Dyspnea as the Predominant Manifestation of Bilateral Phrenic Neuropathy

• Published in: Mayo Clinic proceedings Vol. 79; no. 12; pp. 1563 - 1565
• Main Authors: Kumar, Neeraj, Folger, W. Neath, Bolton, Charles F.
• Format: Journal Article
• Language: English
• Published: Rochester, MN Elsevier Inc 01.12.2004; Mayo Medical Ventures; Elsevier Limited
• Subjects: Biological and medical sciences; Brachial Plexus Neuritis - diagnosis; Diagnosis, Differential; Dyspnea - diagnosis; Electromyography; Female; Follow-Up Studies; General aspects; Humans; Male; Medical sciences; Middle Aged; Neural Conduction; Phrenic Nerve - physiopathology; Pneumology; Respiratory Function Tests; Respiratory Paralysis - diagnosis; Respiratory system : syndromes and miscellaneous diseases; Risk Assessment; Severity of Illness Index; FVC; EMG; PFT; Medicine; Bilateral; Nervous system diseases; Dyspnea; Neuropathy; Respiratory disease
• ISSN: 0025-6196; 1942-5546
• DOI: 10.4065/79.12.1563

Phrenic neuropathy associated with brachial neuritis has been well described; however, bilateral phrenic neuropathy with minimal or no involvement of the brachial plexus has not. We review the clinical features, as well as the results of radiographic studies, pulmonary function tests, and electrodiagnostic studies, of 3 patients in whom dyspnea was the presenting manifestation of bilateral phrenic neuropathy. All 3 patients had acuteonset dyspnea, which led to consideration of a pulmonary or cardiac etiology. Phrenic nerve conduction studies showed bilateral axonal degeneration of the phrenic nerves. Diaphragmatic paralysis should be considered in the differential diagnosis of acute-onset dyspnea. Dyspnea increases typically when the patient lies down, and paradoxical respiration may be present. Neck, shoulder, or upper limb pain may occur at onset. Inspiratory pressures may be reduced, but a comparison of the forced vital capacity when the patient is standing and supine is more specific for diaphragmatic weakness. Phrenic nerve conduction studies and diaphragmatic electromyography may provide evidence of bilateral involvement. Subclinical evidence of brachial plexus involvement may be present. The prognosis for patients with bilateral phrenic neuropathy may be more favorable than reported previously.