[Successful treatment of the backward-bending attack due to generalized spasm in stiff-person syndrome with intravenous immune globulin therapy].

We report a 63-year-old man with stiff-person syndrome, who dramatically responded to the treatment with high dose intravenous immunoglobulin (IVIG). He developed stiffness of the right leg and low back five years ago. He was treated with oral diazepam 6 mg/day and showed a marked improvement. He had been maintained on the same dose since then. In 2000, he began to have episodic generalized spasm and painful spasm of his left leg as well as persistent stiffness of his legs and low back. Findings on the physical examination were normal except for a prominent hyperlordosis with co-contracture of the lumbar paraspinal and abdominal muscles. Neurologic examination revealed stiffness in the lower limbs, more marked on the left side, and lower truncal muscles. The left leg had painful spasm, which was provoked by tactile stimuli. There was severe generalized spasm which made him suddenly bend backward. These backward-bending attacks were provoked spontaneously or reflexively by sudden tactile stimuli. He was unable to arise from a chair or stand without assistance. His deep tendon reflexes on both legs were brisk and Babinski sign was negative. He had no diabetes mellitus and thyroid function was normal. Antibodies against glutamic acid decarboxylase(GAD), antinuclear antibody, thyroid peroxidase autoantibody and antithyroglobulin autoantibody in the serum were present. His painful spasm was disappeared and muscle stiffness was moderately improved by treatment with oral diazepam and clonazepam, but backward-bending attacks due to generalized spasms were not controlled. He received IVIG. Three days after the administration of IVIG, these attacks disappeared completely. Subsequently muscle stiffness improved. One week after, he was able to walk without assistance. IVIG may be useful for treatment of generalized spasm, which had no response to treatment with diazepam or clonazepam.