Dyspnoea: underlying mechanisms and treatment.

Dyspnoea is the result of a complex interaction of physiological, psychosocial, social, and environmental factors. Although several sensory receptors located throughout the respiratory system are considered to be responsible for generation of dyspnoea, there is no afferent receptor solely responsible for the sensation of dyspnoea. Afferent information from the sensory receptors is processed at the cortex along with the respiratory motor command from the cortex and brainstem, and a mismatch between the motor command and the incoming afferent information may result in dyspnoea. Dyspnoea is not a single sensation and there are at least three distinct sensations including air hunger, work/effort, and chest tightness. Like pain, dyspnoea has at least two distinct separate dimensions, that is, a sensory and an affective dimension. Recent neuroimaging studies suggest that neural structures subserving pain and dyspnoea might be shared, and therefore the neurophysiological and psychophysical approaches used to understand pain can be applied to dyspnoea research. Although effective treatment of dyspnoea remains an elusive goal at the moment, a better understanding of the pathophysiology and neurophysiology of dyspnoea may provide a rationale for effective therapy of dyspnoea. In this context, treatment strategies in dyspnoea should be similar to those used in pain.