Case Presentation: A 40-year-old male with no significant history presented with acute dizziness, visual disturbances, and gait abnormality, preceded by a viral prodrome. He reported headache, neck stiffness, vertical diplopia, and neurological exam revealed bilateral CN 6 palsy, left CN 3 palsy, restricted extraocular movements, and bilateral dysmetria. Cardiovascular, respiratory, and abdominal exams were unremarkable. He was admitted for evaluation and empirically treated for possible meningitis. Brain and spine imaging, including CT, CTA, and MRI, were unremarkable. CSF analysis showed WBC 359/mm³ (80% lymphocytes), protein 47 mg/dL, glucose 82 mg/dL, and negative microbiological tests. HIV was non-reactive, and anti-GQ1b antibodies were elevated at 192. Diagnosed with Bickerstaff brainstem encephalitis, he received IVIG for four days with significant improvement. Discharged to acute rehab, he showed progress but experienced mild residual dizziness and unsteadiness.
Discussion: In 1951, Edwin Bickerstaff described three cases of altered mental status, ophthalmoplegia, and ataxia, naming them “mesencephalitis and rhombencephalitis.” Later, he expanded the study and termed it “brainstem encephalitis,” now known as Bickerstaff Brainstem Encephalitis (BBE). Diagnostic criteria include progressive, symmetric external ophthalmoplegia and ataxia for four weeks, along with consciousness disturbance or hyperreflexia. BBE falls within the “Fisher-Bickerstaff syndrome” spectrum and shares features with Guillain-Barré Syndrome (GBS) and Miller-Fisher Syndrome (MFS), with anti-GQ1b antibodies often present.BBE is an autoimmune, demyelinating condition triggered by infections like Campylobacter jejuni, Mycoplasma pneumoniae, or SARS-CoV-2. Molecular mimicry likely causes immune-mediated brainstem inflammation and demyelination. The disease is rare, with unclear prevalence due to underreporting and diagnostic challenges. It often follows infections, and post-COVID-19 cases highlight viral triggers.Untreated BBE can cause severe complications, including permanent ataxia, ophthalmoplegia, and respiratory dysfunction. In our case, the timely administration of IVIG after confirming elevated anti-GQ1b antibodies led to a favorable outcome, highlighting the importance of early diagnosis and intervention.Ethical challenges include misdiagnosis, resource limitations for IVIG, and the absence of standardized treatment protocols, underscoring the need for further research and vigilance in clinical care.
Conclusions: This case highlights the diagnostic challenges and therapeutic response in Bickerstaff Brainstem Encephalitis (BBE), a rare and often under-recognized condition. Despite an initial misdiagnosis and empiric antibiotic therapy for suspected meningitis, the diagnosis of BBE was confirmed through elevated anti-GQ1b antibodies, leading to successful treatment with intravenous immunoglobulin (IVIG). This case underscores the importance of considering rare autoimmune conditions in the differential diagnosis of neurological symptoms, particularly following a viral prodrome. Early recognition and prompt treatment with IVIG are crucial for favorable outcomes, although residual symptoms may persist in some cases. Enhanced awareness of BBE among clinicians can facilitate timely diagnosis and intervention, ultimately improving patient prognosis.