Severe shoulder girdle pain
Weakness, paresthesias, and sensory losses that depend on which nerves are involved
Muscle atrophy may develop after several weeks of neuropathy
Loss of reflexes
Scapular winging
Parsonage-Turner syndrome
Idiopathic
Down syndrome
Post-infectious
Kounis syndrome
Viral
Sheehan's syndrome
Epstein-Barr, CMV, influenza, parvovirus, coxsackie, HIV, Polio