A right brachial plexopathy should be considered given the weakness of proximal as well as distal muscles of the right upper limb as well as changes in the sensory exam and and reflexes. In the left upper limb, the symptoms are more in the distribution of the ulnar nerve. This is suggestive for a multifocal sensory motor neuropathy affecting bilateral upper limbs. Scapular winging may represent neuropathy of long thoracic nerve and is often part of a brachial plexopathy.

Differential diagnosis includes bilateral idiopathic brachial plexopathy (Parsonage Turner Syndrome), mononeuropathy multiplex secondary to vasculitis, neoplastic infiltration (e.g. neurolymphomatosis), hereditary neuropathy with liability to pressure palsies (HNPP), and CIDP variant (predominantly involving upper limbs). Click here for nerve conduction study.