Alternating hemidystonia following traumatic brain injury as an unusual presentation of paroxysmal autonomic instability with dystonia syndrome.

A 20-year-old man presented to the neurotrauma intensive care unit following blunt head injury. MRI revealed subarachnoid haemorrhage and multiple intraparenchymal haemorrhages suggesting severe brain injury. During recovery, the patient displayed intermittent episodes of alternating hemibody spasms with decerebrate/decorticate dystonic posturing. Episodes presented with autonomic dysregulation including hyperthermia, diaphoresis, tachypnoea, tachycardia and hypertension. Concern for seizure activity prompted simultaneous video monitoring and EEG testing. Results were without epileptiform activity suggesting against seizure as cause for alternating hemibody spasms. Paroxysmal autonomic instability with dystonia (PAID) was considered despite the unusual presentation. Intravenous hydromorphone was used for treatment, which relieved symptoms of autonomic dysregulation and dystonic posturing. PAID syndrome was diagnosed based on presentation with intermittent episodes of dystonia, autonomic dysregulation, absence of epileptiform activity and rapid response to opioid treatment. This case illustrates the clinical variability of this uncommon syndrome because alternating hemidystonia as main manifestation has not been previously described.