Mild encephalopathy with reversible splenial lesion (MERS) is a recently described clinico-radiological syndrome. It is characterised by acute mild encephalopathy and changes in the splenium of the corpus callosum on brain magnetic resonance imaging (MRI). MERS has been described mainly in East Asian populations. Infection, particularly influenza, is the most common association. The prognosis is generally favourable with spontaneous resolution of clinical and radiological abnormalities. We report two cases of non-influenza MERS in children, one associated with varicella, and discuss their differing clinical presentations.
TadaHTakanashiJBarkovichAJObaHMaedaMTsukaharaH. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion. Neurology2004;63(10):1854–8.
2.
TakanashiJ. Two newly proposed infectious encephalitis/encephalopathy syndromes. Brain Dev2009;31(7):521–8.
3.
FlussJFereySMenache-StarobinskiCDelavelleJVan BogaertPVargasMI. Mild influenza-associated encephalopathy/encephalitis with a reversible splenial lesion in a Caucasian child with additional cerebellar features. Eur J Paediatr Neurol2010;14(1):97–100.
4.
HaraMMizuochiTKawanoGKoikeTShibuyaIOhyaT. A case of clinically mild encephalitis with a reversible splenial lesion (MERS) after mumps vaccination. Brain Dev2011;33(10):842–4.
5.
YehIBTanLCSitohYY. Reversible splenial lesion in clinically mild encephalitis. Singapore Med J2005;46(12):726–30.
6.
ChoJSHaSWHanYSParkSEHongKMHanJH. Mild encephalopathy with reversible lesion in the splenium of the corpus callosum and bilateral frontal white matter. J Clin Neurol2007;3(1):53–6.
7.
HashimotoYTakanashiJKaihoKFujiiKOkuboTOtaS. A splenial lesion with transiently reduced diffusion in clinically mild encephalitis is not always reversible: A case report. Brain Dev2009;31(9):710–2.
8.
HondaKNishimiyaJSatoHMunakataMKamadaMIwamuraA. Transient splenial lesion of the corpus callosum after acute withdrawal of antiepileptic drug: A case report. Magn Reson Med Sci2006;5(4):211–5.
9.
ImamuraTTakanashiJYasugiJTeradaHNishimuraA. Sisters with clinically mild encephalopathy with a reversible splenial lesion (MERS)-like features; Familial MERS?J Neurol Sci2010;15;290(1–2):153–6.
FrieseSABitzerMFreudensteinDVolgtKKükerW. Classification of acquired lesions of the corpus callosum with MRI. Neuroradiology2000;42(11):795–802.
12.
MorichiSKawashimaHIoiHYamanakaGKashiwagiYHoshikaA. High production of interleukin-10 and interferon- γ in influenza-associated MERS in the early phase. Pediatr Int2012;54(4):536–8.
