Expert Clinical Perspectives: Evaluation and management of dyspnea as the dominant presenting feature in neuromuscular disorders
Abstract:
Dyspnea is a common symptom in neuromuscular disorders and, although multifactorial, it is usually due to respiratory muscle involvement, associated musculoskeletal changes such as scoliosis or, in certain neuromuscular conditions, cardiomyopathy. Clinical history can elicit symptoms such as orthopnea, trepopnea, sleep disruption, dysphagia, weak cough, and difficulty with secretion clearance. The examination is essential to assist with the diagnosis of an underlying neurologic disorder and determine whether dyspnea is from a cardiac or pulmonary origin. Specific attention should be given to possible muscle loss, use of accessory muscles of breathing, difficulty with neck flexion/extension, presence of thoraco-abdominal paradox, conversational dyspnea, cardiac examination, and should include a detailed neurological examination directed at the suspected differential diagnosis. Pulmonary function testing including sitting and supine spirometry, measures of inspiratory and expiratory muscle strength, cough peak flow, sniff nasal inspiratory pressure, pulse oximetry, transcutaneous CO2, and arterial blood gases will help determine the extent of the respiratory muscle involvement, assess for hypercapnic or hypoxemic respiratory failure, and qualify the patient for noninvasive ventilation when appropriate. Additional testing includes dynamic imaging with sniff fluoroscopy or diaphragm ultrasound, and diaphragm electromyography. Polysomnography is indicated for sleep related symptoms that are not otherwise explained. Noninvasive ventilation alleviates dyspnea and nocturnal symptoms, improves quality of life, and prolongs survival. Therapy targeted at neuromuscular disorders may help control the disease or favorably modify its course. For patients who have difficulty with secretion clearance, support of expiratory function with mechanical insufflation-exsufflation, oscillatory devices can reduce the aspiration risk.
The objectives of this activity are to: 1) Be able to obtain a focused history from, and perform an appropriately-directed examination of, patients referred for possible neuromuscular causes of dyspnea; 2) Be able to order and interpret appropriate diagnostic examinations for patients with dyspnea of suspected neuromuscular origin; 3) Understand and implement basic management processes for patients with dyspnea of neuromuscular origin, including the use of respiratory muscle training and the initiation of noninvasive ventilation.
ACCREDITATION STATEMENTThe AANEM is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
DISCLOSURE INFORMATION
Drs. Mamarabadi, Mauney, and Aboussouan have no conflicts of interest to disclose. Dr. Yuebing Li has served as a consultant for Advisory Board Meeting by Alexion, Argenx, Catalyst, Immunovant, and UCB Pharma, and received grant support from Argenx. Conflicts have been resolved according to ACCME guidelines.
CREDIT DESIGNATION The AANEM is accredited by the American Council for Continuing Medical Education (ACCME) to providing continuing education for physicians. AANEM designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Credit expires 9/10/2027.
Mansoureh Mamarabadi MD; Sarah Mauney DO; Yuebing Li MD; Loutfi S. Aboussouan MD