Bradley Bierman, DO
Resident Physician
The Wright Center for GME
Scranton, Pennsylvania, United States
Abhinav Arora, DO
Resident Physician
The Wright Center
Scranton, Pennsylvania, United States
Bruce Zhang, MD
Attending Physician
Northeast Rehab
Scranton, Pennsylvania, United States
Acute Motor Axonal Neuropathy secondary to COVID-19
Case Description:
33-year-old woman presented with foot weakness in 2020 after COVID-19. Several weeks later, she developed right upper limb weakness. There were no sensory complaints. She was subsequently referred to Physiatry in May 2024. Examination revealed foot intrinsic atrophy, mild steppage gait, and impaired heel/toe walking. The right upper limb examination revealed 3/5 motor strength with shoulder abduction and elbow flexion. Electrodiagnostic testing of the lower extremities demonstrated diffuse, length-dependent axonal motor-only peripheral neuropathy of subacute progressing to chronic duration. There was ongoing active denervation with background reinnervation. The upper extremities demonstrated chronic right upper trunk plexopathy with substantially reduced motor recruitment without active denervation and sparing of sensory nerves. Findings and clinical history were deemed consistent with a patchy Acute Motor Axonal Neuropathy (AMAN). The patient was prescribed physical therapy but advised to hold resistance training in the lower limbs given active denervation. She was referred to neurology for IVIG.
Discussions:
Guillain-Barré Syndrome (GBS) is a set of acute immune-mediated peripheral polyneuropathies. GBS is divided into axonal and demyelinating subtypes. AMAN is a rare axonal variant of GBS that accounts for 5–10% of cases. On nerve conduction, AMAN is characterized by reduced amplitudes of compound motor action potentials without reduction in conduction velocity, with normal sensory nerve action potentials. Electromyography typically reveals denervation potentials. Treatment is plasma exchange (PLEX) or intravenous immunoglobulin (IVIG).
Conclusions:
This report serves to showcase the importance of history-taking and electrodiagnostic evaluation in managing patients with vague complaints of weakness. It secondarily serves to bring awareness to the incidence of GBS-like variants in the post-COVID-19 era. AMAN is a considerably rare subtype of GBS. Appropriate diagnosis expedited the rehabilitation plan and tertiary referrals for the patient.
