A 70-year-old man presented in late summer with rapidly progressive weakness and respiratory failure. He was in his usual state of health until 1 week prior to presentation, when he developed malaise, headache, and fevers, followed by right leg weakness, prompting admission to a local hospital. Over the next 3 days, his weakness progressed to involve his right arm, then his extraocular, facial, and bulbar muscles, followed by his left arm and leg. On the fourth day of hospitalization (2 weeks after the onset of constitutional symptoms), he was intubated due to an inability to clear oral secretions and was transferred to our institution.Upon arrival, the patient had a temperature of 102.3°, intact mental status, normal pupillary responses, restricted horizontal and vertical gaze, downbeating nystagmus on downward gaze, weakness of his bilateral upper and lower facial muscles, and reduced muscle tone. He had 0/5 strength in all extremities, save trace left finger movement, intact sensation without a sensory level, trace reflexes, and absent Babinski signs.