Correlation of the Maximal Respiratory Pressures, Respiratory Airflow and Dysphagia in Patients with Acquired Autoimmune Myasthenia Gravis

Introduction: Patients with Acquired Autoimmune Myasthenia Gravis (AAMG) have a frequent complaint of muscle fatigue, resulting in respiratory distress, associated or not to the signs and symptoms of dysphagia. Objective: to characterize the measures of respiratory and appendicular muscle strength, expiratory and cough peak flow and relate to the degree of dysphagia in patients with AAMG. Methods: We assessed 20 patients with a diagnosis of Acquired autoimmune myasthenia gravis, being 14 (70%) female and 6 (30%) male, with an average age of 38.71 and 50.16 years, respectively. The following procedures were performed: speech and swallowing evaluation and respiratory clinical evaluation. It was incorporated measures of maximum inspiratory pressure, maximum expiratory pressure, peak expiratory flow and peak cough flow. Results: there was a statistically significant relationship between alteration of muscles of lips, tongue and buccinator and the severity of dysphagia. 70% of patients referred to dyspnoea, being that the averages of percentage of predicted of MEP and MIP, PFE were below 80% in patients with dysphagia. Significance was found in the correlation between measures of force and of respiratory airflow. Conclusion: the strength of cough expiratory flow is correlated to the inspiratory and expiratory muscle force. The involvement of the orofacial musculature and reduced values of MIP, MEP and PFE were indicators of the deterioration of oropharyngeal dysphagia. Both measures of respiratory muscle strength are lower than predicted.