chronic form. The ability of a chronic hyperventilatory state to mimic a life-threatening cardiopulmonary disease is not always appreciated.