[A form of dopa-responsive dystonia of late onset with diurnal fluctuations]

We report a case of a 67-year-old woman who had dopa-responsive dystonia of late onset with diurnal fluctuations. She was well until the age of 65 years, when she noted the insidious onset of involuntary movements mainly involving the neck and trunk. She had no family history of movement disorders and had never received neuroleptics. Two years after her symptoms began, she visited our clinic. Neurological examination revealed slow repetitive extension and flexion movements of the neck and trunk, and irregular slow movements involving the mouth, tongue and limbs. The cranial nerves, cerebellar function, muscle strength, deep reflexes and sensory function were intact. Clinically and electromyographically, dystonia was characteristic of her involuntary movements. No parkinsonian features were present. The involuntary movements showed diurnal fluctuations that improved after sleep and the administration of L-DOPA and trihexyphenidyl. Dopamine receptor blocking agents aggravated her condition. Routine blood chemistry including copper metabolism, cerebrospinal fluid findings, and brain CT scan were all normal. Dopa-responsive dystonia is characterized by onset in childhood or adolescence and is frequently associated with parkinsonian features. Our patient had non-hereditary neck and trunk dystonia of late onset that responded to L-DOPA. Her disorder may constitute a specific form of dopa-responsive dystonia.