Hypercholesterolemia: Causes, Symptoms, Diagnosis and Treatment

Cholesterol is a lipid substance that is vital for our bodies to function properly. It plays a key role in the formation of cell membranes, the synthesis of steroid hormones, bile, and vitamin D. However, when present in excess, it can lead to serious health complications, primarily cardiovascular diseases.

Types of Cholesterol: LDL and HDL

Cholesterol, being insoluble in water, is transported in the bloodstream by lipoproteins. These molecules consist of a lipid core, rich in cholesterol and other fat-soluble substances, surrounded by a protein and phospholipid shell. They are classified based on their density, which varies inversely with their lipid content. The key types include Very Low-Density Lipoproteins (VLDL), Low-Density Lipoproteins (LDL), Intermediate Density Lipoproteins (IDL), and High-Density Lipoproteins (HDL).

LDL, often referred to as 'bad cholesterol,' transports cholesterol from the liver to the body's periphery, promoting its deposition on arterial vessel walls. On the other hand, HDL, or 'good cholesterol,' carries cholesterol from the body's periphery to the liver, acting like a street cleaner, clearing arteries from cholesterol deposits. It's no surprise that high LDL cholesterol levels are associated with increased cardiovascular risk, while high HDL cholesterol levels correlate with lower cardiovascular risk.

What is Hypercholesterolemia?

Hypercholesterolemia is a medical term used to denote high levels of cholesterol in the blood, it can lead to severe health complications, predominantly cardiovascular diseases.

As previously mentioned the most concerning situation arises when there is a rise in low-density lipoprotein cholesterol (LDL also called "bad cholesterol"). Excessive LDL cholesterol tends to accumulate on the blood vessel walls, forming plaques that obstruct blood flow and harden the arteries. This condition can lead to vascular ischemia, vessel ruptures, and hypertension.

On the other hand, high-density lipoprotein cholesterol (HDL or "good cholesterol"), lowers cardiovascular risk. HDL particles help rid the body of cholesterol by capturing it and transporting it to the liver for elimination.

Causes Influencing Cholesterol Levels

Numerous factors can influence blood cholesterol levels. Here's a detailed look at some of them:

  • Diet: While the influence of nutrition on total cholesterol levels is often overestimated, it still plays a significant role. A diet rich in cholesterol, caloric excesses, and high intake of saturated and hydrogenated fatty acids can contribute to increased cholesterol levels.
  • Thyroid Function: Reduced thyroid activity (hypothyroidism) can increase cholesterol levels, while an excess of thyroid hormones (hyperthyroidism) can decrease it.
  • Hormonal Balance: Estrogens tend to lower cholesterol levels, while androgens increase them. This is why cardiovascular risk is typically higher in men and increases significantly after menopause.
  • Physical Activity: Regular aerobic physical activity can increase HDL cholesterol levels, which is beneficial for heart health.
  • Smoking: Nicotine and other substances from tobacco smoke can stiffen arteries and reduce the anti-sclerotic action of HDL cholesterol, promoting the accumulation of cholesterol plaques.
  • Medication: Prolonged use of certain medications like immunosuppressants, antiretrovirals, cortisonics, oral contraceptives, and anabolic steroids can also contribute to higher cholesterol levels.
  • Pathological Conditions: Common conditions associated with hypercholesterolemia such as liver cirrhosis, diabetes, dyslipidemias, hepatitis, kidney failure, hepatic steatosis, and non-alcoholic fatty liver disease. Less common causes include primary biliary cirrhosis, hepatitis B, C, and D, hypothyroidism, Hashimoto's disease, and Turner syndrome.
  • Genetics: An unfavorable genetic component can increase the endogenous synthesis of cholesterol, leading to high cholesterol levels even at a young age.

Hereditary Hypercholesterolemia

When high cholesterol levels persist despite a balanced diet and regular physical activity, it may be a condition known as familial hypercholesterolemia or primary hypercholesterolemia. This condition, often rooted in genetics, prompts the body to produce excessive amounts of cholesterol from a young age.

There are three primary forms of hereditary hypercholesterolemia:

  1. Polygenic Hypercholesterolemia: This is the most common form, accounting for over two-thirds of all cases. In this condition, nutritional and environmental factors exacerbate an underlying multi-genetic dysmetabolism. It is particularly prevalent in Western populations, affecting up to 20% of individuals.
  2. Familial Hyperlipidemia and Combined Hyperlipidemia: These are less common but still significant forms of hypercholesterolemia.
  3. Primary Hypercholesterolemia: This is a rare monogenic form, also known as essential or primitive familial hypercholesterolemia. This condition is characterized by insufficient activity of the LDL receptor, due to a mutation in the gene coding for this protein. As a result, LDL blood levels rise proportionally to the decrease in receptor activity, leading to an increase in cholesterol levels. This form of hypercholesterolemia is associated with early-onset coronary heart disease.

Symptoms and Complications of Hypercholesterolemia

Hypercholesterolemia is largely asymptomatic, meaning it usually does not present with noticeable symptoms. However, severe forms of the condition can lead to the development of xanthomas and xanthelasmas, which are cholesterol deposits in the skin and tendons.

Xanthomas are yellow-orange plaques or nodules with a waxy appearance that occur due to lipid accumulation under the skin. These are often seen in individuals with high cholesterol and triglyceride levels. Xanthelasmas, on the other hand, are yellowish-white papular or nodular lesions that occur on the upper and lower eyelids.

High cholesterol is a major risk factor for cardiovascular diseases, which are the leading cause of death in industrialized countries. This is primarily due to the role of cholesterol in the development of atherosclerosis, a degenerative disease that affects large and medium-sized arteries, reducing their elasticity and blood flow.

In atherosclerosis, inflammatory and scarring lesions form on the inner walls of the arteries. These lesions accumulate deposits of lipids and immune cells, making the artery more prone to rupture and obstructing normal blood circulation. This reduces the amount of oxygen and nutrients available to the tissues downstream of the obstruction. The higher the cholesterol levels, the greater the risk of atherosclerosis.

Complications of atherosclerosis include angina pectoris, ischemic heart disease, myocardial infarction, intermittent claudication, erectile dysfunction, and stroke. Symptoms of these conditions can include chest pain, cramps during walking, mental confusion, and headaches.

Diagnosing Hypercholesterolemia

Cholesterol levels can be easily measured with a simple blood test and should be monitored regularly.

In addition to blood tests, doctors may recommend other checks to evaluate the state of heart health and the cardiovascular system. These could include blood pressure measurement, blood sugar control, kidney function evaluation, electrocardiogram (ECG), angiography, and Doppler ultrasound.

It's critical to note that total cholesterolemia alone is a poor predictor of cardiovascular risk. A situation where total cholesterol is within the norm but the HDL fraction is particularly low is much more dangerous than another where total cholesterolemia exceeds the limit value of 200 mg/dL but the HDL fraction is higher in percentage.

Measuring Cholesterol Levels

Cholesterol levels in the blood, or cholesterolemia, are commonly measured to evaluate a person's circulatory system health. The total cholesterol value, which should ideally be less than 200 mg/dl of blood, represents the overall quantity of cholesterol contained in various lipoproteins (LDL, VLDL, HDL). Alongside total cholesterol, it's crucial to measure LDL and HDL quantities.

Adults should measure their cholesterol levels every five years or more frequently if they have one or more risk factors for cardiovascular disease. Children and teenagers should be tested between the ages of 9-11 and 17-21.

Treatment for Hypercholesterolemia

Despite the fact that this condition can be genetically inherited, lifestyle modifications play a crucial role in managing the condition. A well-planned diet, combined with regular physical exercise, can help maintain a healthier lipid balance.

Dietary recommendations typically include:

  • Reducing total energy intake for overweight individuals
  • Limiting total dietary fat to less than 30% of total energy
  • Reducing intake of saturated fatty acids to less than 10% of total energy
  • Minimizing foods rich in hydrogenated oils
  • Reducing consumption of high glycemic index carbohydrates
  • Encouraging consumption of oleic acid and linoleic acid
  • Increasing the intake of complex carbohydrates
  • Increasing the consumption of fruits, vegetables, and legumes
  • Moderating salt intake

If dietary and lifestyle changes are insufficient, lipid-lowering medications may be necessary. These include statins and fibrates, which work synergistically with dietary changes to manage cholesterol levels. Other commonly used medications include ezetimibe, niacin, and bile acid sequestrants.

Preventing Hypercholesterolemia

Prevention is the key strategy to maintain healthy cholesterol levels. This primarily involves maintaining a healthy diet, regular physical activity, weight management, and avoiding smoking. By understanding the factors that influence cholesterol levels and taking proactive steps to manage them, it's possible to reduce the risk of hypercholesterolemia and its associated health complications.

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The Wellyme Team

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