Hyperlipidemia

What is hyperlipidemia?

Hyperlipidemia refers to elevated levels of lipids (fats) in the bloodstream. The term is typically used to refer to elevated levels of triglycerides or cholesterol.

What causes hyperlipidemia?

There are several possible causes of hyperlipidemia.

• Postprandial hyperlipidemia. Serum triglyceride levels are often increased for 6-12 hours after a meal, especially if your pet is eating a high-fat diet. If a post-meal sample shows elevated triglyceride levels, the test should be repeated after a 12-18 hour fast to see whether this finding is truly cause for concern.
• Medication-induced hyperlipidemia. Certain medications, such as steroids, can alter the body’s metabolism and lead to hyperlipidemia.
• Hereditary hyperlipidemia. Elevated triglyceride and/or cholesterol levels can have genetic causes. Hereditary hyperlipidemia is most common in Miniature Schnauzers, Shetland Sheepdogs, Beagles and Collies, though other breeds can also be affected. Some affected dogs show clinical signs of illness, while others are asymptomatic.
• Secondary or acquired hyperlipidemia. Elevated lipid levels are often a response to another disease process in the body. Conditions such as diabetes mellitus, hypothyroidism, Cushing’s disease, pancreatitis, and certain kidney diseases can affect the body’s metabolism and contribute to hyperlipidemia.

What are the clinical signs of hyperlipidemia?

In most cases, hyperlipidemia has no clinical signs. The condition is often detected only when a veterinarian performs routine screening bloodwork.

"In most cases, hyperlipidemia has no clinical signs."

If clinical signs do occur, they are often gastrointestinal signs. Affected pets may develop vomiting, diarrhea, decreased appetite, and potentially pancreatitis. Additionally, excess lipids may deposit on the cornea (leading to white patches on the surface of the eye) or within the eye (leading to inflammation of the eye and/or blindness). Some pets develop skin abnormalities, such as itching and hair loss. Extremely high triglyceride levels can lead to seizures and behavioral changes, although these effects are uncommon.

My pet’s bloodwork shows hyperlipidemia. What will my veterinarian do next?

First, your veterinarian will confirm that the abnormal results came from a fasting sample. If your pet ate in the 12 hours prior to the blood draw, your veterinarian will likely recommend repeating the test on a blood sample collected after a 12-hour or 18-hour fast. If hyperlipidemia persists even on a fasted sample, further testing is required.

Your pet’s medical history will be reviewed thoroughly. Some medications (especially corticosteroids, such as prednisone) and progestogens can cause elevated lipid levels. If your pet is on any of these medications, your veterinarian may choose to discontinue to the medication or may continue the medication while monitoring your pet’s bloodwork.

Your veterinarian will evaluate your pet’s history and physical exam findings to look for evidence of underlying conditions that could cause hyperlipidemia (e.g., diabetes mellitus, hypothyroidism, Cushing’s disease, or pancreatitis). If any of these conditions are suspected, your veterinarian will perform additional testing to diagnose or rule out these conditions.

If no other cause is identified, your veterinarian may suspect hereditary hyperlipidemia. Further testing can be performed to diagnose and characterize this abnormality.

How will my veterinarian treat my pet’s hyperlipidemia?

If your veterinarian identifies an underlying cause for the hyperlipidemia, this cause will be treated (if possible). Your pet may receive medications for Cushing’s disease or hypothyroidism, insulin injections for diabetes, or treatment for pancreatitis.

If no underlying cause is found, your pet will need to start eating a low-fat, high-fiber diet. Prescription foods are typically used, although you may be able to work with a veterinary nutritionist to formulate a home-cooked diet if you would prefer. Within 1-2 months, this diet change should lead to a reduction in hyperlipidemia.

In addition to diet changes, medications and supplements may also be recommended. Omega-3 fatty acids (fish oil) and/or chitin/chitosan can help resolve hyperlipidemia, when combined with a low-fat diet. Human drugs that are used to decrease triglyceride and cholesterol levels in pets include gemfibrozil (brand name: Lopid®), bezafibrate (brand name: Bezalip®), fenofibrate (brand names: Tricor®, Triglide®), and statins, such as atorvastatin (brand name: Lipitor®) and lovastatin (brand names: Altocor®, Mevacor®). These drugs have not been tested extensively in dogs and cats however, and therefore dietary management is preferred when possible.