Final answer:
A 78-year-old woman with memory loss, myoclonus, startle response, and seizures, particularly after a corneal transplant, is likely suffering from Creutzfeldt-Jakob disease (CJD), a rapidly progressing neurodegenerative disorder.
Step-by-step explanation:
The clinical presentation of a 78-year-old female with memory loss, myoclonus, startle response, and seizures, particularly following a corneal transplant, suggests she may have Creutzfeldt-Jakob disease (CJD), which is a type of transmissible spongiform encephalopathy (TSE). CJD is characterized by rapid cognitive decline, the presence of 14-3-3 protein in the cerebrospinal fluid, abnormal EEG resembling neurodegenerative diseases, and sponge-like lesions in the brain due to abnormal prion proteins as highlighted in figure 6.26. It is to be distinguished from Alzheimer's disease which progresses more slowly and involves the accumulation of amyloid plaques and neurofibrillary tangles in the brain, as noted in figure 26.30. Unlike Alzheimer's, CJD progresses quickly, leading to severe cognitive and motor dysfunction and typically culminates in death within a year of diagnosis.