Vasogenic Edema Covering the Brain Surface in a Case of Severe Meningoencephalitis Due to Varicella-Zoster Virus Infection

Meningoencephalitis caused by varicella-zoster virus (VZV) is a serious condition requiring prompt antiviral treatments, but magnetic resonance imaging (MRI) findings are often normal, limiting early diagnostic utility. We report a case of severe VZV-associated meningoencephalitis characterized by diffuse T2 hyperintense lesions covering the brain surface on MRI, presumed to be vasogenic edema. An immunocompetent 78-year-old Japanese woman presented with a disturbance of consciousness preceded by seven days of headache. On admission, she was in a semi-coma with intermittent convulsive seizures and had a localized skin rash with blisters on her back. Brain MRI showed diffuse T2 hyperintensity on the brain surface with an elevated apparent diffusion coefficient and the marked gadolinium-contrast enhancement of the pia-arachnoid membrane and vessel walls. Polymerase chain reaction using cerebrospinal fluid revealed the presence of VZV, and then she was diagnosed with VZV-associated meningoencephalitis. Treatment with acyclovir and corticosteroids was initiated, leading to some clinical improvement; however, the patient developed acute non-occlusive mesenteric ischemia and died on the 10th day of hospitalization. The characteristic MRI findings observed in our patient may be useful in considering the pathogenesis and early diagnosis of this rare entity.