What Is Hyperlipidemia

What Is Hyperlipidemia? Cholesterol is a type of lipid--an essential element contained in all human cells. However, excess lipids and other fatty substances in the blood can cause hyperlipidemia and other lipid disorders. Hyperlipidemia is a significant risk factor for development of atherosclerosis and heart disease.

A Healthy Cardiovascular System The cardiovascular system comprises the heart, blood vessels, and blood. Blood has many lifesustaining responsibilities, including transporting oxygen, carbon dioxide, nutrients, and hormones throughout the body. Blood contains red blood cells, white blood cells, platelets, and nutrients. Cholesterol also circulates in the blood stream. Two common forms of cholesterol are LDL, known as the 'bad cholesterol' and HDL, known as the 'good cholesterol.' Hyperlipidemia is the term used when the blood contains a higher amount of LDL than is recommended.

Effects of Hyperlipidemia Cholesterol and other fatty substances combine in the bloodstream and are deposited in the blood vessels to form a material called plaque. The increase in lipids can cause plaques to grow over time, leading to obstructions in blood flow. If an obstruction occurs in the coronary arteries, it could result in a heart attack. And, if an obstruction occurs in the arteries of the brain, it could lead to stroke.

Causes of Hyperlipidemia Causes of hyperlipidemia can include heredity and taking certain medications. However, the greatest, modifiable risk factor is diet; a poor diet is one with a fat intake greater than 40 percent of total calories, saturated fat intake greater than 10 percent of total calories; and cholesterol intake greater than 300 milligrams per day.

Symptoms of Hyperlipidemia There are no symptoms of hyperlipidemia, so regular cholesterol screening with blood tests should be part of the physical examination. A doctor or healthcare professional can recommend ways to prevent hyperlipidemia.

An excess of fats or lipids in the blood. Also called hyperlipemia.

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Top Dental Dictionary: hyperlipidemia Top Home > Library > Health > Dental Dictionary n An excess of lipids in the plasma, including the glycolipids, lipoproteins, and phospholipids. Veterinary Dictionary: hyperlipidemia Top

Home > Library > Animal Life > Veterinary Dictionary A general term for elevated concentrations of any or all of the lipids in the plasma. See also hyperlipoproteinemia. • • •

postprandial h. — a normal increase following ingestion of food. primary h. — caused by decreased activity of lipoprotein lipase, it occurs in miniature Schnauzer dogs. secondary h. — may occur in association with diabetes mellitus, hypothyroidism, pancreatitis, hyperadrenocorticism, cholestatic liver disease and nephrotic syndrome.

Wikipedia: Hyperlipidemia Top Home > Library > Miscellaneous > Wikipedia Hyperlipidemia Classification and external resources ICD-10 E78. ICD-9 272.0-272.4 DiseasesDB 6255 MeSH D006949

Hyperlipidemia, hyperlipoproteinemia or dyslipidemia is the presence of raised or abnormal levels of lipids and/or lipoproteins in the blood. Lipids (fatty molecules) are transported in a protein capsule, and the density of the lipids and type of protein determines the fate of the particle and its influence on metabolism. Lipid and lipoprotein abnormalities are extremely common in the general population, and are regarded as a highly modifiable risk factor for cardiovascular disease due to the influence of cholesterol, one of the most clinically relevant lipid substances, on atherosclerosis. In addition, some forms may predispose to acute pancreatitis.

Contents [hide] •

1 Classification o 1.1 Hyperlipoproteinemia type I o 1.2 Hyperlipoproteinemia type II  1.2.1 Type IIa  1.2.2 Type IIb  1.2.3 Treatment o 1.3 Hyperlipoproteinemia type III

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1.4 Hyperlipoproteinemia type IV (type 4 = familial) 1.5 Hyperlipoproteinemia type V (type 5 = endogenous) 2 Unclassified forms 3 References

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4 External links

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Classification Hyperlipidemias are classified according to the Fredrickson classification which is based on the pattern of lipoproteins on electrophoresis or ultracentrifugation.[1] It was later adopted by the World Health Organization (WHO). It does not directly account for HDL, and it does not distinguish among the different genes that may be partially responsible for some of these conditions. It remains a popular system of classification, but is considered dated by many. Fredrickson classification of Hyperlipidemias Hyperlipoproteinemi a

Synonyms

Type I

Buerger-Gruetz syndrome, Primary hyperlipoproteinaemia , or Familial hyperchylomicronemia

Type IIa

Problems

Polygenic LDL hypercholesterolaemia Elevated receptor or Familial LDL only deficiency hypercholesterolemia Decreased LDL receptor and Increased ApoB

Type IIb

Type III

Familial Defect in Dysbetalipoproteinemi ApoE a synthesis Familial Hyperlipemia

Treatment

Decreased lipoprotein Elevated lipase Chylomicron Diet Control (LPL) or s altered ApoC2

Combined hyperlipidemia

Type IV

Labs description

Bile Acid Sequestrants, Statins, Niacin

Elevated Statins, LDL and Niacin, VLDL and Fibrate Triglycerides

Increased IDL

Drug of choice: Fibrate

Increased Increased VLDL VLDL production

Drug of choice: Fibrate,

Type V

Endogenous Hypertriglyceridemia

and Decreased eliminatio n

Niacin

Increased VLDL production and Decreased LPL

Increased VLDL and Niacin, Chylomicron Fibrate s

Hyperlipoproteinemia type I This very rare form (also known as Buerger-Gruetz syndrome, primary hyperlipoproteinaemia, or familial hyperchylomicronemia) is due to a deficiency of lipoprotein lipase (LPL) or altered apolipoprotein C2, resulting in elevated chylomicrons, the particles that transfer fatty acids from the digestive tract to the liver. Lipoprotein lipase is also responsible for the initial breakdown of endogenously made triacylglycerides in the form of very low density lipoprotein (VLDL). As such, one would expect a defect in LPL to also result in elevated VLDL. Its prevalence is 0.1% of the population.

Hyperlipoproteinemia type II Hyperlipoproteinemia type II, by far the most common form, is further classified into type IIa and type IIb, depending mainly on whether there is elevation in the triglyceride level in addition to LDL cholesterol. Type IIa Main article: Familial hypercholesterolemia This may be sporadic (due to dietary factors), polygenic, or truly familial as a result of a mutation either in the LDL receptor gene on chromosome 19 (0.2% of the population) or the ApoB gene (0.2%). The familial form is characterized by tendon xanthoma, xanthelasma and premature cardiovascular disease. The incidence of this disease is about 1 in 500 for heterozygotes, and 1 in 1,000,000 for homozygotes. Type IIb The high VLDL levels are due to overproduction of substrates, including triglycerides, acetyl CoA, and an increase in B-100 synthesis. They may also be caused by the decreased clearance of LDL. Prevalence in the population is 10%.

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Familial combined hyperlipoproteinemia (FCH) Secondary combined hyperlipoproteinemia (usually in the context of metabolic syndrome, for which it is a diagnostic criterion)

Treatment While dietary modification is the initial approach, many patients require treatment with statins (HMG-CoA reductase inhibitors) to reduce cardiovascular risk. If the triglyceride level is markedly raised, fibrates may be preferable due to their beneficial effects. Combination treatment of statins and fibrates, while highly effective, causes a markedly increased risk of myopathy and rhabdomyolysis and is therefore only done under close supervision. Other agents commonly added to statins are ezetimibe, niacin and bile acid sequestrants. There is some evidence for benefit of plant sterol-containing products and ω3-fatty acids[2]

Hyperlipoproteinemia type III This form is due to high chylomicrons and IDL (intermediate density lipoprotein). Also known as broad beta disease or dysbetalipoproteinemia, the most common cause for this form is the presence of ApoE E2/E2 genotype. It is due to cholesterol-rich VLDL (βVLDL). Prevalence is 0.02% of the population.

Hyperlipoproteinemia type IV (type 4 = familial) This form is due to high triglycerides. It is also known as hypertriglyceridemia (or pure hypertriglyceridemia). According to the NCEP-ATPIII definition of high triglycerides (>200 mg/dl), prevalence is about 16% of adult population.[3]

Hyperlipoproteinemia type V (type 5 = endogenous) This type is very similar to type I, but with high VLDL in addition to chylomicrons. It is also associated with glucose intolerance and hyperuricemia

Unclassified forms Non-classified forms are extremely rare: • •

Hypo-alpha lipoproteinemia Hypo-beta lipoproteinemia (prevalence 0.01-0.1%)

References 1. ^ Frederickson DS, Lee RS. A system for phenotyping hyperlipidemia. Circulation 1965;31:321-7. PMID 14262568.

2. ^ Thompson GR. Management of dyslipidaemia. Heart 2004;90:949-55. PMID 15253984. 3. ^ Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) Final Report. Circulation 2002; 106; page 3240

External links • •

The Fredrickson papers (with photos from early lipoprotein research) 745209914 at GPnotebook

Hyperlipoproteinemia

OMIM

GPnotebook

Type I

Online 'Mendelian Inheritance in Man' (OMIM) 238600

-1389035478 at GPnotebook

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-1664090094 at GPnotebook

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-1375338454 at GPnotebook

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Type IIa

WebMD

Others MeritCare

Type IIb

Online 'Mendelian Inheritance in Man' (OMIM) 144400

Type III

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630849560 at GPnotebook

WebMD

Yahoo

Type IV

Online 'Mendelian Inheritance in Man' (OMIM) 144600

-1362100182 at GPnotebook

WebMD

Yahoo

Type V

Online 'Mendelian Inheritance in Man' (OMIM) 144600

-1355481046 at GPnotebook

Merck

Definition of Hyperlipidemia Article updated and reviewed by Hubert Chen, MD, Associate Director of Medical Sciences, Amgen Inc. and Assistant Professor of Clinical Medicine University of California, San Francisco on May 17, 2005.

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. This is the only way that these fatty substances can remain dissolved while in circulation. Hyperlipidemia, in general, can be divided into two subcategories:

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hypercholesterolemia, in which there is a high level of cholesterol hypertriglyceridemia, in which there is a high level of triglycerides, the most common form of fat

Description of Hyperlipidemia The fat-protein complexes in the blood are called lipoproteins. The best-known lipoproteins are LDL (low density lipoprotein) and HDL (high density lipoprotein). Excess LDL cholesterol contributes to the blockage of arteries, which eventually leads to heart attack. Population studies have clearly shown that the higher the level of LDL cholesterol, the greater the risk of heart disease. This is true in men and women, in different racial and ethnic groups, and in all adult age groups. Hence, LDL cholesterol has been labeled the “bad” cholesterol. In contrast, the lower the level of HDL cholesterol, the greater the risk of coronary heart disease. As a result, HDL cholesterol is commonly referred to as the “good” cholesterol. Low HDL cholesterol levels are typically accompanied by an increase in blood triglyceride levels. Studies have shown that high triglyceride levels are associated with an increased risk of coronary heart disease.

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Causes and Risk Factors of Hyperlipidemia Common secondary causes of hypercholesterolemia (specifically, high LDL cholesterol) include hypothyroidism (that is, low thyroid hormone levels), pregnancy, and kidney failure. Common secondary causes of hypertriglyceridemia include diabetes, excess alcohol intake, obesity, and certain prescription medications (such as glucocorticoids and estrogen). Hyperlipidemia, along with diabetes, hypertension (high blood pressure), positive family history, and smoking are all major risk factors for coronary heart disease.

Symptoms of Hyperlipidemia Hyperlipidemia usually has no noticeable symptoms and tends to be discovered during routine examination or evaluation for atherosclerotic cardiovascular disease. However, deposits of cholesterol (known as xanthomas) may form under the skin (especially around the eyes or along the Achilles tendon) in individuals with familial forms of the disorder or in those with very high levels of cholesterol in the blood. Individuals with hypertriglyceridemia may develop numerous pimple-like lesions

across their body. Extremely high levels of triglycerides may also result in pancreatitis, a severe inflammation of the pancreas that may be life-threatening.

Diagnosis of Hyperlipidemia Diagnosis is typically based on medical history, physical examination, and blood tests (done after overnight fasting) in order to determine the specific levels of LDL cholesterol, HDL cholesterol, and triglycerides.

Treatment of Hyperlipidemia It is necessary to first identify and treat any potential underlying medical problems, such as diabetes or hypothyroidism, that may contribute to hyperlipidemia. Treatment of hyperlipidemia itself includes dietary changes, weight reduction and exercise. If lifestyle modifications cannot bring about optimal lipid levels, then medications may be necessary. Current national guidelines suggest a LDL cholesterol goal of <100 mg/dl for individuals already with heart disease or diabetes, <130 mg/dl for those with moderate risk of heart disease, and <160 mg/dl for everyone else. Your doctor can calculate your “risk score” for heart disease. This score can then be used to determine whether you need to start taking medications to lower your LDL cholesterol. Although there are no firm treatment targets for HDL cholesterol or triglycerides, most experts agree that optimal HDL cholesterol and triglyceride levels are >40 mg/dl and <200 mg/dl, respectively. Medications most commonly used to treat high LDL cholesterol levels are statins, such as atorvastatin (Lipitor) or simvastatin (Mevacor). These medications work by reducing the production of cholesterol within the body. Although safe and effective, statins very rarely cause muscle damage, typically when used in combination with other medications. Thus, it is important to let your doctor know whether you develop any generalized body ache or start a new medication when you are taking statins. Other medications used to treat high LDL cholesterol levels include ezetimibe (Zetia), which decreases the absorption of cholesterol from the gut; bile-acid sequestrants (Questran), which eliminate cholesterol from the body; and nicotinic acid (Niacin), which, in addition to lowering LDL cholesterol, raises HDL cholesterol. Hypertriglyceridemia is typically treated with a class of medications called fibrates. Included in this class are gemfibrozil (Lopid) and fenofibrate (Tricor). Similar to statins, fibrates are safe and effective but may cause muscle damage, usually when used in combination with other medications.