Brachial Neuritis
Condition of uncertain aetiology presenting with pain in the distribution of the affected nerves. Most commonly affects C5 and C6 of the brachial plexus resulting in denervation oedema of the supraspinatus and infraspinatus predominantly.
Key Clinical Features
Occasionally MR imaging can demonstrate enlarged nerves with increased signal but imaging findings within the nerves themselves are uncommon. Generally self-limiting but residual muscle deficits can be evident.
The condition as it affects the shoulder is called Parsonage Turner syndrome. This acute brachial plexus neuritis typically presents with severe shoulder pain followed by weakness and muscle atrophy.
Imaging Characteristics
- Denervation changes in affected muscles (typically supraspinatus and infraspinatus)
- T2 hyperintensity and muscle edema in acute phase
- Fatty infiltration and atrophy in chronic cases
- Nerve enlargement may be visible but is uncommon