The pathophysiology of akathisia is not well understood, but hyporeactivity or blockade of the striatal dopaminergic system and dopamine-acetylcholine imbalance is implicated.  Akathisia is often encountered in patients taking phenothiazines, more specificity with dopamine2-receptor antagonists.  While para- and post-infectious etiologies of akathisia in the setting of striatal injury have not been fully explored, there are similar descriptions of Restless Leg Syndrome occurring in the setting of mycoplasma and streptococcal infections, presumably due to striatal dopaminergic dysfunction.  Typical akathisia treatments include propranolol, mirtazapine, cyproheptadine or anticholinergic agents. 

Case Description:

A 5-year previously healthy boy presented with multiple febrile seizures.  MRI brain demonstrated diffuse leptomeningeal thickening and enhancement.  He was diagnosed with Epstein-Barr Virus (EBV) encephalitis based on cerebrospinal fluid PCR testing and serology.  He returned to baseline over the next week and he was discharged to home with supportive care.  One week later, he presented in status epilepticus and was intubated for airway protection.  Fentanyl and dexmedetomidine drips were initiated and continued for sedation.  Repeat MRI brain revealed T2-weighted/FLAIR hyperintense signal in bilateral caudate, putamen and hypothalamic regions, which has previously been described in EBV encephalitis.  He was treated with 14 days of intravenous acyclovir and 5 days of high-dose methylprednisolone followed by oral prednisone taper over the next 6 weeks. Once extubated and off potential offending medications, he exhibited agitation and restless movements in which he frequently repositioned himself in bed, or stood up and walked in his room; he was unable to sit or lay still.  He was diagnosed with akathisia, thought to be secondary to his striatal injury, and started on trihexyphenidyl with improvement in his movement disorder. 

Akathisia may emerge post-infectiously in the setting of EBV encephalitis, likely due to impairments in the striatal dopamine pathway.  Symptoms may be treated with anticholinergics such as trihexyphenidyl.