Focal dystonia attributed to secondary Nigrostriatal pathway disruption following brainstem Hemorrhage: a case report

Focal dystonia is an uncommon movement disorder that may emerge secondary to structural brain lesions. This report presents a rare case of delayed-onset, levodopa-responsive hemidystonia following a brainstem hemorrhage with suspected disruption of the nigrostriatal pathway.

A 58-year-old man developed sustained dystonic posturing of the left upper and lower limbs one year after suffering a right-sided pontine-midbrain hemorrhage. MRI demonstrated hypointensities in the right substantia nigra and red nucleus, consistent with hemosiderin deposition. Levodopa was initiated at 300 mg/day and titrated to 600 mg/day over 4 weeks, resulting in marked symptomatic improvement. No craniofacial dystonia or parkinsonism was observed.

Delayed-onset dystonia can arise from secondary degeneration or iron deposition within the nigrostriatal system. This case highlights the importance of advanced imaging and therapeutic trial of dopaminergic agents in post-lesional dystonia. Literature review indicates similar pathophysiological mechanisms in post-stroke dystonia, although levodopa-responsiveness is rarely reported.