Guillain-Barre syndrome is typically an ascending predominantly motor polyradiculoneuropathy, rarely presenting in fulminant form with extreme neurological deterioration, and need for mechanical ventilation, prolonged complex ICU management. Principally it can be viral , or autoimmune in origin, with diverse mechanisms of usually reversible nerve injury. Our case report describes a form, AIDP in association with acute cytomegalovirus infection with high blood viral and respiratory DNA CMV load, requiring antiviral therapy, highly activated and dominant CD3+CD8+ T cell response, negative autoantibody panel, suggesting a cytopathic etiology of nerve damage. We also report severe sympathetic dysautonomia presenting with tachycardia and hypertension. We emphasize the need to further enhance technologies enabling dissecting the many faces of GBS clinically.