What question did this study set out to answer?

The aim is to report two pediatric cases of mild encephalitis/encephalopathy with reversible splenial lesions, emphasizing diagnosis and recovery.

March 13, 2026Open Access

Mild Encephalitis/Encephalopathy With a Reversible Splenial Lesion of the Corpus Callosum (MERS): A Report of Two Pediatric Cases

Q: What is the clinical evidence from this study?

Study design: Case Report. Population: Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion of the Corpus Callosum (MERS) (n=2). Primary outcome: Neurological recovery and resolution of MRI lesions.

Key Result

Neurological recovery was rapid and complete in both children, confirming the diagnosis of MERS with complete resolution of MRI lesions by follow-up.

Key Points

The aim is to report two pediatric cases of mild encephalitis/encephalopathy with reversible splenial lesions, emphasizing diagnosis and recovery.
Case reports of two pediatric patients in the emergency department
Clinical assessments including neurological examinations
Brain MRI to identify lesions in the splenium of the corpus callosum
CSF and infectious workups performed
Follow-up MRI to assess resolution of lesions
Both patients exhibited rapid and complete neurological recovery
MRI showed diffusion-restricted lesions in the splenium without contrast enhancement
One patient tested positive for respiratory viral PCR, suggesting a viral etiology
Full resolution of lesions was confirmed on follow-up MRI

Study Design

Type

Case Report (n=2)

Multicenter

Structured PICO

Population

Two pediatric patients (a 23-month-old boy and an 8-year-old boy) presenting with acute neurological symptoms (seizures, dysarthria, ataxia) following viral infections.

Intervention

Supportive management and MRI imaging

Outcome

Clinical recovery and radiological resolution of splenial lesions

MERS is a reversible and self-limiting cause of pediatric encephalopathy characterized by transient splenial lesions on MRI, requiring early recognition to avoid unnecessary interventions.

Limitations

Small sample size
Nature of case report limits generalizability

Abstract

Mild encephalitis/encephalopathy with a reversible splenial lesion of the corpus callosum (MERS) is an uncommon clinico-radiological syndrome marked by transient lesions of the splenium, which are typically demonstrated as diffusion-restricted hyperintensities on MRI. It presents with acute neurological symptoms such as seizures, dysarthria, or ataxia, often following viral infections. We report two pediatric cases of MERS observed in the ED. The first was a 23-month-old boy with focal status epilepticus in the setting of acute gastroenteritis. The second was an eight-year-old boy who presented with dysarthria, gait ataxia, and sensorimotor deficits after a febrile viral illness. Brain MRI in both patients showed diffusion-restricted lesions in the splenium of the corpus callosum, with no contrast enhancement. CSF and infectious workups were unremarkable, except for positive respiratory viral PCR in one case. Neurological recovery was rapid and complete in both children. Follow-up MRIs demonstrated full resolution of the lesions. These clinical and radiological patterns confirmed the diagnosis of MERS. These cases highlight the importance of recognizing MERS as a reversible and self-limiting cause of pediatric encephalopathy. Early MRI is crucial for diagnosis, avoiding unnecessary interventions, and guiding supportive management. Awareness of MERS and its typical imaging features is essential for clinicians and radiologists dealing with pediatric neurological presentations.

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