Lipids Flashcards
3 types of lipids
- cholesterol
- triglycerides
- lipoproteins
what is cholesterol
define/describe
essential element of all animal cell membranes and the backbone of steroid hormones and bile acids
what are triglycerides
txfr energy from food into cells
what are lipoproteins
- transport lipids
- classified by density
- apoprotiein is dense
- triglyceride is less dense
7 types of lipoproteins
- chylomicrons
- low-density lipoprotein
- high-density lipoprotein
- very-low-density lipoprotein
- Apolipoprotein B (apoB)
- Lipoprotein
- non-HDL cholesterol
describe chylomicrons
least dense
found in blood after fatty meals
describe LDL
carry most of our cholesterol
describe VLDL
least dense, large
consists mostly of triglycerides that are txfr to cells
describe HDL
most dense & smallest
participate in reverse cholesterol transport
describe apoB
- protein that carries LDL and helps it bind to the cell wall
- contributes to atherogenesis
describe lipoprotein a (lp(a))
- genetically determined subfraction of LDL
- causal factor in atherosclerosis
- one-time measurement rec in pts w/ family hx of ASCVD
- risk enhancing factor favoring early statin tx
describe non-HDL cholesterol
- surrogate marker of apoB
- measured directly, less sensitive to fasting status
- better predictor of CV risk than LDL
- non-HDL Cholesterol = TC - HDL
which lipid value is most sensitive to fasting?
triglycerides
which lipoprotein carries the most cholesterol
LDL
which lipoprotein is an independent risk for ASCVD
Lp(a)
which lipoprotein represents all apoB containing particles?
non-HDL calculation
what are the components of a lipid panel?
4
- total cholesterol
- LDL
- HDL
- triglycerides
which components of a lipid panel are measured directly? which are calculated?
- direct: TC, HDL, triglycerides
- calc: LDL
equation for TC
HDL + VLDL + LDL
equation for non-HDL cholesterol
TC - HDL
equation for VLDL
& when to use
TG / 5
only if TG is < 400
equation for LDL
TC - HDL - (TG / 5)
what are benchmarks for LDL levels?
5
- less than 100: optimal
- 100-129: near optimal/above optimal
- 130-159: borderline high
- 160-189: high
- more than 190: very high
what are benchmarks for TC levels?
3
- less than 200: desirable
- 200-239: borderline high
- greater than 240: high
what are benchmarks for HDL cholesterol?
2
- less than 40: low
- greater than 60: high
benchmarks of triglycerides?
4
- less than 150: normal
- 150-199: borderline high
- 200-499: high
- more than 500: very high
what is the goal of lipid treatment? when does this goal change?
- to reduce LDL
- when triglycerides are greater than 500
what is the risk of treating when triglycerides are greater than 500?
pancreatitis
Atherosclerosis
associated with?
- high LDL
- low HDL
Atherosclerosis
pathophys
plaque w/ large amounts of cholesterol build up in arterial walls
Atherosclerosis
mostly asx until?
rupture or vessel occlusion (MI or CVA)
Familial Hypercholesterolemia
associated with which genetic components?
3
- defective LDL receptors
- genetic mutations of apo B
- gain of function mutation of PCSK9
Familial Hypercholesterolemia
which lipid is usually elevated?
- total cholesterol
Familial Hypercholesterolemia
describe clinical manifestation of heterozygous pts
- up to 3x normal levels of LDL
- LV disease begins in 30s or 40s
Familial Hypercholesterolemia
describe clinical manifestation of homozygous pts
- extremely high LDL (up to 8x normal)
- atherosclerosis in childhood
- may require plasmapheresis to remove cholesterol
Familial Chylomicronemia
AKA
3 things
- Lipoprotein Lipase Deficiency (LPLD)
- Fredrickson Type 1 Hyperlipoproteinemia
- Familial Hypertriglyceridemia
Familial Chylomicronemia
caused by?
abnormality of LPL that is responsible for ability of itssues to take up triglycerides (TG) from chylomicrons
Familial Chylomicronemia
characterized by?
hypertriglyceridemia
Familial Chylomicronemia
complications
2
- recurrent pancreatitis
- hepatosplenomegaly
Familial Chylomicronemia
important to abstain from?
EtOH
Dysbetalipoproteinemia
elevated levels of?
reminant lipoproteins
Dysbetalipoproteinemia
associated with?
premature ASCVD
Familial Combined Hyperlipidemia
most commonly affected genes?
3
- LDLR
- APOB
- PCSK9
Conditions that affect lipids
AKA- secondary causes of dyslipidemia- 11
- metabolic syndrome
- type 2 diabetes
- uncontrolled hyperglycemia
- obesity
- hypothyroidism
- liver disease
- renal disease
- corticosteroid use
- progestin use
- anabolic steroid use
- alcohol use/abuse
conditions that increase TC
10
- obesity
- uncontrolled DM
- hypothyroidism/Cushing
- nephrotic syndrome
- CKD
- obstructive liver disease
- corticosteroid use
- OCPs
- Diuretics
- Beta Blockers
conditions that decrease TC
3
- hyperthyroidism
- cirrhosis
- malignancy
factor that increases LDL
1
- alcohol use
conditions that decrease HDL
4
- obesity
- sedentary lifestyle
- metabolic syndromes
- beta blockers
conditions that increase triglycerides
6
- DM
- alcohol use
- nephrotic syndrome
- CKD
- OCP
- diuretics
you are treating a pt for high cholesterol. Current LDL is non-calculable, other values are:
* TG > 450
* HDL: 40
* TSH: 10 (normal < 4)
* HgA1C: 9.8
why is her cholesterol not at goal in spite of compliance with cholesterol medications?
must correct DM and TSH