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

Related articles:

• Approach to weakness, approach to sensory deficit, Brachial plexopathy,