Hyperlipidemia

Definition

Hyperlipidemia is an excess of fatty substances called lipids, largely cholesterol and triglycerides, in the blood. It is also called hyperlipoproteinemia, because these fatty substances travel in the blood attached to proteins.

A subcategory of hyperlipidemia is hypercholesterolemia, in which there is a high level of total cholesterol.

Description

The fat-protein complexes in the blood are called lipoproteins. The best known lipoproteins are HDL (high density lipoprotein), LDL (low density lipoprotein), and VLDL (very low density lipoprotein).

Epidemiologic studies have clearly shown that the higher the level of LDL cholesterol, the greater the risk of coronary heart disease. Conversely, the higher the level of HDL cholesterol, the lower the risk of coronary heart disease. This is true in men and women, in different racial and ethnic groups, and at all adult ages.

Types

Hyperlipoproteinemia is the name for at least five distinct metabolic disorders, all of which may be inherited. Some forms are mild, producing symptoms that can be cured by diet, while others are potentially fatal.

Type I causes attacks of severe abdominal pain which usually occur when a person eats fatty foods. It may also cause general discomfort, loss of appetite, and a fever.

Type II causes firm masses on the person's Achilles tendons and the tendons of the hands and feet. The doctor checks for yellow patches or nodules on the skin, an opaque ring surrounding the cornea, and premature coronary artery disease.

Type III can produce soft, inflamed sores over the elbows or knees.

Type IV is linked to overeating, obesity and diabetes.

Type V causes abdominal pain (most common), yellow nodules on the skin, and reddish-white blood vessels in the retinas of the eyes. The doctor checks for an inflamed pancreas, nerve damage, yellow nodules on the arms and legs, and liver problems.

Causes and Risk Factors

Common secondary etiologies of hypercholesterolemia include diabetes mellitus, hypothyroidism, pregnancy, nephrotic syndrome, obstructive jaundice, and chronic renal failure.

Hyperlipidemia, along with diabetes, hypertension (high blood pressure), a positive family history, and smoking are all major risk factors for coronary heart disease.

Symptoms

Hyperlipidemia usually has no overt symptoms and tends to be discovered during routine examination or evaluation for atherosclerotic cardiovascular disease. Pinkish-yellow deposits of fat (known as xanthomas) may develop under the skin (especially around the eyes) in individuals with familial forms of the disorder or in those with very high levels of cholesterol in the blood.

Diagnosis

Diagnosis is based on the medical history, physical examination, and blood tests (typically done after overnight fasting) in order to determine the fraction of each lipoprotein.

Treatment

Evaluation of lipid fractions is essential before therapy for hyperlipidemia is initiated. Treatment may include dietary changes, weight reduction, exercise, and medications.

It is necessary to identify and treat any underlying problem, such as diabetes. If there is no contributing problem, the primary treatment for Types II, III, and IV is often dietary management - namely restricting cholesterol intake.

The most effective treatment for Type V hyperlipoproteinemia is often weight reduction and long-term maintenance of a low-fat diet. Drugs and a special diet may help, but the chance of cure is uncertain because the person with Type V risks developing pancreatitis. Increased fat intake may cause recurrent bouts of illness, possibly leading to the formation of cysts, hemorrhage, and death.

Questions to Ask Your Doctor

How serious is it?

What type of hyperlipidemia is it?

Is there an underlying cause of the hyperlipidemia?

What is its relationship to diabetes?

What treatment do you recommend?

What dietary changes do you recommend?

What weight reduction goals are reasonable?