Hyperlipidemia in Dogs

Hyperlipidemia in dogs is characterized by abnormally high levels of fat in the blood. We distinguish between hypertriglyceridemia, which involves excess triglycerides, and hypercholesterolemia, which involves excess cholesterol.

Hyperlipidemia in dogs can be the result of hypertriglyceridemia, hypercholesterolemia, or both.

What Is Hyperlipidemia?

We further distinguish between primary and secondary hyperlipidemia. Primary hyperlipidemia occurs for reasons unknown but appears to be hereditary, because it predominantly affects specific breeds of dogs. Secondary hyperlipidemia occurs as a result of another disease, with endocrine disorders such as diabetes, hypothyroidism, and hyperadrenocorticism (Cushing's disease) being the most common culprits.

Other documented causes of secondary hyperlipidemia in dogs include liver disease, kidney disease, and obesity. For more information on primary and secondary hyperlipidemia in dogs, including an examination of the mechanisms by which various disorders produce lipid abnormalities and a discussion of the culpability of high fat diets, see What Is Hyperlipidemia?

Clinical Signs of Hyperlipidemia in Dogs

Dogs with hyperlipidemia may be asymptomatic, or they may present with one or more clinical signs. Gastrointestinal symptoms such as abdominal discomfort, vomiting, diarrhea, and anorexia are perhaps the most common symptoms. Among the most serious signs of hyperlipidemia is acute pancreatitis, a potentially life-threatening inflammation of the pancreas.

Also in the serious category are seizures and neurological disturbances. Persistently high lipid concentrations in the blood can result in fatty deposits in eyes, arteries, and abdominal organs. Liver and gall bladder problems are also a possibility. For more information, see Clinical Signs of Hyperlipidemia, which also provides a detailed discussion of the tests used to diagnose hyperlipidemia in dogs.

Fat Metabolism in Dogs

To gain a better understanding of hyperlipidemia in dogs, it is very helpful to know how canine lipid metabolism is supposed to work. Fat Metabolism in Dogs will provide you with a description of both metabolic pathways: the exogenous pathway which concerns itself with the metabolism of external or dietary lipids, and the endogenous pathway which facilitates the metabolism of internally produced lipids.

We'll begin by following a fat-containing meal from the moment your dog swallows the food to the point where the lipids are absorbed into muscle or fat cells to be burned for energy or stored as an energy reserve, covering all the fat digestion and absorption processes involved in making that happen.

Then we'll move on to the metabolism of internally synthesized fats, where you'll learn about the various lipoprotein classes in charge of transporting endogenous fats. This is important because canine lipoprotein metabolism has some unique features, and impairment of lipoprotein metabolism is a common factor of disorders causing hyperlipidemia in dogs.

Dogs Blood Fat Fraction

What types of fat are circulating in your dog's blood and what's their purpose? Dogs Blood Fat Fraction takes a deeper look at the fat fractions implicated in canine hyperlipidemia and the lipoprotein structures used to transport them. Elevated triglyceride and cholesterol concentrations are closely tied to the lipoprotein classes that transport them through plasma, so increased levels of certain lipoproteins provide important clues as to the cause of the lipid abnormalities.

Hyperlipidemia in dogs is typically characterized by increased numbers of circulating lipoproteins, which can be the result of increased internal fat production, reduced clearance of fat, or a combination of the two. But while high triglyceride levels often result in a number of complications, dogs are virtually immune to the problems associated with high cholesterol unless their cholesterol levels are severely elevated. The reason lies in their lipoprotein composition and distribution and their unique HDL metabolism.

Treatment of Hyperlipidemia in Dogs

Not all cases of hyperlipidemia in dogs require treatment. Mild cases of hypertriglyceridemia and mild to moderate cases of hypercholesterolemia are generally not treated, although it is a good idea to keep an eye on serum lipid concentrations. In cases of secondary hyperlipidemia, treatment must focus on the underlying disorder, as successful treatment of the condition responsible will usually resolve the lipid abnormalities.

In cases of primary hyperlipidemia or where secondary hyperlipidemia persists despite treatment of the underlying disorder, a diet low in fat and moderately high in quality protein is recommended as the first line of defense. If such a diet fails to lower serum lipid levels sufficiently, a very low fat diet may be indicated. Your veterinarian may also prescribe supplements or medications. For a detailed overview of the dietary and non-dietary treatment options, see Treatment of Hyperlipidemia.