A 20 year-old woman with no significant past medical history presents with lower back pain, and bilateral foot and hand tingling. Her symptoms rapidly progress over 4 days to include lower extremity weakness to the point that she is unable to mobilize her lower extremities. She reports coryzal symptoms 2 weeks ago. On examination, she has 0/5 power in her lower extremity with areflexia, but despite the paresthesias, she does not have sensory deficits. Laboratory analysis indicates elevated aminotransferases and mildly elevated protein in the CSF, with no cells and normal glucose. What is the most likely diagnosis?