This chapter talks about a 39-year-old woman who was reported to the "German National Reference Center for the Surveillance of Transmissible Spongiform Encephalopathies" (NRC). The patient's medical history comprised allergic asthma, hyperlipidemia, nasal sinus surgery, and pulmonary embolism. The family's medical history comprised allergies, asthma, and psoriasis, cerebrovascular disease, colon cancer, but no early onset dementia. The combination of rapidly progressive dementia, psychosyndrome, ataxia, visual disturbances, and the Pulvinar Sign revealed by MRI as well as the exclusion of encephalitis or many other possible causes of that symptom constellation made the involved physicians consider a prion disease, namely variant Creutzfeldt-Jakob disease, as a differential diagnosis. Rapidly progressive dementia, the "Hockey Sticks" and the exclusion of encephalitis led to the diagnosis of variant Creutzfeldt-Jakob disease (vCJD) in the first place. Wernicke's disease was not as strongly considered initially since the patient was non-alcoholic.

Dementia is a syndrome, not a specific diagnosis. There are more than 70 recognized disorders that cause dementia and the ultimate responsibility of determining the precise cause of dementia lies with a multidisciplinary team or dementia clinic. Mild dementia, however, is often missed unless mental status is formally assessed. Transient global amnesia (TGA) is a rare, but dramatic entity with a benign prognosis. TGA is characterized by abrupt, temporary inability to form new memories (anterograde amnesia) and variable impairment of recent and remote memory. TGA spares nonmemory functions, such as language and visuospatial skills. The diagnostic evaluation of dementia is best done in the outpatient setting. Common complications, such as pneumonia and urinary tract infection, are considered in demented patients with a precipitous decline in cognition. Infectious precautions are required when evaluating patients with rapidly progressive dementia.