The concomitant assessment of pain and dyspnea in acute exacerbations of chronic obstructive pulmonary disease; is pain an understudied factor?

Dyspnea is a prominent symptom of Chronic Obstructive Pulmonary Disease (COPD), occurring as a result of expiratory flow limitation, which may lead to varying degrees of dynamic hyperinflation, hypoxemia, hypercapnia and neuromechanical dissociation. Although pain appears to be a prevalent symptom in COPD patients, it is rarely considered in clinical practice guidelines for the management of the disease, which could be due to pain being a complex and understudied factor in COPD. When compared to other disease entities (diabetes, heart disease and arthritis), COPD patients had an increased risk of pain prevalence and intensity, second only to those with arthritis. There are several underlying mechanisms that may contribute to higher pain prevalence in COPD compared to healthy individuals. These include increased and persistent respiratory muscle loading, along with systemic inflammation, musculoskeletal disorders and co-morbities. In patients with stable COPD, pain is a prevalent symptom which negatively impacts quality of life, and is associated with higher levels of lung hyperinflation and dyspnea. An acute exacerbation of COPD (AECOPD) occurs when there is an acute worsening of respiratory symptoms requiring additional treatment. Thus, given the relationship between the two perceptions, many factors linked to pain in the stable state tend to worsen during an AECOPD. The systematic review by Clarke et al. focused on the prevalence of pain and dyspnea experienced concurrently in people admitted to hospital with an AECOPD. A total of 1300 articles were identified from initial database searches, however only four studies met the inclusion criteria and were included in the review. Pain and dyspnea are both unpleasant sensations which share many clinical, physiological and psychological features. Brain imaging studies highlight that perceptions of pain and dyspnea activate similar cortical regions of the brain, and share common neural mechanisms. Due to these commonalities, the review aimed to further understand the interactions between pain and dyspnea, and their clinical implications during an AECOPD. Of the available data, pooled prevalence of pain and dyspnea was 44% and 91% respectively, demonstrating that both symptoms are prevalent in COPD patients during acute exacerbations. However, due to the small number of studies co-reporting pain and dyspnea, the scope of the review to draw clinical associations and implications of both symptoms during AECOPD was limited. As described by the authors in the review, management of COPD exacerbations primarily focuses on relieving dyspnea, reducing medication and oxygen requirements, returning to baseline function and follow up care. Discharge care bundles have been shown to reduce hospital readmissions following hospitalisation for an AECOPD, but did not improve survival or quality of life. The individual components of discharge bundles tend to vary and it is not clear whether pain is considered within the education and self-management plans. This is likely due to pain during exacerbations being under recognised and under researched, as highlighted by Clarke et al., limiting the