Brachial plexitis MRI

MR Neurography of Brachial Plexus

Clinically :  middle-aged male with left arm pain and weakness of sudden onset. No history of trauma. No history of radiotherapy.

MR Neurography of brachial plexus show diffuse enlargement with abnormal T2 hyperintensity iinvolving left brachial plexus nerves. Mild enlarged bilateral deep cervical group of lymph nodes.

Imaging diagnosis: Left side brachial plexitis.

Brachial plexitis

An inflammatory change involving the brachial plexus commonly seen in men between 30 to 70 years of age and is bilateral in 10-30% of patients .

Etiology:
• post radiation plexitis: usually presents 5-30 months after treatment.
• viral brachial plexitis, e.g. cytomegalovirus, Coxsackie, herpes zoster, Epstein-Barr virus, parvovirus B19
• immune-mediated
• toxic (related to previous serum, vaccine, antibiotic or other drug administration, human immunodeficiency virus serology)
• recent surgery
• anesthesia
• Lyme disease
• heredofamilial hypertrophic neuropathies like Charcot-Marie-Tooth disease, Dejerine-Sottas disease, chronic inflammatory demyelinating polyneuropathy.
• idiopathic ; Parsonage-Turner syndrome.

Diagnostic clues on MR Neurography are diffuse enlargement of nerves of brachial plexus with abnormal T2 hyperintensity and enhancement on post contrast MRI.