The causes are multiple:
• Infectious (enterovirus, adenoviruses, borreliosis…) ;
• Autoimmune (anti-MOG, anti-AQP4…) ;
• Systemic diseases (Behcet’s disease, sarcoidosis…) ;
• Metabolic diseases (mitochondriopathy…) ;
• Tumor.

It is brainstem damage which results in signs that can manifest as: ptosis (drooping eyelid), facial paralysis (asymmetry of the face), double vision (damage of muscles that mobilize the eye), swallowing disorders, breathing disorders, heart rate, blood pressure or alertness/consciousness disorder, drowsiness.

Brain MRI may show abnormalities in the brainstem that are isolated or associated with brain lesions.

Evolution is variable and depends on the cause.

Treatment of the cause.

Surveillance is mostly clinical.