Hypercholesterolemia: Diagnosis and Characteristics

LDL = total cholesterol - HDL - (0.2 x fasting triglycerides)

LDL > 3.4 mmol/L

To check for hypothyroidism affecting lipid levels

1.55 mM

Family history of CHD in a first-degree relative (male < 55 years or female < 65 years)

General health assessment and check for kidney disorders

Hypercholesterolemia is characterized by elevated cholesterol levels in the blood, and it increases the risk of cardiovascular diseases by affecting the body's metabolism and associated with heightened risk of cardiovascular diseases.

The two main categories of causes of hypercholesterolemia are congenital causes and acquired causes. Congenital causes are inherited and include genetic disorders such as familial hypercholesterolemia, while acquired causes are lifestyle-related and include factors such as obesity and diabetes.

LDL receptors play a crucial role in removing excess cholesterol from the bloodstream, and mutations in these receptors lead to a deficiency in the removal of LDL cholesterol, resulting in elevated levels of LDL and increased risk of atherosclerosis.

Type 1 familial hypercholesterolemia is characterized by high triglyceride levels, eruptive xanthomas, and pancreatitis, while type 2a is characterized by elevated LDL levels, premature atherosclerosis, and arcus lipoides. The main difference between the two is the type of lipoprotein defect, with type 1 involving chylomicrons and type 2a involving LDL.

The Frederickson classification is a system used to categorize dyslipidemias based on the type of lipoprotein defect. It includes five types, ranging from type 1 to type 5, each with distinct clinical manifestations and lipoprotein defects.

VLDL (very-low-density lipoprotein) is a type of lipoprotein that carries triglycerides from the liver to peripheral tissues, while LDL (low-density lipoprotein) carries cholesterol from the liver to peripheral tissues. Elevated levels of both VLDL and LDL contribute to hypercholesterolemia and increased risk of cardiovascular diseases.

Hypercholesterolemia is a major risk factor for atherosclerosis, as elevated cholesterol levels lead to the deposition of cholesterol in the arteries, resulting in the formation of atherosclerotic plaques and increasing the risk of cardiovascular diseases.

Familial dysbetalipoproteinemia is characterized by premature atherosclerosis, palmar and tuberoeruptive xanthomas, and increased levels of cholesterol and triglycerides. It differs from other types of dyslipidemias in its unique combination of clinical manifestations and lipoprotein defects.

ApoE (apolipoprotein E) is a protein that plays a crucial role in lipid metabolism, and defects in ApoE are a primary cause of familial dysbetalipoproteinemia. The defective ApoE leads to impaired clearance of lipoproteins, resulting in elevated levels of cholesterol and triglycerides and increased risk of cardiovascular diseases.

Acquired causes of hypercholesterolemia include lifestyle-related factors such as obesity, diabetes, physical inactivity, and certain medications. These factors contribute to the development of hypercholesterolemia by affecting lipid metabolism and increasing the risk of cardiovascular diseases.

In younger individuals, Arcus Lipoides Corneae may indicate high cholesterol levels, whereas in older individuals, it is a more common condition.

Severe hypertriglyceridemia can lead to acute pancreatitis due to the toxic effects of high triglyceride levels on pancreatic tissue.

Atherosclerosis progression increases the risk of myocardial infarction, which can manifest as a heart attack or heart muscle damage.

Carotid artery stenosis increases the risk of stroke by reducing brain blood flow, leading to interrupted blood supply and potential brain damage.

The accumulation of LDL in the arterial wall, leading to the formation of fatty deposits and subsequent arterial narrowing and hardening.

Lifestyle changes, such as diet and exercise, can help lower lipid levels and complement medication therapy in managing dyslipidemia.

Initial screening is crucial for identifying lipid disorders and assessing cardiovascular risk, allowing for early intervention and management.

Yellow papules with an erythematous border, typically found on the buttocks, back, and extensor surfaces of extremities.

Palmar xanthomas are associated with type III hyperlipoproteinemia and increased VLDL, while tendinous xanthomas are associated with severe hypercholesterolemia and elevated LDL levels.

The accumulation of lipid deposits in the retinal vessels, leading to their opaque and white appearance during a fundoscopic exam.

Xanthelasmas are bilateral, yellow, flat plaques that appear on the upper eyelids, and are associated with hypercholesterolemia, hyperapobetalipoproteinemia, and elevated LDL levels.

Arterial narrowing and hardening, leading to increased risk of coronary heart disease, myocardial infarction, stroke, and peripheral arterial disease.