Relapsing polychondritis complicated by cognitive dysfunction: two distinct clinical phenotypes?

Relapsing polychondritis (RPC) is a rare, immune-mediated condition affecting approximately 3.5 per million population per year. Neurological involvement in RPC is still rarer and is presumed to be the result of a vasculitic process, although this is seldom confirmed in the literature. We present two cases of RPC complicated by cognitive dysfunction with contrasting clinical trajectories. Our findings suggest that there are two clinical phenotypes of cognitive dysfunction in RPC. The first is a fulminant, multisystem presentation with sub-acute cognitive decline mimicking central nervous system vasculitis, and we provide histopathological evidence of this process occurring. The other is an insidious cognitive decline without associated constitutional or systemic symptoms.