Neuroradiologic and Neurophysiologic Findings of Neuralgic Amyotrophy

Abstract

Objective : Neuralgic amyotrophy (NA) is a distinct clinical syndrome that is characterized by the acute onset of shoulder and arm pain, weakness, and sensory loss. The purpose of this study was to assess the clinical characteristics of NA and to determine appropriate diagnostic modalities. Methods : We reviewed the medical and radiologic records of 10 patients diagnosed with NA retrospectively. Neurophysiologic studies were performed in all patients and magnetic resonance neurography was performed in the last three patients. Results : A total of 10 patients were enrolled in our study. All patients had clinical findings compatible with NA. The most common clinical presentation was severe shoulder pain and weakness in seven patients (70%). Neurophysiologic study results were abnormal in all patients. Brachial plexus magnetic resonance neurography showed that the affected brachial plexus showed a thickened and hyper-intense trunk. All patients were managed conservatively with analgesics and physical therapy. The pain and paralysis of all patients improved clinically within 6 months of the initiation of treatment. Conclusion : NA is a rare disease but the symptoms of NA can mimic those of other diseases. Neurophysiologic studies and magnetic resonance neurography are extremely useful tools for the diagnosis of NA. KEY WORDS :Neuralgic amyotrophy˙ Brachial plexus˙ Diagnosis˙ Neurophysiology˙ Magnetic resonance imaging.

MR neurography in Parsonage-Turner syndrome

“…This may be due to the fact that the patient has only mild neuritis so it cannot be detected by imaging or because the patient has been imaged too early when findings have not yet set-in or too late when the inflammation has subsided. [17212223242526] The affected muscles can show edema in the acute phase in which case they appear hyperintense in T2W images with maintained architecture. [17] Although edema can occur as early as within 2 days in an experimental set-up, it usually takes about 2 weeks to appear in an MR scan.…”

Neuralgic Amyotrophy Manifesting as Mimicking Posterior Interosseous Nerve Palsy

“…Though MRN is known for an early diagnostic method of NA 3 11) , MRN does not reveal an involvement of the trunk, but also C6 spinal nerve incompatible with clinical presentations. MRN has an advantage for diagnosing with NA in acute phase, when it is not appropriate to get a positive result by neurophysiologic study.…”

“…MRN has an advantage for diagnosing with NA in acute phase, when it is not appropriate to get a positive result by neurophysiologic study. However, this method does not always show all pathologic lesions of inflamed nerves because of the differences of their severity or technical error 11) .…”

“…In two-thirds of patients with NA, the upper trunk of the brachial plexus is most affected, but any part of peripheral nerve can be involved 9 10) . There are few reports of lower trunk involvement; Yu et al 11) reported three cases of lower trunk plexopathy in 10 patients with NA confirmed by neurophysiologic study, and their initial presentations on admission were ulnar nerve palsies after shoulder pain.…”

Spinal Cord Stimulation for Refractory Neuropathic Pain of Neuralgic Amyotrophy

“… 11 14 25) A hallmark of NA is a sudden, severe painful onset and the patch distribution of motor, sensory and autonomic symptoms. 17 27) Any part of the brachial plexus and the lumbosacral plexus can be involved, with any combination of motor and sensory impairment. 17 21) A bilateral involvement of the brachial plexus occurs in approximately 30% of patients; clinical features are commonly asymmetric in presentation.…”