Lipids in Heart Disease Flashcards
Role of lipids
- make up cell membranes
- absorption of fat soluble vitamins
- maintain membrane fluidity
- thermal insulation
- cellular metabolic regulator
- hormone synthesis
- organ padding
CV RF
Smoking High cholesterol HTN High blood glucose Obesity Age Gender FH Ethnicity
What is cholesterol required for?
Synthesis of :
Vitamin D
Bile Salts
Steroid
Role of chylomicrons
Transport fats from intestinal mucosa to liver
Release TG and some cholesterol and become LDLs
Role of LDLs
Carry fat and cholesterol to bodys cells
Role of HDLs
Carry fat and cholesterol back to liver for excretion
Fasting lipid profile
Serum total cholesterol Serum LDL cholesterol Serum fasting TG Serum HDL cholesterol Cholesterol - HDL ratio
2ry hyperlipidaemia causes
Diet Alcohol Hypothyroidism Nephrotic Syndrome Anorexia Nervosa Obstructive Liver disease Obesity Diabetes Mellitus Pregnancy Acute hepatitis SLE Drugs = thiazides, beta blockers, antiretroviral drugs, antidepressants
Familial Hypercholesterolemia
- hereditary cause
- codominant
- heterozygous
- LDL receptor mutation
- atherosclerosis high risk
- tendon xanthoma
- tuberous xanthoma
- eye xanthelasma
Familial Combined Hyperlipidaemia
- autosomal dominant
- increased secretion of VLDL
Dysbetalipoproteinemia
- apoE2 = binding defective form of apoE
- atherosclerosis risk
- peripheral vascular disease risk
- tuberous xanthoma
- striae palmaris
What is the source of cholesterol in blood?
- diet
- synthesises by liver for steroid hormones
What happens when you take in cholesterol from diet?
- converted to chylomicrons
- LPL (lipoproteinipase) converts it to chylomicron remnant
- goes to liver
What happens if there is a deficiency of LPL?
Increase in chylomicron and less remnant goes to the liver
- increases in VLDL
- high cholesterol in circulation
Cause of FH?
Gene mutation in pathway which clears LDL from bloodstream
What can FH lead to?
Early atherosclerosis and CHD
Inheritance of FH?
Autosomal dominant
Significance of early treatment with FH
High risk of premature CHD
Early treatment = near normal LE
When should you consider FH?
In all adults with total cholesterol greater than 7.5mmol/l
Exclude secondary causes before
How to diagnose FH
Use Simon Broome Criteria
What should patients with definite or possible FH be offered?
Referred to specialist lipid clinic for
- confirmation of diagnosis
- initiation of cascade testing
- treatment
What are the requirements for definite FH in adults diagnosis according to the Simon Broome Criteria?
- total cholesterol >7.5
- LDL-C >4.9
- tendon xanthomata or evidence of these in 1st or 2nd degree relative
OR - identified genetic mutation for FH
What are the requirements for possible FH diagnosis in adults according to the Simon Broome Criteria?
- total cholesterol >7.5
- LDL-C > 4.9
AND at least 1 of - family history of premature CHD
- family history raised total cholesterol in 1st or 2nd degree relative
Causes of tissue lipid accumulation?
- atheromatous plaques
-
What is eruptive xanthomata?
- small itchy nodules
- VLDL/chylomicron associated
- reversible
What is tuberous xanthomata?
- yellow plaques over elbows and knees
- IDL induced
What is xanthelasma?
- periorbital skin deposits
- LDL associated
What are some examples of tissue lipid accumulation?
- xanthelasma
- tuberous xathomata (subcutaneous tissue)
- eruptive xanthomata (subcutaneous tissue)
- corneal arcus (cornea)
- extensor tendons/Achilles tendons
How does hypothyroidism affect LPL?
Reduces activity
Causes of high serum CK
Ethnicity
Hypothyroidism
