Mild encephalopathy with a reversible splenial lesion syndrome (MERS) Is
this a new side effect of Rituximab?
Abstract
Mild encephalitis/encephalopathy with a reversible splenial lesion
syndrome (MERS) is a rare clinico-radiological entity. Its occurrence
after Rituximab (RTX) has never been described. We report the first case
of MERS following RTX in a patient treated for IgG4 related disease
(IgG4-RD). It was about a 33-year-old patient diagnosed since 2017, with
an IgG4-RD. This diagnosis was made in front of a prolonged fever, sicca
syndrome, hepatic damage and renal pseudotumor associated to a high
level of IGg4 at 2.8 g/l with suggestive renal histology. The patient
was treated with corticosteroid therapy with persistence of renal
impairment and nephrotic syndrome that’s why RTX has been indicated. The
patient received his first dose of RTX and presented few hours after,
neurological and respiratory impairments. An infectious investigation
comprising a SARS CoV-2 PCR and viral PCRs (VZV, Herpes and CMV) on
cerebrospinal fluid (CSF) were negative. The HBV, HCV, HIV, Parvo B19,
CMV, EBV, Herpes, Mycoplasma and syphilis serologies as well as
Legionella antigenuria were also negative. The patient had received
methylprednisone boli, intravenous immunoglobulin’s associated with
sodium valproate with good evolution. The diagnosis of MERS induced by
RTX is likely. However the viral aetiology is not excluded.