ECHO 25 focal encephalitis and subacute hemichorea

Area of Science:

• Neurology
• Virology
• Pediatrics

Background:

• Enterovirus infections can cause central nervous system (CNS) disease.
• Hemichorea as a manifestation of enterovirus CNS disease has not been previously reported.
• Focal encephalitis pathogenesis in enterovirus infections remains unclear.

Observation:

• A 5-year-old boy presented with unequivocal hemichorea.
• ECHO virus 25 was identified in cerebrospinal fluid (CSF) using indirect immunofluorescence and antibody rise.
• Computerized tomographic (CT) scans revealed a focal lesion in the left caudate nucleus evolving into a CSF-containing cyst.

Findings:

• This case represents the first documentation of ECHO virus 25 focal encephalitis presenting with hemichorea.
• ECHO virus antigen was detected in CSF cells, and the virus was typed as ECHO virus 25.
• Sequential CT analysis showed the development and resolution of a focal inflammatory lesion in the caudate nucleus.

Implications:

• The findings suggest a focal inflammatory process, rather than vasculitis, occlusion, or infarction, in the pathogenesis of this enterovirus-induced cerebral disease.
• Near-complete recovery despite permanent neostriatal tissue loss indicates that symptom resolution is not solely dependent on the integrity of this brain region.
• This case expands the known clinical spectrum of ECHO virus infections and highlights the potential for recovery in CNS enteroviral disease.