Descriptions of Lipid Disorders
Lipid Disorders Treated in the Department
Hypercholesterolemia (high cholesterol)
Elevated total cholesterol is most commonly a problem in patients who have elevated LDL cholesterol levels. (Sometimes elevated total cholesterol are associated with elevated levels of good cholesterol, and under this circumstance the total cholesterol is not a very good predictor of heart disease risks). The highest LDL cholesterol levels are seen in patients who have a genetic form of high cholesterol called familial heterozygous hypercholesterolemia (FHH). Patients with FHH do not respond adequately to diet and exercise and often require combinations of medications (e.g. statin plus resin or ezetimibe plus niacin) to bring their LDL cholesterol levels into an acceptable range. Moderate elevations of LDL cholesterol are more common. These moderate elevations are still associated with heart disease risk. There are well established standards for what the targets of LDL cholesterol should be based on risk adjustment profiles. For example, young people with no heart disease risk factors have higher LDL cholesterol targets than patients who have diabetes or established heart disease. Adjusting LDL targets is part of the management strategy addressed with each patient who comes to visit the Clinic.
Hypertriglyceridemia is associated with increased heart disease risk. Hypertriglyceridemia is commonly associated with obesity and diabetes mellitus. There are also familial forms not associated with these disorders. Very high triglycerides are also associated with a risk for pancreatitis (inflammation of the pancreas, a gland in the abdomen) as well as non-specific abdominal pain and sometimes a bumpy yellowish skin rash (called eruptive xanthomata). Dietary intervention is the first step in treating all patients with elevated triglycerides. Use of medications (e.g. fibrates, niacin, fish oils) is often necessary. The medications used for treating triglycerides are often different than those used to lower LDL cholesterol. Treatment of contributors to high triglycerides including reduction in body weight and the management of diabetes mellitus are also important. Some medications used to lower blood sugar will also have a favorable effect on triglycerides. Endocrinologists have much experience with these triglyceride-related conditions.
Mixed Dyslipidemias or Hyperlipidemias
Mixed hyperlipidemias are a combination of elevated LDL cholesterol, elevated triglycerides and low HDL cholesterol (good cholesterol). As with other abnormalities of cholesterol and triglycerides, there is often a genetic or familial component. Mixed hyperlipidemias contribute to heart disease risk. As with hypertriglyceridemia, mixed hyperlipidemias are commonly associated with obesity and diabetes mellitus. Dietary and medication therapies are again important in the management of the mixed hyperlipidemias. Combinations of medications are also usually necessary in patients who have mixed hyperlipidemias.
Low HDL (low good cholesterol)
Isolated low cholesterol, low HDL cholesterol is quite uncommon. Most of the time low HDL cholesterol is associated with high triglycerides. It is well known that low HDL cholesterol contributes to heart disease risk. Exercise is important in helping to raise HDL cholesterol. Medications such as Niacin may also be beneficial in raising HDL cholesterol. In patients who have associated elevations of triglycerides, the triglyceride lowering medications often will raise HDL cholesterol at the same time.
Metabolic Syndrome and Associated Dyslipidemias
The metabolic syndrome is a term to describe patients who have central obesity, elevations of blood sugar (including diabetes), elevations in blood pressure as well as a lipid disorder characterized as high triglycerides, low HDL (and often mildly elevated LDL). Most commonly in the endocrinology clinics we see the metabolic syndrome associated with patients who have diabetes mellitus.