Table 2.

Diagnostic criteria for Bickerstaff’s brainstem encephalitis

“Defined” Bickerstaff’s brainstem encephalitis must meet the requirements of (1), (2), and (4).
“Probable” Bickerstaff’s brainstem encephalitis must meet the requirements of (1) and (4) or (2), (3), and (4).
(1) Acute progressive external ophthalmoplegia, † ataxia, and impaired conscious level by 4 weeks, followed by spontaneous recovery within 12 weeks after onset.
(2) Positive for serum IgG anti‐GQ1b antibodies.
(3) Incomplete agreement on (1) because of one or more of the following reasons:
–It is impossible to evaluate ataxia because of severe limb weakness or consciousness disturbance.
–Unconfirmed recovery of symptoms.
–Remarkable laterality of external ophthalmoplegia.
–Long tract sign (hemisensory disturbance, pyramidal sign, or spasticity) instead of impaired level of consciousness.
(4) Other conditions are excluded in laboratory and imaging tests. The excluded conditions are Wernicke’s encephalopathy, cerebrovascular disorder, multiple sclerosis, neuromyelitis optica, neuro‐Behçet disease, neuro‐Sweet disease, pituitary apoplexy, viral brainstem encephalitis, myasthenia gravis, brainstem tumor, vasculitis, botulism, Hashimoto encephalopathy.

Ig, immunoglobulin.

^†Lateral symmetry is the rule, but mild laterality is also permitted. Features other than the incomplete item(s) must meet (1).