MERS-Mild Encephalopathy with Reversible Splenial Lesion: Case Study in a Pair of Siblings

Objective: MERS (mild encephalopathy with reversible splenial lesion) is being increasingly recognized with the availability of accessible neuro-imaging. This condition is more common in paediatric age group rather than in adults.

Methods: We report a case of a pair of siblings aged 3 and 4 years old presenting with acute onset of encephalopathy. They presented with fever, vomiting and abdominal pain initially which raised concerns for an evolving gastro-intestinal infection. Subsequently both siblings developed seizures with progressive encephalopathy requiring neuro-imaging.

Results: The siblings were initially suspected to have suspected poisoning or drug overdose as they came from a high-risk family with a history of parental drug usage and complex social background. However, the drug screen was negative and there was no clinical evidence of a toxidrome. There was significant pleocytosis in both their cerebrospinal taps but further investigations for infective and metabolic causes returned negative with electroencephalogram (EEG) showing generalized slow waves in both patients. MRI brain showed restricted diffusion at the splenium of the corpus callosum in both siblings which had resolved when a repeat MRI brain was done in 3 weeks time. They had no long-term neuro-disability and made full recovery of their function within 1 month.

Conclusion: MERS is an important differential diagnosis to consider in children presenting with encephalopathy. The prognosis of the condition is known to be excellent with minimal neuro-disability reported in literature. It is vital to give due recognition to this entity to ensure appropriate management and counselling of the patients and their caregivers. We are also postulating familial or genetic factors that make certain individuals more susceptible to MERS in view of this case report where 2 siblings were affected simultaneously likely triggered by an underlying infective etiology.