W134 - Miller Fischer Syndrome as a Rare Mimic of Botulism

Abstract Text: Botulism presents with symmetric neurologic deficits including diplopia, facial weakness, and descending muscle weakness with normal mental status and absence of fever, but these symptoms overlap with a variety of conditions including immunologic neuropathies. We present the case of a 19-year-old male construction worker with no significant medical history who developed binocular diplopia, bilateral mydriasis, extremity weakness, and gait ataxia after eating poorly refrigerated sandwiches and daily exposure to roofing materials. On examination, he exhibited external ophthalmoplegia, symmetric extremity weakness, and normal reflexes in an otherwise afebrile and appropriate teenager.

Basic labs and inflammatory markers were unremarkable. He was treated with botulinum antitoxin without improvement. Respiratory panel was positive for rhinovirus. Head imaging was normal. Lumbar puncture revealed albuminocytologic dissociation concerning for a post-viral autoimmune condition. He was treated with IVIG with marked improvement and was discharged home without need for rehabilitation.

Send-out CSF studies were later positive for anti-GQ1b antibodies (387), Asialo-GM1 IgG/IgM antibodies (51), and an elevated cerebrospinal fluid IgG synthesis index consistent with Miller Fisher Syndrome (MFS), a rare variant of Guillain-Barré syndrome.

This case highlights the importance of considering immunologic causes in addition to infectious and toxic exposures in healthy patients with new neurologic deficits. Intravenous immunoglobulins may be a suitable treatment in many of these diseases.