Lipidemia

Lipidemia is an abnormal amount of lipids in the blood. The term most commonly refers to hyperlipidemia, a condition in which levels of cholesterol or triglycerides are elevated and can contribute to atherosclerosis and cardiovascular disease. Lipidemia can be primary, due to genetic factors affecting lipoprotein production or clearance, or secondary to other conditions such as diabetes, hypothyroidism, nephrotic syndrome, liver disease, obesity, or use of certain medications. Hypolipidemia, or unusually low lipid levels, is less common and may occur with malnutrition, certain illnesses, or advanced liver disease.

Lipoproteins and pathophysiology

Blood lipids travel bound to lipoproteins, including low-density lipoprotein (LDL), high-density lipoprotein (HDL), very-low-density lipoprotein (VLDL), and chylomicrons. Disorders of lipidemia arise from genetic defects in lipoprotein synthesis, processing, or clearance, or from metabolic disturbances that alter lipid production and removal. Elevated LDL cholesterol is a key driver of atherosclerosis, while high triglycerides are associated with pancreatitis risk at very high levels and with increased atherogenic risk, particularly in the presence of low HDL cholesterol.

Diagnosis

A standard lipid panel measures total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides after an overnight fast. Non-HDL cholesterol and apolipoprotein measurements may provide additional information in some cases. Thresholds for treatment vary by guidelines and overall cardiovascular risk, but higher LDL-C, high triglycerides, or low HDL-C generally indicate increased risk.

Management

Lifestyle modification is foundational: a heart-healthy diet, regular physical activity, weight management, and avoidance of tobacco. Pharmacotherapy is commonly used when risk is elevated or targets are not reached with lifestyle changes. Statins are first-line for elevated LDL-C; other agents include ezetimibe, PCSK9 inhibitors, fibrates for hypertriglyceridemia, and omega-3 fatty acids. Management aims to reduce cardiovascular risk and prevent lipid-related complications.