Synonyms:
a.k.a. Parsonage-Turner syndrome formerly brachial neuralgic amyotrophy
Diagnosis:
This is a clinical diagnosis supported by electrophysiological findings and consistent imaging
Clinical features:
Brachial distribution of pain followed in 3-10 days by weakness and atrophy with areflexia
In some cases sensory loss may occur
May be bilateral
Findings on investigations:
+EMG:
- Localised to brachial plexus, usually upper part,
- After onset of paresis: fibrillation potentials, positive waves in affected muscles. Spares paraspinal muscles (distinguishes this from radiculopathies)
- After recovery: giant polyphasic potentials
+NCS: Normal
MRI: T2 high signal in affected muscles
Investigations to consider:
LP with CSF analysis:
- Cytology
VZV PCR and serology
HIV testing
NCS/EMG
MRI brachial plexus: to help exclude malignancy
Treatment:
Analgesia
Physiotherapy +/-sling
Consider steroids