Dyspnoea: underlying mechanisms and treatment

Abstract

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.

The Impact of Exercise-Induced Bronchoconstriction on Athletic Performance: A Systematic Review

“…As the brainstem or motor cortex provides efferent commands to the ventilatory muscles a copy of this command is sent to the sensory cortex. The exchange between the motor and sensory cortex is termed 'corollary discharge' and is thought to be the mechanism by which conscious perception of effort arises [43]. This exchange has been proposed to determine the severity of dyspnoea and perception of effort during exercise.…”

Diagnosis of asthma – a new approach

“…The respiratory center receives projections from a variety of receptors: central and peripheral chemoreceptors, receptors in the airways, chest joints, tendons, and respiratory muscles that affect ventilation and may cause dyspnea. The current theory of dyspnea is that it arises as a result of a mismatch between incoming signals from the receptors and outgoing signals from the respiratory center to the respiratory muscles (motor command) (33)(34)(35). When propagated to the sensory area of the cortex, the mismatch is felt as dyspnea of varying type and degree.…”

“…When propagated to the sensory area of the cortex, the mismatch is felt as dyspnea of varying type and degree. The qualitatively different types/sensations may be caused by different pathophysiological mechanisms (34)(35)(36)(37).…”

“…These sensations are caused by the activation of respiratory receptors. The bestdescribed dyspneic sensations are effort/work, tightness of the chest, and air hunger (35). A bronchoconstriction induced by, for example, inhaled histamine and methacholine may be felt as an increased effort/work (35,40).…”

“…The bestdescribed dyspneic sensations are effort/work, tightness of the chest, and air hunger (35). A bronchoconstriction induced by, for example, inhaled histamine and methacholine may be felt as an increased effort/work (35,40). Effort/work may also be triggered if the respiratory muscles are weakened or if they are strained, for example, when lung volumes are increased because of hyperinflation (34,(41)(42)(43).…”