OVERVIEW
Hyperlipidemia is an abnormally high level of lipoprotein-carrying lipids (cholesterol, triglycerides, etc.) in the blood.
It can be detected without obvious discomfort, during a physical examination or when there are complications.
Hyperlipidemia is associated with genetics, lifestyle, disease, and medications.
Diet, exercise, and medications can help regulate hyperlipidemia
Definition
Lipids is a general term for cholesterol, triglycerides, and lipids in plasma. Hyperlipidemia is an abnormally high level of lipids carried by blood lipoproteins, such as triglycerides (TG) and total cholesterol (TC).
Hyperlipidemia is a manifestation of abnormal lipid metabolism in the body and is clinically classified into three main categories: hypercholesterolemia, hypertriglyceridemia and mixed hyperlipidemia.
Regular lipid screening and active control of risk factors are important measures in the prevention and treatment of hyperlipidemia and cardiovascular diseases.
Typing
Classification according to etiology
Primary hyperlipidemia: related to genetics and lifestyle.
Secondary hyperlipidemia: Hyperlipidemia caused by other diseases or medications.
Clinical classification
According to the different manifestations of blood lipids, hyperlipidemia can be classified as hypercholesterolemia, hypertriglyceridemia, and mixed hyperlipidemia.
Classification Total cholesterol (TC) Triglycerides (TG) High-density lipoprotein cholesterol (HDL-C)
Hypercholesterolemia increased normal normal
Hypercholesterolemia
Increased
Normal
Normal
hypertriglyceridemia normal elevated normal
hypertriglyceridemia
Normal
Increased
Normal
Mixed hyperlipidemia elevated elevated normal
Mixed hyperlipidemia
Increased
Increased
Normal
Prevalence
Hyperlipidemia can be seen in people of different ages and genders, the older the age, the higher the prevalence, and is more common in people aged 50-69 years.
The overall prevalence of dyslipidemia in Chinese adults is as high as 40.40%.
The average value of serum total cholesterol (TC) in adults is 4.5 millimoles per liter (mmol/L), and the prevalence of hypercholesterolemia is 4.9%.
The mean value of triglycerides (TG) is 1.38 mmol/L and the prevalence of hypertriglyceridemia is 13.1%.
Causes
Causes
Genetic factors
Caused by single or multiple gene mutations.
Familial hypercholesterolemia is the result of various mutations in the LDL receptor gene on chromosome 19 that result in either a failure to express the receptor or a receptor deletion.
Familial hypertriglyceridemia is inherited in a variety of ways, most of which are autosomal dominant.
Familial mixed hyperlipidemia is an autosomal dominant condition and may result from multiple mutations.
Environmental factors
These include poor dietary habits, such as high-fat and high-sugar diets, and excessive alcohol consumption.
It may also be associated with inactivity, smoking, etc.
Disease factors
It is a common cause of secondary hyperlipidemia, such as obesity, diabetes mellitus, nephrotic syndrome, and hypothyroidism.
Drug Factors
Certain medications, such as estrogen, birth control pills, glucocorticoids, retinoids and thiazide diuretics, certain antiviral drugs, beta-blockers, and so on.
Others
The incidence of the disease increases in women after menopause, so it is thought that it may be related to the decrease of estrogen.
Pathogenesis
The pathogenesis of primary hyperlipidemia is unknown and may be related to genetic and environmental factors, which together influence the rate of production, utilization, and removal of body fat.
Secondary hyperlipidemia may be caused by disease or medication, which affects the synthesis, transport, or metabolism of lipids or lipoproteins through various mechanisms.
Risk Factors
Patients with close relatives with the disease (family history of the disease).
Overweight.
Foods high in saturated fatty acids and cholesterol.
Too little activity.
Drinking too much alcohol.
Symptoms
Hyperlipidemia is usually asymptomatic and may be detected by physical examination or other diseases (e.g., diabetes mellitus, myocardial infarction, acute pancreatitis, etc.). A small number of people may present with the following manifestations.
Major Symptoms
Yellow Tumor
When blood lipid levels are particularly high, fat can be deposited in the skin and tendons to form lumps.
It appears as an abnormal elevation of the skin, yellow, orange or brownish-red in color and soft in texture.
They are commonly found around the eyelids, in tendon areas, on the extensor side of the body, and in the palms of the hands.
Corneal Arch
Most commonly seen in familial hypercholesterolemia.
Located at the outer edge of the cornea and are gray or white in color.
Complications
The higher the total cholesterol, the higher the risk of atherosclerosis, which can affect the arteries that supply blood to the heart (causing coronary heart disease) and the arteries that supply blood to the brain (causing strokes, etc.); very high triglycerides increase the risk of pancreatitis.
Coronary heart disease
May have angina, which is characterized by a feeling of tightness, swelling, squeezing or pain in the chest that lasts for several minutes or recurs.
Feeling of discomfort in other parts of the upper body, such as pain or discomfort in one or both arms, the back of the shoulder, or the stomach.
Sudden cold sweats, nausea or dizziness.
Stroke.
May include headache, dizziness, numbness and weakness in one limb, sudden blurring of vision or blindness, and inability to speak.
Fatty liver
Mostly found accidentally during a physical examination without symptoms, but may also include lack of appetite, fatigue, nausea, vomiting, abdominal distension, vague pain in the liver area, and enlargement of the liver.
Acute pancreatitis
Acute abdominal pain: often occurs suddenly after a full meal or drinking alcohol, located in the middle-left upper abdomen or even the whole abdomen, can be colicky or cutting pain.
Abdominal distension: often accompanied by abdominal pain.
Nausea and vomiting: Vomiting is often violent and frequent, and the vomit is mainly food, occasionally coffee-colored substances may also be vomited.
Other manifestations: fever, yellowing of the skin and sclera (commonly known as the whites of the eyes).
Consultation
Department of Medicine
Cardiovascular Medicine
Routine physical examination reveals increased blood lipids, or symptoms such as yellow skin tumors, dizziness, headache, chest tightness, etc. It is recommended to consult a doctor promptly.
Preparation for medical treatment
Consultation: Registration, Preparation of Documents, Frequently Asked Questions
Tips for Consultation
Patients with hyperlipidemia have inconspicuous clinical symptoms, which are often detected during physical examination, and need to consult a doctor in time to avoid the development of the disease.
Do not abuse drugs without doctor’s permission, so as to prevent drugs from affecting the relevant examinations and interfering with the diagnosis and treatment of the disease.
Preparation List
Symptom list
Pay special attention to the time of onset of symptoms, special manifestations, etc.
Have you had dizziness or headache recently?
Any other uncomfortable symptoms?
How long have the uncomfortable symptoms lasted? Any triggering factors?
Medical History Checklist
Any relatives with hyperlipidemia?
Have you had a recent physical examination? What were the results of the physical examination?
Are there any other medical conditions?
What is the diet? Is there any greasy diet, overeating?
Do you smoke or drink alcohol?
Checklist
Test results of the last six months, which can be brought to the doctor’s office
Blood test
Blood biochemistry
Lipid Profile
Urine routine
Abdominal ultrasound
Liver and Kidney Function Tests
Thyroid Function Test
Medication List
Medications used in the last 3 months, if available, bring the box or package with you to the doctor’s office.
Statin lipid regulators/lovastatin, simvastatin, atorvastatin
Cholesterol absorption inhibitors: Ezetimibe
Other lipid regulators: Probucol
Betas: Fenofibrate, Benzafibrate, Gemfibrozil
Diagnosis
Diagnosis is based on
Medical history
Family history: first-degree relatives, e.g., whether parents have hyperlipidemia.
History of prior illness: previous diabetes, nephrotic syndrome, obesity, hypothyroidism, etc.
Lifestyle habits: including diet (high-fat, high-calorie diet), lifestyle (low activity), etc.
Clinical manifestations
Most of them are asymptomatic, a few of them may have yellow tumors, dizziness, fatigue, etc.
Laboratory Tests
Lipid test
There are plasma or serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C) and high-density lipoprotein cholesterol (HDL-C), which can find out the level of the above indicators.
It can confirm the diagnosis of hyperlipidemia and test the effectiveness of treatment. The following table shows the expected values of lipid levels in adults.
Precautions: In order to ensure the stability of the test results, the patient should maintain a normal, more constant diet and stable weight for 2 weeks before the test, avoid strenuous exercise for 24 hours before the measurement, start fasting after 8:00 p.m. on the day before the blood collection (a small amount of water is allowed), and collect the blood at 8-10:00 a.m. in the following morning or in the morning.
Lipid target (mmol/L)
Total cholesterol less than 4.4
Total Cholesterol
Below 4.4
Low-density lipoprotein (LDL) cholesterol less than 2.2
Low-density lipoprotein (LDL) cholesterol
Less than 2.2
High-density lipoprotein (HDL) cholesterol above 1.05
High-density lipoprotein (HDL) cholesterol
Above 1.05
Triglycerides below 1.7
Triglycerides
Below 1.7
Other Tests
Including apolipoprotein A (Apo A1), apolipoprotein B (Apo B), and lipoprotein (a) are also clinically significant in predicting coronary artery disease.
Familial dyslipoproteinemia can be genetically diagnosed, and associated genetic abnormalities can be seen.
Diagnostic criteria
The diagnosis of hyperlipidemia is based on the criteria for appropriate levels of lipids and stratification of abnormalities developed in the Chinese Guidelines for the Prevention and Control of Dyslipidemia in Adults (2016 Revision).
Stratification TC (mmol/L) LDL-C (mmol/L) non-HDL-C (mmol/L) TG (mmol/L)
Ideal level/＜2.6＜3.4/
Ideal level
|
/
<2.6
<3.4
Ideal level / ＜2.6＜3.4/
Suitable level <5.2 <3.4 <4.1 <1.7
<4.1
＜1.7
Marginal elevation 5.2～6.193.4～4.094.1～4.891.7～2.29
Marginal elevation
5.2～6.19
3.4～4.09
4.1～4.89
1.7～2.29
Elevation ≥6.2≥4.1≥4.9≥2.3
Elevated
≥6.2
≥4.1
≥4.9
≥2.3
Differential Diagnosis
Hyperlipidemia can be diagnosed on the basis of lipid tests, which need to identify whether it is primary or secondary hyperlipidemia, especially with secondary hyperlipidemia caused by the following diseases.
Hypothyroidism (hypothyroidism)
Similarities: Both have elevated blood lipids.
Differences: Hypothyroidism is characterized by low metabolic symptoms such as fatigue, weight gain, abdominal distension, and slowness of movement. Thyroid function tests for hypothyroidism may show elevated serum thyroid stimulating hormone (TSH) and decreased thyroid hormones (T3, T4). Primary hyperlipidemia is absent.
Cushing’s syndrome
Similarities: both have elevated lipids.
Differences: Cushing’s syndrome may have characteristic manifestations, such as centripetal obesity, purple lines on the skin, increased hairiness, and sexual dysfunction. Primary hyperlipidemia is absent.
Nephrotic syndrome
Similarities: both have elevated lipids.
Differences: Nephrotic syndrome may have massive proteinuria (>3.5 g/day) and hypoalbuminemia (<30 g/l). Primary hyperlipidemia is absent.
Treatment
Principles of treatment
Individualized interventions need to be developed as determined by the degree of risk for atherosclerotic cardiovascular disease. The higher the degree of risk, the more stringent the lipid-modifying therapy.
Dyslipidemia risk stratification
Risk stratification TC 5.18-6.19 or LDL-C 3.37-4.14 (mmol/L) TC ≥ 6.19 or LDL-C ≥ 4.14 (mmol/L)
No hypertension, and other risk factors <3 low risk low risk
No hypertension and other risk factors <3
Low risk
Low risk
Hypertension or other risk factors ≥3 low risk medium risk
High blood pressure or other risk factors ≥3
Low risk
medium risk
High blood pressure and other risk factors ≥1 medium risk high risk
High blood pressure and other risk factors ≥1
Medium Risk
High risk
Coronary heart disease and other risk conditionsHigh riskHigh risk
Coronary heart disease and other risk conditions
High risk
High Risk
Acute Coronary SyndromeVery High RiskVery High Risk
Acute Coronary Syndrome
Very High Risk
Very High Risk
Ischemic cardiovascular disease combined with diabetes mellitus very high risk very high risk
Ischemic cardiovascular disease combined with diabetes mellitus
Very high risk
Very high risk
Note: Other risk factors include age (≥55 years for women and ≥45 years for men), smoking, low HDL cholesterolemia, obesity, and history of early-onset ischemic cardiovascular disease.
Lipid regulation goals
Risk class LDL-C (mmol/L) non-HDL-C (mmol/L)
Low risk, intermediate risk <3.4 <4.1
Low risk, intermediate risk
＜3.4
＜4.1
High risk ＜2.6＜3.4
High risk
<2.6
＜3.4
Very high risk <1.8 <2.6
Very high risk
<1.8
<2.6
Treatment
General treatment
Diet control and lifestyle improvement are the basic measures for treating dyslipidemia. Regardless of whether drug therapy is chosen, lifestyle intervention must be adhered to. It is important to reduce weight if you are overweight; quit smoking if you smoke; and increase activity level.
Diet
Doctors need to formulate recipes according to the degree and type of dyslipidemia of the patient, as well as gender, age and labor intensity.
Reduce the intake of saturated fatty acids and cholesterol, choose foods with polyunsaturated fatty acids, and supplement plant sterols and soluble fiber. Below are the recommended amounts of fat and cholesterol in the diet.
Fat Type Recommended Intake Food Source
Less than 7% to 10% of total calories from saturated fat; less than 7% for patients with high lipid levels or coronary heart disease Meat, unskimmed dairy products (whole milk, cheese), artificially hydrogenated vegetable oils
Saturated fat
Less than 7%-10% of total calories; less than 7% for patients with high lipid levels or coronary heart disease
Meat, non-skimmed dairy products (whole milk, cheese), artificially hydrogenated vegetable oils
Polyunsaturated fats up to 10% of the total calories
Polyunsaturated fat
10% of total calories
Monounsaturated fats up to 20% of total calories Canola oil, olive oil, nuts, avocados
Monounsaturated fat
20% of total calories
Canola oil, olive oil, nuts, avocados
Cholesterol less than 300 mg per day, less than 200 mg per day for patients with hypercholesterolemia or coronary heart disease Egg yolks, animal offal, meat, fish or other seafood, unskimmed milk products