[A case of chronic thinner intoxication developing hyperkinésie volitionnelle three years after stopping thinner...

We reported a 25-year-old male with chronic thinner intoxication. He had been sniffing thinner from the age of 15 to 20. Since the age of 20, he developed gait disturbance, weakness of lower extremities, and scanning speech. At the age of 23, three years after he stopped sniffing thinner, he had hyperkinésie volitionnelle (HV) of bilateral upper extremities. MRI study revealed diffuse high intensity areas in the cerebral white matter, thinning of the corpus callosum, and cerebellar and brainstem atrophy on T1 weighted images. On T2 weighted images, low intensity areas in the thalamus, the striatum, the anterior limb of the internal capsule, the tegmentum of midbrain, high intensity areas in middle cerebellar peduncle, the posterior limb of the internal capsule, the lateral part of the cerebral peduncle, and the cerebral white matter were noted. HV almost disappeared with 2.5 mg of clonazepam daily administered. The disappearance of HV by ischemic compression of his arm suggested that input from the periphery might be relevant to the etiology of HV. The time interval between exposure to thinner and the recognition of HV in our case was in agreement with that between the occurrence of cerebrovascular disease and the recognition of HV in the previous reports. We postulated that HV in this case was the manifestation of the denervation hypersensitivity in the dentatorubroolivary system.