Respiratory function and dyspnea in fibromyalgia syndrome

Objectives: To evaluate the presence of dyspnea and its association with the pulmonary function test or any other clinical parameters in patients with fibromyalgia syndrome [FMS]. Methods: Thirty-five females satisfying the American College of Rheumatology criteria for FMS and 20 healthy controls were included in this study. A history of dyspnea was obtained and classified into five grades according to the World Health Organization's [WHO] dyspnea classification. Spirometric pulmonary functions were measured in each subject including forced vital capacity, forced expiratory volume in one second, peak and forced expiratory and inspiratory flow, and maximum voluntary ventilation. Results: patients with FMS and controls did not differ in age and body mass index. Dyspnea was the fifth most common associated symptom and found in 57.1% of the patients. Spirometric values were normal among patients and controls, and the differences in pulmonary functions between patients and controls were not statistically significant [P > 0.05]. There was a statistically significant positive correlation between pain score measured by visual analog scale and the WHO dyspnea grade [R = 0.532, P < 0.001]. The WHO dyspnea grade was also found to be correlated positively with chest pain [R = 0.464, P < 0.005]. Conclusions: Dyspnea is a common symptom in patients with FMS and is not explained by pulmonary causes, but may partly be due to chest wall discomfort and pain intensity. Understanding the cause of this symptom in FMS may help in the management of these patients who are suffering from dyspnea.