Great question!
Persistent fasting hyperlipidemia is abnormal and can be either primary or secondary to other diseases or drug administration. Secondary hyperlipidemia is the most common form of hyperlipidemia in dogs. Most commonly, secondary canine hyperlipidemia is the result of an endocrine disorders. Primary lipid abnormalities are usually, but not always, associated with certain breeds. Depending on the breed, the prevalence of a primary lipid abnormality can vary widely. Primary hyperlipidemia is very common in Miniature Schnauzers. Primary hyperlipidemia in the Miniature Schnauzer is typically characterized by hypertriglyceridemia with or without hypercholesterolemia. Primary hyperlipidemias have also been reported in Shetland Sheepdogs (in Japan and possibly other countries), Beagles, Briards, a family of rough-coated Collies from the United Kingdom,18 and anecdotally in Doberman Pinschers and Rottweilers.
Hyperlipidemia itself does not seem to lead directly to the development of major clinical signs, it has been shown to be associated with the development of other diseases that are clinically important and potentially life-threatening. Hyperlipidemia, and more specifically hypertriglyceridemia, has long been suspected as a risk factor for canine pancreatitis. The results of two recent clinical studies provided stronger evidence that hypertriglyceridemia, especially when severe (>900 mg/dL), is a risk factor for pancreatitis in Miniature Schnauzers. Therefore, severe hypertriglyceridemia in Miniature Schnauzers should be treated even when clinical signs are not present, due to the risk of developing pancreatitis. In summary, I would treat (mostly with low-fat diet) in Miniature Schnauzers.
In other breeds, a more general and wide selection of tests might be necessary for patients that have vague or no clinical signs. It should be noted that dogs with hyperlipidemia are often clinically healthy. It is likely that at least some of these dogs have some form of primary hyperlipidemia. If it is mild or moderate, there may be no need for detailed diagnostic investigations. If hypercholesterolemia is the main abnormality (without or with only mild hypertriglyceridemia), then it is more likely that the dog has some form of secondary hyperlipidemia, warranting recommendations for further diagnostic investigation.
I hope that helps a little bit. Let me know if that makes sense.
Scott 🙂
