Hyperlipidaemia

Definition

Hyperlipidaemia is a condition characterised by abnormally high levels of lipids (fats) in the blood, including cholesterol and triglycerides. It is a significant risk factor for cardiovascular diseases, including coronary artery disease, stroke, and peripheral artery disease.

Aetiology

Hyperlipidaemia can be primary (genetic) or secondary to other conditions:

Primary Hyperlipidaemia: Genetic disorders such as familial hypercholesterolaemia.
Secondary Hyperlipidaemia: Caused by lifestyle factors (e.g., poor diet, physical inactivity), medical conditions (e.g., diabetes, hypothyroidism), and certain medications (e.g., corticosteroids, thiazide diuretics).

Pathophysiology

Hyperlipidaemia occurs when there is an imbalance between the production and clearance of lipids in the body. Elevated levels of low-density lipoprotein (LDL) cholesterol and triglycerides contribute to the formation of atherosclerotic plaques in the arterial walls, leading to narrowing and hardening of the arteries (atherosclerosis). This can result in reduced blood flow and increased risk of cardiovascular events.

Risk Factors

Family history of hyperlipidaemia or cardiovascular disease
Poor diet high in saturated fats, trans fats, and cholesterol
Physical inactivity
Obesity
Smoking
Diabetes
Hypertension
Age (men over 45 years, women over 55 years)
Excessive alcohol consumption

Signs and Symptoms

Hyperlipidaemia itself often has no symptoms and is usually detected through blood tests. However, long-term uncontrolled hyperlipidaemia can lead to:

Coronary artery disease: Chest pain (angina), heart attack
Stroke: Sudden weakness, paralysis, difficulty speaking
Peripheral artery disease: Leg pain, numbness
Xanthomas: Yellowish deposits of cholesterol under the skin
Arcus senilis: A white or grey ring around the cornea of the eye

Investigations

Lipid profile: Measures total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides.
Fasting blood glucose: To check for diabetes.
Liver function tests: To assess liver health, especially if statin therapy is being considered.
Thyroid function tests: To rule out hypothyroidism as a secondary cause of hyperlipidaemia.
Renal function tests: To assess kidney function.
QRISK score: An assessment tool used to estimate a person's risk of developing cardiovascular disease over the next 10 years. It helps to guide treatment decisions for hyperlipidaemia and other risk factors (treatment if ≥10).

Management

Primary Care Management

Lifestyle modifications: Encouraging a healthy diet low in saturated fats and cholesterol, regular physical activity, weight management, smoking cessation, and limiting alcohol intake.
Medications:
- Statins: (e.g., atorvastatin, simvastatin) to lower LDL cholesterol.
- Ezetimibe: To reduce the absorption of cholesterol from the intestine, often used in combination with statins.
Monitoring: Regular follow-up to assess lipid levels and monitor for potential side effects of medications.
Education: Providing information on the importance of medication adherence, healthy eating, and regular exercise.

Specialist Management

Referral to a lipid specialist: For patients with familial hypercholesterolaemia or refractory hyperlipidaemia.
Management of associated conditions: Addressing comorbidities such as diabetes, hypertension, and metabolic syndrome.
Cardiologist referral: For patients with established cardiovascular disease or high cardiovascular risk.

Example Management for Hyperlipidaemia

A patient diagnosed with hyperlipidaemia presenting with elevated LDL cholesterol and triglycerides should be managed with lifestyle modifications such as a diet low in saturated fats, regular physical activity, and weight management. Initial pharmacological treatment may include a statin (e.g., atorvastatin) to lower LDL cholesterol and ezetimibe to reduce cholesterol absorption. Regular monitoring of lipid levels and liver function tests is essential to assess the effectiveness of treatment and detect potential side effects. The patient should be educated on the importance of medication adherence, healthy eating, and regular exercise. Referral to a lipid specialist may be considered for patients with familial hypercholesterolaemia or refractory hyperlipidaemia.

References

NICE. (2024). Lipid Modification: Cardiovascular Risk Assessment and the Modification of Blood Lipids for the Primary and Secondary Prevention of Cardiovascular Disease. Retrieved from NICE
NHS. (2023). High Cholesterol. Retrieved from NHS
British Heart Foundation. (2022). Managing Your Cholesterol. Retrieved from British Heart Foundation
European Society of Cardiology (ESC). (2021). Guidelines for the Management of Dyslipidaemias. Retrieved from ESC