Matt, I suppose that it's not particularly useful to know, however our two - year old Bengal suddenly began to suffer exactly those symptoms earlier in the year. Much investigation and a substantial vets bill later (could probably have bought another bike for that money) a swollen pancreas was found through an ultrasound examination and medication administered. two days later, the cat was back to normal with so far, no recurrence.
The vet(s) - it took two to find the problem said that this was a rare but not unheard of problem, that probably resulted from ingesting something unsuitable.
As I said, maybe of no value but it just might help!
