A case of radiculomyelitis following chickenpox in adulthood

A 34-year-old woman presented with numbness in both lower limbs and weakness of right lower limb twenty six days after a primary varicella infection (chickenpox) associated with fever and rash. Neurological examination revealed numbness of both lower limbs, more severe on the right side, mild paresis of the right lower limb, particularly in the tibialis anterior muscle, and absent ankle jerk on the right. After admission, hyperalgesia appeared at the thoracic 10 ~ 12 levels. The T ₂-weighted MRI of the spinal cord revealed a high signal intensity lesion at the Th 9 level and gadolinium enhancement was seen in that lesion as well as in the bilateral posterior radicles and the left anterior radix at the Th 9 level. On needle electromyography, fasciculation was found in the right tibialis anterior and gastrocnemius muscles. The temporal dispersion of F-wave was seen in the right peroneal nerve. We diagnosed the patient suffered from radiculomyelitis following the primary varicella infection. The secondary immunological mechanism rather than direct viral invasion is most likely in our patient, because (1) neither VZV DNA, nor anti-VZV antibody was positive in the CSF, and (2) the duration was relatively long between the development of skin rash and that of neurological symptoms.