Infections Associated with Bickerstaff Encephalitis
Mycoplasma pneumoniae is the most commonly identified infectious trigger of Bickerstaff brainstem encephalitis, characterized by progressive symmetrical external ophthalmoplegia and ataxia. 1
Common Infectious Triggers
- Respiratory tract infections are the most frequent preceding events, occurring in approximately 50% of Bickerstaff encephalitis cases 2
- Gastrointestinal infections are the second most common antecedent infections associated with Bickerstaff encephalitis 2
- Mycoplasma pneumoniae is specifically identified as a key infectious trigger, with characteristic progressive symmetrical external ophthalmoplegia and ataxia 1
- Influenza viruses (particularly influenza A and B) have been documented as triggers for Bickerstaff encephalitis 1
- Haemophilus influenzae has been identified as a probable trigger in some cases 3
Less Common Infectious Triggers
- Enterovirus infections, particularly enterovirus 71, can trigger brainstem encephalitis syndromes 1
- Epstein-Barr virus has been associated with development of autoimmune encephalitis including Bickerstaff variants 1
- Varicella zoster virus has been linked to autoimmune encephalitis development 1
- Orientia tsutsugamushi (causative agent of scrub typhus) has been reported as a rare trigger 4
- SARS-CoV-2 (COVID-19) has been temporally associated with Bickerstaff encephalitis, though causality remains under investigation 5
Pathophysiological Mechanism
- Bickerstaff encephalitis is considered an autoimmune disease triggered by preceding infections 2
- The pathophysiology involves molecular mimicry, where antibodies produced against infectious agents cross-react with neural tissues 1
- Anti-GQ1b and anti-GM1 ganglioside antibodies are frequently detected in patients with Bickerstaff encephalitis 2, 6
- The similarity between bacterial glycolipids and human myelin glycolipids leads to aberrant immune activation against self-antigens 5
- Bickerstaff encephalitis exists on a spectrum with Guillain-Barré syndrome and Miller-Fisher syndrome as post-infectious demyelinating diseases 6
Clinical Presentation
- The classic triad includes external ophthalmoplegia, ataxia, and altered consciousness 2, 6
- Initial symptoms often include consciousness disturbance, headache, vomiting, diplopia, gait disturbance, dysarthria, and fever 2
- Rapid progression is typical, with a median of 2 days from symptom onset to hospitalization 1
- Intensive care is frequently required (55% of cases) due to rapid progression 1
- Overlapping features with Guillain-Barré syndrome may occur, suggesting combined central and peripheral nervous system involvement 6
Diagnostic Considerations
- Diagnosis is based on clinical findings, cerebrospinal fluid analysis, electroencephalography, electromyography, and magnetic resonance imaging 2
- Anti-GQ1b antibodies are detected in more than half of patients 2
- Anti-GM1 antibodies are detected in approximately 40% of patients 2
- Cerebrospinal fluid may show pleocytosis or cytoalbuminological dissociation 2
- Brain MRI may show abnormalities, though findings are normal in approximately 75% of pediatric cases 6
Treatment and Prognosis
- Treatment typically includes intravenous immunoglobulin, steroids, or plasma exchange, alone or in combination 2
- Early immunotherapy is associated with better outcomes 5
- Prognosis is generally good, with approximately 70% of pediatric patients reporting no sequelae 2
- Recovery in childhood is typically faster than in adulthood 2
- Severe cases with rapid progression may require more aggressive immunomodulatory treatment 3
Understanding the infectious triggers of Bickerstaff encephalitis is crucial for early diagnosis and prompt initiation of appropriate treatment, which can significantly impact patient outcomes.