Progressive delayed-onset dystonia after cerebral anoxic insult in adults.

The basal ganglia, especially the globi pallidi (GP), are highly vulnerable to generalized cerebral anoxia/hypoxia. We report on 2 new cases with delayed-onset generalized dystonia due to cerebral anoxia. The onset of dystonia in both of our patients was delayed by about 2 months. In both cases, the unusual feature was the progressive worsening and the spread of dystonia over many years after delayed onset. Dystonia progressed for 16 years in Case 1 and for 4 years in Case 2. Furthermore, initial magnetic resonance imaging (MRI) scan of Case 1 showed mild changes of the internal capsule sparing the basal ganglia. Years later, in line with clinical progression, the follow-up MRI scan showed isolated bilateral lesions involving the entire GP. MRI scans in Case 2 showed bilateral lesions of caudate and lentiform nuclei. There may be several mechanisms underlying delayed and progressive symptoms after time-limited brain anoxia. We hypothesize that anoxia-induced excitotoxicity resulting in mitochondrial dysfunction and subsequent apoptosis may explain, at least partly, the delayed-onset and progressive extrapyramidal syndromes seen in these patients.