[Posterior Reversible Encephalopathy Syndrome (PRES) induced by Rituximab in two patients with vasculitis, and treated by hemodialysis].

: Small and medium vessel vasculitides, either ANCA-associated or caused by anti-GBM antibodies, are multisystemic diseases with predominantly renal involvement that often require dialysis support; clinical remission can be induced with immunosuppressive therapies including apheretic treatments, high doses of steroids, and immune suppressants. In addition to the complications resulting from the primary pathological process, those associated with the immunosuppressive therapies are not negligible. Reversible Posterior Encephalopathy Syndrome (PRES) is a clinical condition with a hyperacute onset, which can complicate the evolution of vasculitides while treated by immunosuppressive therapy. Relevant pathogenic factors are represented by alterations of the cerebral blood-brain barrier or vasogenic and/or brain edema phenomena, also related to uncontrolled hypertension. We describe two cases of patients with systemic vasculitides, rapidly progressive renal failure (RPGN) requiring dialysis, and poor response to the initial immunosuppressive therapy who were treated subsequently with rituximab. PRES developed immediately after administration of the drug, which, however resulted effective on the course of the vasculitis in one case and not effective in the other. In both cases, the subsequent radiological controls showed a total resolution of the encephalic alterations observed during the acute phase.