Axonal excitability findings in acute inflammatory demyelinating polyneuropathy related to SARS-CoV-2

Guillain–Barré syndrome (GBS) is a disorder of the peripheral nervous system characterized by acute-onset ascendance paresis. We present a patient who was diagnosed as having facial-onset acute inflammatory demyelinating polyneuropathy after being infected with SARS-CoV-2. A 51-year-old man presented to the emergency department with facial diplegia. He then developed bilateral ascendance paralysis. He had noticed that for 1 month, he had smell and taste disturbances. SARS-CoV-2 infection was suspected. Nasopharyngeal swab polymerase chain reaction test was negative, but anti-SARS-CoV-2 antibody was found to be positive. A nerve conduction study showed prolonged motor distal and F wave latencies with decreased motor and sensory compound muscle action potential amplitudes. Lumbar puncture revealed albuminocytologic dissociation. According to the neurologic examination and laboratory findings, the patient was diagnosed as having acute inflammatory demyelinating polyneuropathy. An axonal excitability study revealed fanning in pattern with prolonged refractoriness, which indicates nodal sodium channel disturbances. Facial-onset SARS-CoV-2–related GBS has been rarely reported; however, facial involvement seems to be one of the features of the neurologic findings.