A case of enteroviral meningoencephalitis presenting as rapidly progressive dementia

Abstract

Background: A 70-year-old immunocompetent male presented to a memory disorders clinic with a 7-month illness that had begun with somatic complaints including transient right temporal head pain, left buttock pain, and right conjunctival injection. About 3 months after the first signs of illness, the patient had begun to develop insidious cognitive and behavioral decline, which progressed most rapidly in the 2 months before presentation. An assessment completed during hospitalization for intermittent fevers and confusion had not revealed an infectious etiology, although mild pleocytosis in the cerebrospinal fluid had been noted. Upon presentation to the memory disorders clinic, the patient was disoriented, distractible, laughed at inappropriate moments, and followed only one-step commands. He had hypophonic speech and had mildly increased axial tone. He scored 5 out of 30 on the Mini Mental State Examination and was admitted for expedited evaluation.

Investigations: Physical examination, brain MRI, electroencephalogram, lumbar puncture, autoimmune and paraneoplastic testing, cerebral angiogram, cerebrospinal fluid analysis, enterovirus group-specific reverse transcriptase polymerase chain reaction assay, and RNA sequencing in brain biopsy samples.

Diagnosis: Enteroviral meningoencephalitis.

Management: Intravenous steroids with oral taper and intravenous immunoglobulin.

Figure 1

MRI scans of the patient’s brain before surgery. (A–C) A FLAIR sequence demonstrated hyperintensities in gray and white matter, particularly in the medial temporal lobes (A,C) and in the right anterior cingulate cortex (B), basal ganglia (B) and left insula (B,C). (D) On a T1-weighted coronal sequence with contrast, there are small regions of contrast enhancement (arrows) in the left insula and left temporal lobe, corresponding to FLAIR hyperintensities. Abbreviation: FLAIR, fluid-attenuated inversion recovery.

Figure 2

A brain biopsy specimen stained with hemotoxylin and eosin showed foci of microglia and lymphocytes involving the leptomeninges and neuropil. The specimen also exhibited diffuse parenchymal gliosis (not shown).