For the majority of cases, the cause is unknown. In dogs, obese middle age to older animals have a higher incidence, as do females. Even though exact causes are not known, there are identifiable risk factors. some potential risk factors are:
Hyperlipidemia (high fat content in blood)
High fat meal (trigger for hyperlipidemia)
Obesity (especially dogs)
Concurrent disease - i.e. Cushing's, Diabetes
Contaminated food or water
Certain drugs and toxins - i.e. some types of diuretics, antibiotics, and organophosphate insecticide
Bacterial or viral infection