Efficacy of dextromethorphan and cyclosporine a for acute encephalopathy

Acute encephalopathy with biphasic seizures and late reduced diffusion was recently established clinicoradiologically as an encephalopathy syndrome. The outcome of this encephalopathy is characterized by a low mortality rate and high incidence of neurologic sequelae. Although the exact pathogenesis of this encephalopathy is uncertain, excitotoxic injury with delayed neuronal death is proposed. On the basis of this hypothesis, we tried a combination therapy of N-methyl-D-aspartate receptor antagonist, dextromethorphan, and apoptosis inhibitor, cyclosporine A, in four patients with acute encephalopathy with biphasic seizures and late reduced diffusion. All patients recovered except for hyperactivity in one patient. Furthermore, an additional four patients with near-miss encephalopathy, who showed mild disturbance of consciousness at 24 hours after prolonged febrile seizures associated with exanthem subitum, recovered without secondary seizures by the early administration of dextromethorphan. The combination regimen of dextromethorphan and cyclosporine A could be effective for the treatment and prevention of acute encephalopathy with biphasic seizures and late reduced diffusion.