However, other disorders can mimic CJD and must be considered; they include Central nervous system (CNS) vasculitis Rapidly progressive Alzheimer disease Hashimoto encephalopathy (an autoimmune encephalopathy that is characterized by high thyroid antibody levels and that responds to corticosteroids) Intravascular lymphoma (a rare lymphoma) Encephalitis that affects the limbic system, brain stem, and cerebellum Lewy body dementia Intoxication with lithium or bismuth.