Beneficial effect of plasmapheresis but not on IVIG in Bickerstaff's brainstem encephalitis
Four weeks after a severe pneumonia of unknown etiology, a 71 year-old woman developed progressive diplopia, gait ataxia and slurred speech over two days. Neurological examination revealed almost complete ophthalmoplegia, limb ataxia, severe dysarthria to anarthria, central tetraparesis mainly affecting the right hemiside with right sided extensor plantar response and drowsiness. Nerve conduction studies of the limbs including F-wave responses were normal. CSF analysis demonstrated a slight lymphocytic pleocytosis of 8/µl and was otherwise normal. Routine blood tests, anti-hu, anti-ri were negative. Anti-GQ1b IgG antibodies were positive (40%, normal:<12%). Serology on HSV, VZV, vasculitis, and listeria-PCR were negative. MRI showed diffuse hyperintense lesions of the whole pons, the midbrain, and both thalami on T2-weighted images without Gd enhancement. Due to the preceding pneumonia and the presence of anti-GQ1b IgG antibodies Bickerstaff's brainstem encephalitis is the most probable diagnosis. IVIG treatment (0.4g/kg/d for 5 days) showed no effect and steroid treatment (1g/d prednisolone i.v. over 5 days) only slightly improved vigilance. However, plasmapheresis (7 courses within 14 days) was followed by a significant improvement. The patient was awake, her speech improved, ophthalmoplegia ameliorated to a slight upward gaze paresis, and the patient was mobilized. MRI follow-up 6 weeks later was almost unchanged. Bickerstaff's brainstem encephalitis is rare disease and no specific treatment regime has been established so far. We are aware of only two other case reports presenting serial MRIs.