Impaired Perception of Dyspnea in Patients with Severe Asthma

Abstract

Poor dyspnea perception might be a risk factor for developing asthma exacerbations. We investigated whether severe asthmatics with recurrent exacerbations (brittle asthma) have different dyspnea perception and sputum cells compared with equally severe, but stable asthmatics, or patients with mild steroid-naive asthma. Fifteen brittle asthmatics (13 female, median age 28 yr [range, 20 to 47 yr]), 15 matched severe-stable asthmatics (14 female, median age 26 yr [range, 17 to 52 yr]), and 11 mild asthmatics (8 female, median age 25 yr [range, 19 to 43 yr]) underwent inhalation tests with methacholine (MCh), and hypertonic saline combined with sputum induction. Dyspnea was assessed by Borg and Visual Analogue Scale (VAS), plotted against the percent fall in FEV1, and expressed as the slope of the regression line (Slope-Borg and Slope-VAS). The brittle and stable asthmatics had poorer perception than patients with mild asthma (Slope-Borg [p = 0.036], Slope-VAS [p < 0.001] for MCh). In patients with brittle asthma the perception was less as compared with severe-stable asthma (Slope-Borg for MCh: p = 0.05). In the severe asthmatics there was an inverse correlation between sputum eosinophilia and Slope-Borg and Slope-VAS (R = -0.55, p = 0. 002 and R = -0.37, p = 0.049), whereas this correlation was a positive one in the mild asthmatics (R = 0.79, p = 0.012 and R = 0. 67, p = 0.05). In conclusion, patients with severe asthma, particularly those with recurrent exacerbations, have blunted perception of dyspnea, which is related to the degree of sputum eosinophilia. This suggests that increased sputum eosinophilia is an indicator of clinical instabililty, and that eosinophilic airways inflammation might affect dyspnea perception in severe asthma.

Dyspnoea perception during clinical remission of atopic asthma

“…Indeed, there is a weak correlation between symptoms on the one hand and bronchial hyperresponsiveness and airways inflammation on the other. Several investigators have highlighted the possibility of diminished perception of dyspnoea in subjects with more severe grades of asthma, potentially leading to undertreatment in these subjects [7][8][9]. Such an inverse relationship is not a consistent finding [10].…”

“…The relationship between dyspnoea perception and other indices of asthmatic severity, such as the degree of bronchoconstriction, is poor [5,6]. Conversely, impaired dyspnoea perception is especially believed to play a role in severe asthma [7][8][9]. Poor perception of airflow obstruction may lead to undertreatment of asthma [10].…”

Descriptors and Perception of Dyspnea in African-American Asthmatics

“…African-American participants' comments indicated passivity regarding symptoms due to acclimatization to an inability to inhale, chest tightness, weakness, or dyspnea. It is believed that patients with more severe asthma underestimate the severity of their disease because of a blunted perception of dyspnea (15)(16)(17), and many African-Americans in our focus groups were unable to detect or describe when their asthma was worsening. This is particularly worrisome given the highly educated nature of our participants, suggesting that many patients with asthma are not properly taught by their physician about the nature and symptoms of their disease.…”

Poor perception of dyspnoea in children with undiagnosed asthma

“…Furthermore, the bronchial hyperreactivity tests were performed by experienced lung function assistants, who also had experience with Borg and VAS scores in children. In adults (median age 25 yrs), VEEN et al [27] found a slope of 0.06 for the Borg/FEV1 correlation in adults with brittle asthma and a Borg slope of 0.11 in stable asthma. Thus, the same small differences observed in the present study are found in adult patients with a clinically different asthma presentation.…”