Development of Lewis-Sumner Syndrome or Multifocal Acquired Demyelinating Sensory and Motor Neuropathy (MADSAM) Following COVID-19 Infection

Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), also known as asymmetrical or multifocal chronic inflammatory demyelinating polyneuropathy (CIDP) or Lewis-Sumner syndrome, is a painless asymmetric demyelinating sensorimotor mononeuropathy multiplex and is an atypical and rare variant of CIDP. We report a case of a 48-year-old female who presented with complaints of shortness of breath, fatigue, difficulty walking and speaking, and primarily right unilateral symptoms involving multiple peripheral nerves, the right phrenic nerve, and the facial nerve following a coronavirus disease 2019 (COVID-19) infection. She was diagnosed with MADSAM after an extensive physical examination, electromyography (EMG), nerve conduction tests, and laboratory testing. She improved following the initiation of long-term treatment with intravenous immunoglobulin (IVIG). To the best of our knowledge, this is the second reported case of MADSAM following a COVID-19 infection. There have been reports of demyelinating diseases of the central and peripheral nervous systems related to COVID-19; however, it remains unclear whether COVID-19 is the causative agent or only a correlative.