Progressive delayed hemidystonia following clinically mild traumatic brain injury.

A 16-year-old boy presented with progressive left hemidystonia over 3 years. The possibilities of symptomatic hemidystonia due to focal lesions such as infarct (vasculitis), tumours, tuberculoma, arteriovenous malformations or heredodegenerative disorders such as Wilson disease were considered. Imaging showed a peculiar scar involving right basifrontal region extending upto anterior, centromedian and dorsomedial nuclei of thalamus due to blowout fracture of roof of orbit. This scar was responsible for progressive left hemidystonia. On probing the history, it was revealed that patient had sustained a mild traumatic brain injury (mTBI) 3 years ago. Burke-Fahn-Marsden dystonia severity rating scale showed improvement from 19 to 6 after treatment with tablet trihexyphenidyl 16 mg and clonazepam 1 mg. A linear scar reaching upto thalamus due to blowout fracture of roof of orbit following clinically mTBI is unique. Delayed, progressive hemidystonia has been reported following severe head injury, however is less common following clinically mTBI.