Abnormal Respiratory Control in Acquired Dysautonomia

In a patient with acquired dysautonomia respiratory as well as circulatory control mechanisms were abnormal. In response to breathing of 10 per cent oxygen in nitrogen there was no respiratory drive, and at the same time the arterial-blood pressure fell, indicating the absence or failure of peripheral chemoreceptor function. Abnormal blood-pressure responses to tilting and Valsalva maneuvers showed a lack of sympathetic vasoconstriction, whereas the pupillary and cardiac responses to methacholine and atropine indicated parasympathetic nervous-system impairment. The ventilatory response to carbon dioxide was weak — a fact that may or may not mean central chemoreceptor involvement. The normal rapid breathing response at the onset of exercise developed in spite of the lack of sympathetic nervous and peripheral chemoreceptor functions.