Pediatric DYT-TOR1A dystonia presenting as functional neurological disorder: A case report

Functional neurological disorders are neurologic symptoms without a structural basis but can be difficult to distinguish from symptoms caused by structural brain differences (organic neurological disorders). We present a pediatric patient who was diagnosed with functional neurological disorder and determined years later to also have an organic movement disorder, DYT-TOR1A. She was treated with deep brain stimulation with very good response. Historical features, exam findings are helpful in distinguishing functional neurological disorder from an organic movement disorder, and gauging response to treatment and clinical features over time help physicians ensure diagnostic accuracy. However, the diagnostic process is particularly challenging when functional neurologic disorder and organic dystonia are present in the same patient. • Functional neurological disorder (previously called “conversion disorder”) present as a variety of neurological symptoms that have no structural basis but rather represent disorders of network function in the brain. • Functional dystonia can be difficult to distinguish from organic dystonia, as both conditions present with abnormal movements that worsen with stress and there is no diagnostic test. • Functional dystonia is treated with physical therapy and cognitive behavioral therapy and organic dystonia is treated with medications, botulinum toxin injections or deep brain stimulation. • Features that may suggest functional dystonia include a rapid onset of symptoms, pain, cognitive symptoms and comorbid mood disorders. Gauging response to treatment can also improve diagnostic accuracy.