[Stiff-person syndrome with elevated anti-Epstein-Barr virus antibody].

Stiff-person syndrome, a relatively rare disease with a poor prognosis, presents as muscle stiffness, rigidity, and spasm. We reported a patient with this syndrome who was treated successfully. The patient was a 56-year-old Japanese man with respiratory infection-like prodromal symptoms. Episodes of painful spasm in both legs on extension and lordosis occurred spontaneously or were triggered with touch or pinprick stimuli at or below spinal level C3, and progressed subacutely. Tendon reflexes were hyperactive, Babinski's sign was positive, and vibration sense was reduced in the legs. Episodes of spasm were alleviated using diazepam. Even after discontinuing diazepam, these symptoms did not exacerbate. In this patient, although anti-glutamic acid decarboxylase (GAD) antibody was negative, anti-EB virus antibody was positive. No previous reports have described stiff-person syndrome with EB virus infection. However, a few cases of this syndrome associated with viral infection were recently reported and viral gene mimicity with GAD has been postulated. Viral infection might be considered as a probable cause of this syndrome.