It's cause is usually feeding them table food. If you do a search on this site, you will find lots of info about it. Never feed them greasy human food. I'm sorry she's so sick. Her diet from now on will need to change.
Here is some info that will help you understand it.
Rich, fatty foods can be very dangerous to dogs susceptible to attacks of pancreatitis. Often you may not know that your dog is susceptible until he is very sick with his first attack. It is often the smaller, more energetic breeds like miniature or toy poodles, cocker spaniels, miniature schauzers, and other small terrier-type dogs who seem particularly prone. However, any dog may have a problem. It is best to avoid these foods altogether. turkey skin bacon, sausages, hot dogs fruit cake, plum pudding deep-fried Signs of pancreatitis generally include an acute onset of vomiting (sometimes with diarrhea) and abdominal pain, which may be evidenced as a hunched posture or "splinting" of the abdomen when picked up. The dog may become very sick quickly and often needs intensive fluid and antibiotic therapy.
http://mooreshaven.com/pets/dogs/saf...foodslist.html
Here is another link on care:
http://www.mscc.ca/pancreatitis.html