1652 - Bilateral Phrenic Neuropathy in Neuralgic Amyotrophy: Rare, Clinically Significant, and Required Early and Careful Evaluation

Friday, February 20, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

JL

Junyao Li, BS

Medical Student
Northwestern Feinberg School of Medicine
Chicago, Illinois, United States

Co-Author(s)

BW

Briana Williams, BS

Medical Student
Northwestern University Feinberg School of Medicine
Chicago, Illinois, United States
ND

Nicholas Demetriou, MD

PGY1
Loyola University Medical Center
Maywood, Illinois, United States

Corresponding Author(s)

CF

Colin K. Franz, MD/PhD

Associate Professor
Shirley Ryan Ability Lab
Chicago, Illinois, United States

Submitter(s)

JL

Junyao Li, BS

Northwestern Feinberg School of Medicine
Chicago, Illinois, United States

Objectives: Neuralgic amyotrophy (NA) is an immune-mediated neuropathy that can involve the phrenic nerve and cause diaphragmatic paralysis. Bilateral phrenic involvement is rare, and data on presentation and recovery are limited. Our research aims to characterize the prevalence, clinical course, and outcomes of bilateral phrenic neuropathy in NA.

Design: We reviewed our clinical diaphragm dysfunction registry ( >200 patients), which includes individuals with high cervical spinal cord injury and phrenic neuropathies. Patients with NA were identified by clinical presentation, imaging, and electrodiagnostic confirmation. Demographics, pulmonary function tests (PFTs), ventilatory support, treatments, and follow-up outcomes were analyzed.

Results: Of 75 patients with NA and objective diaphragm involvement, 4 (5%) demonstrated bilateral phrenic neuropathy. All presented with acute orthopnea and exertional dyspnea, requiring non-invasive ventilation (CPAP or BiPAP). PFTs revealed severe reductions in vital capacity, particularly in the supine position. Treatments included corticosteroids, phrenic nerve electrical stimulation, and pulmonary-focused physical therapy. Over 1–3 years of follow-up, all patients showed gradual spirometry and symptomatic improvement, though none returned to baseline. Exertional limitations persisted in all cases. Notably, one additional patient initially classified as bilateral phrenic neuropathy was later re-diagnosed with amyotrophic lateral sclerosis based on progression of weakness to other muscle groups and was excluded from the analysis.

Conclusions: Bilateral phrenic neuropathy in NA is rare but clinically significant, affecting approximately 5% of NA patients with diaphragm involvement in our registry. Although recovery is often protracted, meaningful improvements in pulmonary function and symptoms can occur with conservative supportive care and rehabilitation. Compared to their unilateral counterpart, bilateral cases carried a higher vascular comorbidity burden and increased respiratory complication and warranted the need for heightened surveillance, early diagnosis with sensitive tools, and tailored rehabilitative strategy. Equally important is careful longitudinal evaluation to avoid misdiagnosis and to promptly identify alternative conditions such as amyotrophic lateral sclerosis.