Editor’s Comment: This study used the CDC “Fukuda” criteria to establish the two CFS cohorts. Although the Fukuda criteria do not require post-exertional malaise, the researchers found a positive correlation between shortness of breath (dyspnea), and “Exertional Exhaustion.” There was also a high occurrence of fibromyalgia (42% and 47%) in the two CFS groups. In the full study the authors suggest that the sensations of dyspnea, including lightheadedness and chest pain, may be due to central nervous system dysregulation, specifically, dysautonomia.
Dyspnea in Chronic Fatigue Syndrome (CFS): Comparison of Two Prospective Cross-sectional Studies
~Source: Global Journal of Health Science; Vol. 5, No. 2; 2013
By Murugan Ravindran et al.
Background: Chronic Fatigue Syndrome (CFS) subjects have many systemic complaints including shortness of breath. Dyspnea was compared in two CFS and control cohorts to characterize potential pathophysiological mechanisms.
Methods: Cohort 1 of 257 CFS and 456 control subjects were compared using the Medical Research Council chronic Dyspnea Scale (MRC Score; range 0–5). Cohort 2 of 106 CFS and 90 controls answered a Dyspnea Severity Score (range 0–20) adapted from the MRC Score. Subsets of both cohorts completed CFS Severity Scores, fatigue, quality of life, and systemic complaints questionnaires. Cohort 2 also responded to other Dyspnea, affective and anxiety instruments. A subset had pulmonary function and total lung capacity (TLC) measurements.
Results: MRC Scores were equivalent for females and males in Cohort 1 CFS (1.92 [1.72-2.16]; mean [95% confidence interval]) and controls (0.31 [0.23-0.39]; P < 0.0001 by 2-tailed, unpaired Student's t tests with Bonferroni corrections). Receiver-operator curves identified 2 as the threshold for positive MRC Scores in Cohort 1. This indicated 54% of CFS, but only 3% of controls, had significant Dyspnea. In Cohort 2, the threshold Dyspnea Severity Score of 4 indicated shortness of breath in 67% of CFS and 23% of these controls. Cohort 2 Dyspnea Scores were higher for CFS (7.80 [6.60-9.00]) than controls (2.40 [1.60-3.20]; P < 0.0001). CFS had significantly worse fatigue, other CFS defining criteria and quality of life compared to controls. Although CFS had worse depressive affect and anxiety scores, only the controls showed correlations with Dyspnea Score. Pulmonary function was normal in CFS, but Borg scores and sensations of chest pain and dizziness were significantly greater during testing than controls. TLC was normal except for 2 of 16 CFS who had hyperinflation. A general linear model of Cohort 2 CFS responses linked Dyspnea Scores with rapid heart rate, chest pain and dizziness.
Conclusions: Sensory hypersensitivity without airflow limitation contributed to Dyspnea in CFS. Correlates of Dyspnea in controls were distinct from CFS suggesting different mechanisms.
Source: Global Journal of Health Science; Vol. 5, No. 2; 2013. Murugan Ravindran, Oluwatoyin Adewuyi, Yin Zheng, Uyenphuong Le, Christian Timbol, Samantha Merck, Rania Esteitie, Michelle Cooney, Charles Read, James Baraniuk. Georgetown University, Washington DC, USA
The full article can be accessed HERE.