An 80-year-old woman presented to the emergency department with sudden-onset bilateral horizontal diplopia accompanied by left-sided upper eyelid ptosis. On further questioning, she reported a 1-week history of drooling when eating. She had no other associated neurological or constitutional symptoms. No anhidrosis was noted. Her medical history was significant for a 2-year history of constant, dull, left-sided facial pain diagnosed as trigeminal neuralgia by her treating neurologist and moderately improved with gabapentin and nortriptyline. Recent computed tomography (CT) of the brain, conducted as part of her headache workup, had been reported as normal.