ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in medical reports or on incapacity certificates. E78ArtikelübersichtHypercholesterinämie
- Causes and risk factors
- Examinations and diagnosis
- Disease course and prognosis
Hypercholesterolemia is a disorder of lipid metabolism in the body. Here, the amount of cholesterol in the blood is increased. Cholesterol (cholesterol) is a vital natural product of animal cells. It is extremely important for the construction of the cell membrane. In addition, cholesterol is required for the production of bile acids for digestion of fat in the intestine and for the synthesis of sex hormones (testosterone, estradiol, progesterone). The stress hormone cortisol and the messenger aldosterone (water and salt balance) are also formed from cholesterol.
Only a small portion of cholesterol is taken up with food. A much larger proportion is produced by the body itself, mainly in the liver and intestinal mucosa. This process is called cholesterol biosynthesis. This forms as an intermediate 7-dehydrocholesterol. This substance is the precursor to vital vitamin D.
Normally, the total blood cholesterol is below 200 milligrams of cholesterol per deciliter. Slightly elevated cholesterol levels (200-239 mg / dl) are considered medically borderline. Increasing levels are too high a cholesterol level, ie hypercholesterolemia.
Cholesterol is only about 30 percent free in the human body. The remaining 70 percent are associated with fatty acids (cholesterol esters). As a fat-like substance, cholesterol is water-insoluble. However, in order to be transported in the blood, it must become water-soluble. In addition, cholesterol and cholesterol esters combine with other substances. Together with lipids (fats: triglycerides, phospholipids) and proteins (apoproteins) it forms fat-protein complexes called lipoproteins.
Depending on the composition, a distinction is made between different lipoproteins. Among the most important are chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL). In addition, there is IDL (intermediate density lipoproteins), which stands between LDL and VLDL, and the lipoprotein a, which is similar in structure to the LDL.
Chylomicrons transport dietary fats (triglyceride content 85 percent) from the intestine into the body. VLDL in turn consists mainly of triglycerides that are produced in the liver. This lipoprotein is eventually converted to IDL and LDL. It loses its fats, whereas the cholesterol increases.
In hypercholesterolemia, the lipoproteins LDL and HDL play a crucial role. They consist mostly of cholesterol and keep the cholesterol balance. LDL transports cholesterol from the liver via the blood to the remaining body cells. Increased LDL also means increased cholesterol levels up to hypercholesterolemia. As a result, the cholesterol deposits in the blood vessels and leads to arteriosclerosis (plaques, "vascular calcification"). This is counteracted by the lipoprotein HDL. It transports excess cholesterol back to the liver, preventing increased cholesterol levels.
Therefore, LDL is also known as "bad" and HDL as "good cholesterol".
Hypercholesterolemia as a group of lipid metabolism disorders
Hypercholesterolemia is the result of a disorder in fat metabolism and is associated with elevated cholesterol levels. Lipid metabolism disorders are also referred to as hyperlipoproteinemia, hyperlipidemia or dyslipidemia. In addition to hypercholesterolemia also includes the hypertriglyceridemia. In addition, there is a combined hyperlipidemia. Patients have a high cholesterol and high triglyceride fats in the blood.To the table of contents
Hypercholesterolemia, which means elevated cholesterol levels in the blood, does not cause any discomfort. Rather, hypercholesterolemia is a sign of other diseases. In the long run, however, high blood cholesterol can have serious consequences.
The distribution of cholesterol in the body is due to LDL, which is typically elevated with hypercholesterolemia. If the HDL lipoproteins are reduced, the cholesterol return transport to the liver is disturbed. The result is hypercholesterolemia. The excess cholesterol deposits in the vessel walls. Then a process is set in motion, which ultimately harms the vessels (arteries = arteries). With cholesterol, fats, carbohydrates, blood components, fibrous tissue and lime enter the vessel wall. Hypercholesterolemia thus leads to arteriosclerosis, popularly known as vascular calcification.
CHD and heart attack
In vascular calcification, the arteries are increasingly narrowed. If the heart disease is affected, doctors talk about coronary heart disease (CHD). In this way, hypercholesterolemia can also lead to heart attack. Thus, the risk of heart attack is approximately doubled with a total cholesterol level (HDL plus LDL) of 250 mg / dl. With a total value of over 300 mg / dl, it is four times as high as in people with normal cholesterol levels. The coronary arteries are sometimes almost completely closed and the heart muscle can not be properly supplied with oxygen. Affected persons complain of a feeling of pressure or pain in the chest. Tachycardia, dizziness, sweats and shortness of breath are also signs of heart attack.
PAD and stroke
If the arteries of the legs are damaged by hypercholesterolemia, it can lead to intermittent claudication. Physicians speak of a PAD (peripheral arterial disease). Patients suffer from painful circulatory disorders, especially under stress (e.g., walking). If the neck and cerebral arteries are narrowed due to hypercholesterolemia, an oxygen deficiency in the brain may occur. Threatening short-term (TIA = transient ischemic attack) neurological deficits such as hemiplegia to stroke (ischemic cerebral infarction).
Xathomas are fatty deposits in the tissue, especially in the skin. Due to hypercholesterolemia, but also due to hypertriglyceridemia, fats and cholesterol, for example, accumulate on the trunk or on the hands and form yellowish-yellow thickened skin (plane xanthomas). If there is an increase in cholesterol in the eyelids, doctors talk about xanthelasma.
Larger skin thickenings of yellow-brownish color on elbows or knees are called tuberous xanthomas. Xanthomas on the finger or Achilles tendon are also symptoms of hypercholesterolemia. Also typical of hypertriglyceridemia are yellowish nodules on reddened skin, in particular on the buttocks and the extensor sides of the arms and legs. Medically, these skin manifestations are called eruptive xanthomas. Fat deposits on the lines of the hand usually indicate an increase in IDL and VLDL.
Hypercholesterolemia on the eye
High cholesterol may also be deposited in the cornea of the eyes. There, a visible turbidity ring of gray-white color forms at the edge of the cornea. Doctors in this case speak of an arcus (lipoides) corneae. This lipid ring is common in the elderly and is considered harmless. In adults less than 45 years, however, it is a clear indication of hypercholesterolemia.To the table of contents
Hypercholesterolemia: causes and risk factors
Hypercholesterolemia is more of a symptom than a pure disease. This also applies to other hyperlipidemias. Mostly they are the consequence of another illness or lifestyle. Depending on the cause of hypercholesterolemia, three groups are distinguished.
Reactive physiological form
For example, a high-cholesterol diet falls into this group. In response, fat metabolism in the human body is overloaded. Increased intake of cholesterol can not be eliminated fast enough and causes high cholesterol in the blood. Alcohol can also lead to hypercholesterolemia, especially with increased IDL in the blood ... In the reactive-physiological form, however, elevated cholesterol levels are only temporary. After a short time, the values normalize again.
In the secondary form of hypercholesterolemia, other diseases cause high cholesterol levels. These include, for example, the diabetes mellitus diabetes. LDL is normally taken up by certain recipient structures (LDL receptors) of the body cells. The high cholesterol level in the blood decreases as a result. This particular LDL intake is delayed in Type 1 diabetes because it lacks insulin. The cholesterol therefore remains in the blood and the patient gets hypercholesterolemia. Obesity (adiposity) increases the production of LDL cholesterol. In addition, insulin does not work properly (insulin resistance, type 2 diabetes). Fatty acids are more likely to enter the liver, increasing VLDL (hypertriglyceridemia).
Thyroid hypofunction (hypothyroidism) can also lead to hypercholesterolemia. In hypothyroidism, the messenger substances of the thyroid are reduced. However, they significantly influence the metabolic processes in the body. With low thyroid hormones, for example, fewer LDL receptors are formed, which ultimately leads to an increased cholesterol level.
Nephrotic syndrome and cholestasis
The nephrotic syndrome arises due to damage to the kidneys. Typically there are increased protein levels in the urine (proteinuria), decreased protein in the blood (hypoproteinemia, hypoalbuminemia) and water retention in the tissue (edema). But hypercholesterolemia and triglyceridemia are also classic signs of nephrotic syndrome. The "good" HDL cholesterol is often reduced. Furthermore, congestion of bile in the bile ducts (cholestasis) leads to increased lipoprotein levels and thus to hypercholesterolemia.
Many medications can also adversely affect lipid metabolism. Most cortisone preparations lead to hypercholesterolemia. Treatments with estrogens, the pill, water tablets (thiazides) or beta-blockers usually increase the triglycerides in the blood. Furthermore, high cholesterol levels were observed in pregnant women. In this case, however, the hypercholesterolemia hardly has a disease value.
Here one speaks of a familial or hereditary (hereditary) hypercholesterolemia. The cause of high cholesterol levels lies in a defect of the genome. Experts distinguish a polygenetic from a monogental hypercholesterolemia. In polygenic hypercholesterolemia, multiple defects in the building blocks of the human genome (genes) lead to slightly elevated cholesterol levels. External factors such as poor nutrition and physical inactivity are usually added.
Familial monogenic hypercholesterolemia
In monogenetic hypercholesterolemia, the defect is solely in the gene containing the information for the production of LDL receptors. They are used to eliminate LDL cholesterol from the blood. In monogenetic familial hypercholesterolemia, these receptors or their function are either completely lacking (homozygous carriers) or the receptors are less active (heterozygous carriers). Affected without a healthy gene (homozygotes) have already in childhood or adolescence first signs of illness. Heterozygotes have a sick as well as healthy gene and suffer mostly in middle age first heart attacks, provided their hypercholesterolemia is not treated. Familial hypercholesterolemia can be inherited (autosomal dominant inheritance).
Hypercholesterolemia by various apolipoproteins
Another genetic defect may involve the apolipoprotein B100. This protein is involved in the construction of LDL and helps in the absorption of LDL cholesterol into the cell. More specifically, it accomplishes the binding of LDL to its receptor. If the function of the apolipoprotein B100 is disturbed, more cholesterol remains in the blood. This hypercholesterolemia can also be inherited (autosomal dominant). In addition to the apolipoprotein B100, there are also various apolipoprotein E forms. Medicine has found that hypercholesterolemia occurs mainly in humans with the apolipoprotein E 3/4 and E 4/4. You also have a higher risk of Alzheimer's disease.
Hypercholesterolemia by PCSK9
PCSK9 (Proprotein Convertase Subtilisin / Kexin Type 9) is an endogenous protein (enzyme) found predominantly in liver cells. This enzyme binds LDL receptors, whereupon they are degraded. As a result, the liver cells can "fish out" less cholesterol from the blood. It comes to hypercholesterolemia. Studies have shown that certain defects in the genome (mutations) of the enzyme increase its effect (gain-of-function). As a result, high cholesterol levels continue to rise. However, cases have also been described in which PCSK9 has lost its function through mutations (loss-of-function), which reduces the risk of hypercholesterolemia.
Other hereditary dyslipidemias
Other disorders of lipid metabolism may also be due to genetic defects. Patients also have elevated cholesterol levels in their blood:
Familial combined hyperlipoproteinemia
Familial hypoalpha lipoproteinemia
In addition, the lipoprotein a may be increased. It is composed of LDL and apolipoprotein a. It inhibits inter alia processes in the blood clotting, especially in the dissolution of blood clots (plasminogen competitor). This speeds up vascular calcification (blood clots are involved in plaque formation in the vessel walls). With LDL hypercholesterolemia, lipoprotein a also increases the risk of cardiovascular diseases.To the table of contents
Hypercholesterolemia: diagnosis and examination
Hypercholesterolemia is detected by a blood test. In many cases, the elevated cholesterol levels are coincidental. You can have your cholesterol levels determined by your family doctor or a specialist in internal medicine (internist). For this he takes blood samples. This blood collection should be done on a fasting basis, ideally after a 12-hour fast (especially important for triglycerides). Subsequently, the blood is analyzed in the laboratory for triglycerides, LDL and HDL as well as total cholesterol and possibly also lipoprotein a. If the values are increased, blood is taken again, this time after food intake. For healthy adults without risk factors for vascular calcifications, the following guidelines apply:
<160 mg / dl
> 35-40 mg / dl
<150-200 mg / dl
Lipoprotein a (Lp a)
<30 mg / dl
If hypercholesterolemia has been detected at the time of blood collection, the physician will check the values after about four weeks. Furthermore, he can determine the "arteriosclerosis risk index" based on the LDL and HDL cholesterol levels. For this purpose, the LDL value is divided by the HDL value (LDL / HDL quotient). A result below two means a low, and over four mean a high risk of vascular damage.
Since hypercholesterolemia is a symptom, doctors need to make a more accurate diagnosis. For this purpose, the German Society of Fat Science has published a scheme with which hypercholesterolemias can be assigned to a disease.
LDL cholesterol blood level
Family history of coronary heart disease (CHD)
> 220 mg / dl
190-220 mg / dl
Familial combined hyperlipidemia (especially with elevated triglycerides)
160-190 mg / dl
Familial combined hyperlipidemia (especially with elevated triglycerides)
Pure diet-related hypercholesterolemia
Medical history (anamnesis)
The medical history (history) is crucial for hypercholesterolemia. It provides the physician with information on possible causes and risk factors. The doctor will ask you about your eating habits and alcohol or cigarette consumption. Also tell the doctor about known illnesses that you suffer from, such as diabetes, thyroid or liver disease. Among other things, the doctor could ask the following questions: