(765) An Immunological Plot Twist: Miller Fisher Syndrome Following Pneumococcal Vaccination

Introduction: Post-vaccination Guillain-Barré syndrome (GBS) has been commonly reported in medical literature, primarily linked to influenza vaccine subtypes. GBS following the pneumococcal vaccine (PV), however, is rarely reported with no studies demonstrating a clear association. This report details a case of Miller Fisher (MF) syndrome (a variant of GBS) after recent PV, encouraging further investigation into this connection.

Description: A 70-year-old female presented to the emergency room with headache, diplopia, and limb paresthesia, 8 days after receiving the PV. Initial neuroimaging showed white matter disease and segmental occlusion of the distal left vertebral artery with reconstitution. Lumbar puncture (LP) was performed, and cerebrospinal fluid showed elevated WBCs with neutrophil predominance, elevated protein and normal glucose. Additional autoimmune, inflammatory and paraneoplastic workup was sent while broad-spectrum antimicrobial treatment for suspected meningitis was initiated. She was subsequently intubated for worsening encephalopathy and hypoxic, hypercapnic respiratory failure and admitted to the Intensive Care Unit. MRI/MRV Brain was negative. EEG showed Delta-Theta coma. Serial neurological exams revealed coma with ocular square wave jerks. Repeat MRI Brain with and without contrast was suspicious for bilateral hippocampal enhancement thought to be possible brainstem or limbic encephalitis. LP was repeated with resolving pleocytosis, and subsequent exam showed purposeful vertical eye movements. Intravenous immunoglobulin was initiated and GM1 antibody test returned positive, confirming the suspicion of post-PV MF syndrome.

Discussion: GBS, and its rare MF variant, are autoimmune disorders proposed to involve antibodies attacking peripheral nerves. Adjuvant vaccinations may trigger autoimmunity by inducing antibodies that cross-react with myelin or axonal glycoprotein. Conjugated PVs enhance B-cell responses and potentially lead to autoimmune reactions like GBS. While serious reactions to PVs are rare and their association with GBS has been disputed, a United States Court of Federal Claims in March 2024 ruled in favor of a plaintiff who claimed his GBS resulted from PV, emphasizing the need to revisit this issue. Our case describes the first reported post-PV MF syndrome.