Detailed Explanation of Hyperlipidemia: Etiology, Classification, and its Impact on Blood Lipids

Primary hyperlipidemia: Primary hyperlipidemia refers to hyperlipidemia caused by congenital defects in lipid and lipoprotein metabolism (familial) and certain environmental factors through various mechanisms, excluding secondary hyperlipidemia caused by systemic diseases.

Congenital defects in lipid and lipoprotein metabolism are mainly the result of genetic abnormalities. Environmental factors include diet, medications, and unhealthy lifestyle habits.

Secondary hyperlipidemia: Secondary hyperlipidemia refers to abnormal blood lipids caused by other primary diseases or medications. These diseases include diabetes, hypothyroidism, nephrotic syndrome, renal failure, liver disease, pancreatic disease, myeloma, gout, acute porphyria, Cushing's syndrome, etc. In addition, certain medications such as beta-blockers, diuretics, and glucocorticoids can also cause secondary hyperlipidemia. Secondary hyperlipidemia is quite common clinically. Treatment should address both the symptoms and the underlying cause; the primary disease should not be neglected, otherwise the problem cannot be fundamentally solved.

Clinical manifestations of hyperlipidemia: Hyperlipidemia often presents clinically as dizziness, fatigue, insomnia, forgetfulness, limb numbness, chest tightness, and palpitations. Its symptoms can be confused with those of other diseases; some patients have high blood lipids but are asymptomatic, and hyperlipidemia is often discovered during routine blood tests. Furthermore, hyperlipidemia is frequently accompanied by overweight and obesity.

Long-term high blood lipids lead to atherosclerosis caused by lipid deposition in the vascular endothelium, which can cause coronary heart disease and peripheral artery disease, manifesting as angina pectoris, myocardial infarction, stroke, and intermittent claudication (pain after limb activity).

In hyperlipidemia, lipid deposition in the dermis can cause xanthoma, which appears as abnormal, localized skin protrusions. These protrusions can be yellow, orange-yellow, or brownish-red in color, and often present as nodules, plaques, or papules.

A small number of patients with hyperlipidemia may also develop corneal arcus and lipemic fundus changes. Arcus senilis, also known as corneal arcus, is often associated with hyperlipidemia, particularly familial hypercholesterolemia, especially in individuals under 40 years of age, though its specificity is not high. Fundus changes in hyperlipidemia are caused by the deposition of large triglyceride-rich lipoprotein particles on the small arteries of the fundus, leading to light refraction. This is often a characteristic manifestation of severe hypertriglyceridemia accompanied by chylomicronemia.

Significant hypertriglyceridemia can cause acute pancreatitis.