Introduction
Mild encephalitis/encephalopathy with a reversible splenial lesion
syndrome (MERS) is a rare clinical-radiological syndrome. It was first
identified by Carlos Garcia-Monco [1] in 2011. The most
common neurological symptoms are behavioral changes, altered
consciousness and seizures [2]. The diagnosis is based on
Brain magnetic resonance imagings (MRIs) showing a transient anomalies
mainly in the corpus callosum or sometimes extending to adjacent
parenchyma [1]. This syndrome mostly recovers without
treatment [1]. Biotherapy was reported to be efficient in
MERS in some cases. [3, 4] This syndrome was reported in
patients with viral infections, particularly rotavirus, herpes simplex
virus, adenovirus, coxsackie virus, echoviruses, mumps, influenza A/B
virus, and recently SARS CoV-2 [5-12]. In few cases MERS
was induced by some drugs such ipilimumab [13] and mumps
vaccination [14]. Here, we describe an original case of
MERS appearing few hours after RTX treatment in a patient with IgG4-RD.