Brachial Neuritis Workup

Updated: Jan 18, 2017
  • Author: Nigel L Ashworth, MBChB, MSc, FRCPC; Chief Editor: Milton J Klein, DO, MBA  more...
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Laboratory Studies

See the list below:

  • Usually within the reference range
  • Only indicated if systemic disease is suspected on clinical grounds
  • Complete blood count (CBC) and erythrocyte sedimentation rate (ESR) as nonspecific indicators of systemic disease
  • Antinuclear antibody (ANA) as a marker for connective-tissue disease
  • Human immunodeficiency virus (HIV) serology

Imaging Studies

Magnetic resonance imaging (MRI) or computed tomography (CT) myelogram scanning should be considered initially to rule out cervical radiculopathy (particularly C5/C6). MRI of the brachial plexus can help to rule out carcinomatous or granulomatous infiltration, if clinically indicated. [26, 27] Some of the newer MRI techniques, especially high-resolution MR neurography, can show abnormalities in the proximal root/plexus that may not be apparent with other investigations. [28]

A study by Lieba-Samal et al indicated that MRI and high-resolution ultrasonography (HRUS) can be useful in diagnosing brachial neuritis, with all clinically affected nerves/trunks of the study’s six brachial neuritis patients revealing segmental swelling on HRUS. In the five patients who underwent MRI, all clinically affected nerves displayed T2-weighted hyperintensity. [29]

A shoulder radiograph may be indicated to rule out specific shoulder pathologies. A chest radiograph is not usually part of the initial workup; however, it can be useful to rule out sarcoidosis or other granulomatous disease, as well as Pancoast tumor.


Other Tests

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  • Electrodiagnosis [4, 30, 31, 32, 33]
    • Electrodiagnosis should be considered initially to confirm neuropathic diagnosis and to rule out various other conditions (eg, radiculopathy, neuropathy, amyotrophic lateral sclerosis).
    • Specific localization can be made to various nerves.
    • Loss of sensory and motor amplitudes with relatively normal conduction velocity is frequent. Note, however, that this finding only begins to fall beyond the reference range after approximately 1 week.
    • Somatosensory evoked responses are not reliable for distinguishing radiculopathy from brachial plexus neuropathy, and F-waves are generally less helpful than routine conduction studies in localization.
    • Needle electromyogram (EMG) shows denervation (fibrillations, positive sharp waves, and/or motor unit potential changes) in affected muscles 2-3 weeks after onset; however, clinically uninvolved muscles also may show abnormalities. Approximately 50% of patients with unilateral clinical involvement demonstrate bilateral EMG abnormalities. EMG results for the paraspinal muscles usually are within the reference range. Electromyographic exclusion of a radiculopathy may be challenging. In addition, strict anatomic localization often is difficult.
    • Proximal conduction block has been reported in brachial neuritis; however, this finding should suggest focal forms of inflammatory demyelinating diseases. Proximal slowing also may occur from loss of large fibers, regenerating fibers, and/or segmental demyelination.


See the list below:

  • Nerve biopsy usually is not indicated in brachial neuritis. Axonal loss rarely is identified with biopsies of the radial sensory branch.
  • Lumbar puncture usually is not indicated. Analysis of cerebrospinal fluid generally is within the reference range in individuals with brachial neuritis.