Clinical characteristics and prognosis of neuralgic amyotrophy of the brachial plexus: A retrospective study in the Thai population

Background & Objective: Neuralgic amyotrophy, or Parsonage-Turner syndrome, is an underrecognized brachial plexopathy characterized by acute shoulder pain followed by weakness and atrophy. Limited data exist on its clinical spectrum in Thailand. The objective of this study is to describe the clinical features, electrophysiological and MRI findings, and disease course of neuralgic amyotrophy in a Thai cohort. Methods: We retrospectively reviewed 27 adult patients diagnosed with neuralgic amyotrophy of brachial plexus at the Neurological Institute of Thailand (2017–2024). Data included clinical presentation, nerve conduction studies, MRI findings, Medical Research Council (MRC) strength scores, and Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) functional outcomes. Results: The median patient age was 54 years; most were male. All presented with acute pain followed by focal weakness and atrophy, most often affecting shoulder abduction, external rotation, and elbow flexion. Triggers were identified in 25.9%, most commonly post-vaccination. Upper trunk involvement predominated. Radial nerve motor amplitudes were reduced in 51.9%, but sensory abnormalities were infrequent (18.5%). MRI showed T2 hyperintensity in 72.7% and gadolinium enhancement in 40.9%. Corticosteroids were administered to 74% of patients. Early treatment (≤30 days) was associated with significantly better QuickDASH (p = 0.0284) and MRC (p = 0.0172) scores. Most patients achieved meaningful recovery within 6 months, with peak motor improvement at second follow-up. Conclusion: This study details clinical and MRI features of neuralgic amyotrophy in Thai patients, emphasizing early diagnosis and corticosteroid treatment to improve functional outcomes.