This document summarizes lipid disorders and their treatment. It defines lipids as triglycerides and cholesterol, which are components of cell membranes and carriers of dietary fat and cholesterol in the body. Hyperlipidemias can be primary genetic disorders affecting lipid transport and metabolism or secondary due to other conditions. Elevated cholesterol and triglycerides increase cardiovascular risks. Treatment involves lifestyle changes like diet modification and exercise as well as medications like statins to lower LDL cholesterol and fibrates to lower triglycerides.

1. Lipid disorders
Lipids = triglycerides & cholesterol

2. Basics
 Fatty acids- triglycerides- dietary fat
 Source & store of energy
 Component of phospholipids in cell membrane
 Cholesterol- derived from animal fat in diet
 Synthesised in liver, excreted in bile & recycled from intestine
 Component of cell membrane, bile acids, steroid hormones,
fat-soluble vitamins-A,D,E,K
 Transport- as lipoproteins
 Chylomicrons- apoB48- diet-derived lipids to body cells
 LDL- apoB100- carry cholesterol around the body
 HDL- apoAI/II- carry cholesterol from cells to liver for excretion

3. Hyperlipidemia
 Primary- familial
 I- hyperchylomicronemia- deficiency of lipoprotein lipase- raised
chylomicrons-TG- xanthomas, pacreatitis
 II- hypercholesterolemia- LDL receptor defect- raised LDL ±TG-
xanthelasma, tendon xanthoma, increased risk of CAD
 III- dysbetalipoproteinemia- defect in apoE2 synthesis
 IV- hypertriglyceridemia- impaired VLDL metabolism-
TG increased
 Secondary-
 Diabetes mellitus, syndrome X
 Hypothyroidism, nephrotic syndrome, alcohol intake
 Drugs- diuretics, β-blockers, estrogens

4. Clinical
 Raised cholesterol- increased risk of CVD,
xanthelasma, tendon xanthoma, arcus senilis
 Raised TG- xanthoma, pancreatitis,
lipemic serum
 Measurement- fasting, direct or derived
 Screening- USPSTF
 Men >35, women >45
 Earlier in individuals with other risk factors of CAD

5. Target
LDL <100 mg/dl,
preferably <70

6. Treatment
 Lifestyle changes-
 Total fat intake- ~20-30% calories
 Cholesterol intake- <200 mg/d
 Quit smoking, weight control
 Drugs-
 Cholesterol/LDL- statins, fenofibrate, ezetimibe
 Triglycerides- diet, fibrates, ω-3 fish oil
 Low HDL-?- fibrate- after lifestyle changes

7. Treatment
 Lifestyle changes-
 Total fat intake- ~20-30% calories
 Cholesterol intake- <200 mg/d
 Quit smoking, weight control
 Drugs-
 Cholesterol/LDL- statins, fenofibrate, ezetimibe
 Triglycerides- diet, fibrates, ω-3 fish oil
 Low HDL-?- fibrate- after lifestyle changes