Physician Assistant Exam: The Lipid Panel as a Diagnostic Tool
Lipids are important for the Physician Assistant Exam (PANCE) because any person who goes to see a healthcare provider gets a lipid panel done as part of a comprehensive workup. Most lipid panels show levels for high-density lipoprotein, low-density lipoprotein, triglyceride, and total cholesterol. Author Barry loves reading his own labs, because the computer printout shows the normal range and flags any results that are out of range.
Understanding HDL, LDL, triglyceride, and cholesterol levels is important because of their link with coronary artery disease and association with other conditions like diabetes mellitus:
Diabetes mellitus can be associated with high triglycerides and low HDL levels.
Hypothyroidism, obesity, sedentary lifestyle, and metabolic syndrome all increase the risk of developing hyperlipidemia.
High LDL levels, low HDL levels, and high triglycerides are associated with an increased risk of coronary artery disease.
Very high triglyceride levels (usually > 1,000 mg/dL) and extremely high cholesterol levels are risk factors not only for heart disease but also for pancreatitis.
With newer medical guidelines, just screening for total cholesterol and triglycerides is a no-no. HDL and LDL need to be included.
Heredity and hyperlipidemia
Become familiar with some of the hereditary forms of hyperlipidemia, because they could appear on the PANCE:
Familial hypercholesterolemia (FH) is a hereditary condition in which the affected person can have super-high cholesterol and LDL levels. This condition is thought to be due to a mutation of the LDL receptor (LDLR) gene. FH is inherited in an autosomal dominant fashion, and this disorder has both homozygous and heterozygous forms. People with the homozygous form don’t survive long as adults.
In familial dysbetalipoproteinemia, not only are there increased total cholesterol, LDL, and triglyceride levels, but there are also low HDL levels. Experts think that this condition is due to a defect with apolipoprotein E’s role in catabolism of lipids.
Familial hypertriglyceridemia causes (you guessed it) high triglycerides.
Familial combined hyperlipidemia is just that: Elevated total cholesterol and triglycerides.
Familial hypercholesterolemia and other familial conditions can present with xanthomas, which represent lipid deposition in joints or in tendons. There may be xanthelasmas, which are deposits along the eyelids. You see these deposits only with very high cholesterol levels.
How to treat hyperlipidemia
Certainly, diet and lifestyle changes, including exercising and stopping smoking, are very important in improving lipid health. A diet low in saturated fat and high in fiber can help lower cholesterol. Diet and lifestyle changes can also lower LDL and triglyceride levels and raise HDL levels. Sometimes, though, that may not be enough, and medication is necessary.
The statins, including atorvastatin (Lipitor) and simvastatin (Zocor), are commonly prescribed for the treatment of hyperlipidemia. Side effects of these medications include liver problems and myopathy. Some people have reported problems with memory.
A common class of medication used to treat hypertriglyceridemia (high triglycerides) is the fibrate class. Derivatives include fenofibrate (Tricor). With this med, you need to watch liver enzymes closely. If a patient is on both a statin and fenofibrate, his or her risk of hepatotoxicity increases. Omega-3 (fish oil) has also been used in the treatment of hypertriglyceridemias.
Low HDL levels can be treated with nicotinic acid (niacin). However, liver enzymes may be affected. A common side effect of nicotinic acid is flushing, so to reduce the risk, sometimes aspirin is prescribed before the person takes the medication.
Bile acid sequestrants work in the intestine but have different modes of action. Ezetimibe (Zetia) inhibits the absorption of cholesterol in the intestine. Bile acid resins like cholestyramine (Questran) and colestipol (Colestid) function as bile acid binders in the intestine.