Acute myelopathy with normal imaging.

A 17-year-old girl presented with rapidly progressive quadriparesis and ventilatory failure. The clinical findings indicated a spinal level, but the diagnosis of myelopathy was not supported by her initial spinal imaging and cerebrospinal fluid studies. She had completed treatment for Guillain-Barré syndrome before a follow-up spinal imaging study showed interval expansion and enhancement of the cervical cord.