Neuralgic amyotrophy and Covid 19 infection: 2 cases of spinal accessory nerve palsy

Coll, Clemence; Tessier, Muriel; Vandendries, Christophe; Seror, Paul

Objective Neuralgic amyotrophy (NA), also known as Parsonage Turner Syndrome is often triggered by mechanical stress or upper respiratory tract viral infections. We reported 2 cases of shoulder weakness and amyotrophy related to spinal accessory nerve (SAN) palsy due to neuralgic amyotrophy occurring after COVID-19 infection. Methods For both patients, clinical history, clinical examination, electrodiagnostic (EDX), and imaging examinations invalidated other diagnoses but confirmed NA diagnosis. Results The NA involved only the SAN in both cases. EDX revealed a characteristic axonal lesion found in NA. SAN conduction study revealed normal latencies and low compound motor action potential amplitude for trapezius muscle when needle examination demonstrated a neurogenic pattern and denervation signs in the trapezius muscle. Both patient's MRI revealed denervation T2 hyper signal in impaired muscles, and hyper signal of the involved roots, trunks, or nerves without any mass, cyst, injury, fibrous band, or tearing signs along SAN course. Conclusions The Covid-19 infection could be the trigger for NA as many other viruses, and as it is a possible trigger for Guillain Barré Syndrome.