Where: Southern Ontario, Canada
Searched: Wikipedia - pretty much every illnessin the list of fatal diseases, illnesses. Google: Fatal disease information, fatal illness information. Including fatal familial insomnia, which doesn't work for what I need but terrifies me all the same.
Question: I'm currently working on a story based around a seventeen-year-old girl who learns she has three weeks to live. She's relatively healthy, in diet and activity. She also doesn't show major signs of slowing down until the last four or so days of her life. Is there an illness that roughly fits these parameters?