Neuralgic amyotrophy is not the most common neurologic disorder of the shoulder: a 78-month prospective study of 60 neurologic shoulder patients in a specialist shoulder clinic.

Abstract

Neuralgic amyotrophy (NA) was first described in 1948. Traditional literature describes a painful attack with sudden onset, followed by paresis, with varied outcomes. Recent studies have suggested NA is currently underdiagnosed. However, a large number of studies detailing NA originate from a small group of sources. Our study compared the onset, diagnosis, investigation, and treatment of all neurologic shoulder conditions to provide comparable data for these studies. Data were collected from 60 patients (81.6% male; median age, 41.5 years) during a 78-month period. Patients with a diagnosis of a neurologic disorder of the shoulder with confirmatory electromyogram (EMG) studies were included. NA was diagnosed in 18 patients before the EMG investigation. Of the clinically diagnosed NA patients, only 5 (27.8%) had EMG findings supportive of NA. A further 5 patients with a clinical diagnosis other than NA were diagnosed with NA after EMG findings. Overall, 10 patients (16.6%) in our study were diagnosed with NA after EMG studies. Only 4 (40.0%) reported a sudden onset attack associated with NA. Supraspinatus and infraspinatus were involved in 9 patients (90.0%), suggesting a predictable distribution of muscle involvement. These results suggest that NA is overdiagnosed and does not warrant the increased attention suggested by recent articles. The current study also highlights a necessity to perform EMG investigations in all cases of suspected NA because the accuracy of the clinical assessment is poor.