Hyperlipidemia Flashcards
What is actually measured when assessing a patient’s lipid levels?
- Total cholesterol
- LDL-C
- HDL-C
- TG
How is the LDL cholestrerol usually measured?
What is the formula called?
Friedewald Formula
Give the equation for the Friedewald Formula
LDL-C = TotChol - HDL-C - TG/5
What do patients have to do before getting a cholesterol level/ lipid measurement?
Why do they have to do this?
Fast
- Triglyceride level will be low
- This means an accurate LDL-C can be obtained using the formula
Hyperlipidemia can be elevated levels of either what 3 things?
- Total cholesterol
- LDL
- Triglycerides
What are the possible causes of secondary hyperlipidemia?
- Nephrotic syndrome (LDL)
- Alcoholism (TG)
- Pregnancy (TG>TC)
- Beta blockers (TG)
- HCTZ (TC, LDL, TG)
What drugs can modestly increase lipid levels?
- Beta blockers (TG)
- HCTZ (TC, LDL, TG)
What are the signs of significant hyperlipidemia?
- Xanthomas
- Tendinous Xanthoma
- Corneal arcus
What are Xanthomas due to?
Where are they commonly found?
- Plaques of lipid-laden histiocytes
- Appear as skin bumps or on eyelids
Where can Tendinous Xanthomas (lipid deposits in tendons) be found commonly?
Achilles
When may corneal arcus be found?
Fundoscopy
At what elevated levels of triglycrides would pancreatitis actually be seen?
> 1000
What is the mechanism behind pancreatitis due to hypertriglyceremia thought be?
Increased chylomicrons in plasma
- Chylomicrons usually formed after meals and cleared
- May obstruct capillaries -> ischemia
- Vessel damage can expose triglycerides to pancreatic lipases
- Triglycerides breakdown -> free fatty acids
- Acid -> tissue injury -> pancreatitis
What are the signs of type 1 dyslipidemia (Hyperchylomicronemia)?
- > 1000 TG
- Milk plasma appearence
- Increased chylomicrons
- Recurrent pancreatitis
- Hepatomegaly
- Xanthomas
How is type 1 dyslipidemia (Hyperchylomicronemia) inherited?
AR
What type 1 dyslipidemia (Hyperchylomicronemia) due to?
2 possible mechanisms
Severe LPL dysfunction
- LPL deficient
- LPL co-factor deficient (apolipoprotein C-II)
What is the treatment for type 1 dyslipidemia (Hyperchylomicronemia)?
Very low fat diet
- Normal lifespan and no incr risk of stherosclerosis
How is Type II familial dyslipidemia (Familial Hypercholesterolemia) inherited?
Aut Dominant
What is thought to cause Type II familial dyslipidemia (Familial Hypercholesterolemia)?
Few or zero LDL receptors
What are the clinical signs / lab findings in Type II familial dyslipidemia (Familial Hypercholesterolemia)?
- V. High LDL (>300 Heterozygote, >700 homozygote)
- Tendon xanthomas, corneal arceus
- Atherosclerosis, MI often in 20s
What is Type III familial dyslipidemia (familial dysbetalipoproteinemia) due to?
Apo-E2 subtype of Apo-E
- Poorly cleared by liver
- Accumulation of chylomicron remnants and VLDL (collectively known as B-lipoproteins)
- Elevated cholesterol and triglycerides
What will TC levels be in Type III familial dyslipidemia (familial dysbetalipoproteinemia)?
Usually mild TC >300mg/dL
What will be seen in Type III familial dyslipidemia (familial dysbetalipoproteinemia)?
- Xanthmoas
- Premature coronary artery disease
If you have ApoE2 allelle (Type III familial dyslipidemia) what are your chances of Alzheimers?
Decreased risk
What is the risk of Alzheimers with an ApoE4 allelle?
Increased risk
What is Type IV familial dyslipidemia (hypertriglyceridemia) due to?
- VLDL overproduction or impaired catabolism
- Increased TG (200-500), not pancreatitis
- Increased VLDL
What is Type IV familial dyslipidemia (hypertriglyceridemia) associated with?
- Type II diabetes
- CVD, premature coronary disease
What familial dyslipidemias are Aut Dominant?
- Type II: Familial Hypercholesterolemia
- Type IV: hypertriglyceridemia
