An Unusual Neurological Masquerade: Stroke-like Presentation of Herpes Simplex Virus-1 Encephalitis with Opsoclonus and Chorea

Herpes simplex virus encephalitis (HSVE-1) is an uncommon but serious pediatric neuroinfection, usually presenting with seizures, altered consciousness, and focal neurological deficits. We describe a one-year-old girl who presented with fever-triggered right focal seizures and hemiparesis, which rapidly progressed to spastic quadriparesis with encephalopathy. Initial neuroimaging suggested ischemic stroke. However, the baseline stroke work-up was negative. Cerebrospinal-fluid polymerase-chain-reaction subsequently confirmed HSV-1 infection. Magnetic-resonance-imaging revealed asymmetric cortical and subcortical involvement of the posterior-frontal, parietal, and thalamic regions, notably sparing the temporal lobes – an unusual neuroradiological pattern for HSVE-1. The course was further complicated by raised intracranial pressure and the emergence of opsoclonus, an exceptionally rare manifestation in this context. Management included intravenous acyclovir for 3 weeks, antiedema measures, and multiple antiseizure medications. Gradual recovery occurred, with resolution of opsoclonus and partial improvement in sensorium, motor strength, and social interaction. The child had to be readmitted with complaints of persistent right hemiparesis, gaze preference to the left, and new-onset chorea. This HSVE-1 is remarkable for its combination of a stroke-like presentation, the neuroimaging revealing temporal lobe sparing, spastic quadriparesis during the acute phase, raised intracranial pressure, opsoclonus, and chorea. While HSVE-1 has been reported as a stroke-mimic in adults, pediatric data are limited. Quadriparesis in the acute stage is rarely described. Opsoclonus, to our knowledge, has not been previously reported in children with HSVE-1. Via this unique constellation of features, we emphasize the variable clinical and radiological spectrum of pediatric HSVE-1. Recognition of such atypical presentations is essential for timely diagnosis, appropriate management, and improved outcomes in affected children.