A case of acute flaccid myelitis caused by enterovirus D68 in which MRI was useful for diagnosis

Abstract

Acute flaccid myelitis (AFM) associated with an enterovirus-D68 (EV-D68) outbreak occurred in Japan in the fall of 2015.

We report the case of a 4-year-old boy with acute flaccid paralysis (AFP) predominant in the right upper limb following fever and gastrointestinal symptoms. Early MRI studies showed cervical spinal cord swelling and longitudinal hyperintensity cord lesion on T2-weighted sagittal images, and AFM was listed in the differential diagnosis. EV-D68 was detected in the nasopharynx, and AFM caused by EV-D68 was diagnosed based on the clinical symptoms, clinical course, and examination findings. Intravenous immunoglobulin and methylprednisolone pulse therapy were not effective for the paralysis. Whole spinal contrast-enhanced MRI showed improvement of high-signal intensity lesions, but paralysis clinically progressed in the left upper limb, both lower limbs, trunk, and phrenic nerve. Physical therapy enabled him to walk and raise his left shoulder, but the right upper limb paralysis persisted.

AFM is important as a differential diagnosis presenting with AFP. Cranial and whole spinal MR imaging findings are useful to diagnose AFM.