hyperlipidemia

Question 1

how do lipids travel in blood

Answer 1

1. chylomicrons
2. VLDL (mainly TG)
3. LDL (mainly xol)
4. HDL (mainly phospholipids)

Question 2

what is xol a major rf for?

Answer 2

CVD

Question 3

relationship between HDL and CVD

Answer 3

HDL correlates inversely with CVD

Question 4

who needs full fasting lipid profile screening

Answer 4

1. those @ risk of hyperlipidemia if:

• fhx +ve for high xol
• corneal arcus <50yo
• xanthomata/xantholasma

2. those @risk of CVD

• known CVD
• fhx of cvd <60yo
• DM/impaired tolerance of glucose
• HTN
• smoker
• high bmi
• low socioeconomic/asian

Question 5

main 2 types of hyperlipidemia

Answer 5

1. common 1ry hyperlipidemia- )70%), high LDL only
2. familial 1ry hyperlipidemia - multiple phenotypes exist

• high risk of CVD,
• refer to specialist

Question 6

target levels [fasting]

Answer 6

[fasting]

TC: <5mmmol/L

LDL: <3mmol/L

TG: <1.7mmol/L

HDL- men [>1.0mmol] ;; women [>1.2mmol/L]

Question 7

Hyperlipidaemia: secondary causes

Answer 7

Causes of predominantly hypertriglyceridaemia

• diabetes mellitus (types 1 and 2)
• obesity
• alcohol
• chronic renal failure
• drugs: thiazides, non-selective beta-blockers, unopposed oestrogen
• liver disease

Causes of predominantly hypercholesterolaemia

• nephrotic syndrome
• cholestasis
• hypothyroidism

Question 8

phenotypes of hyperlipidemia

Answer 8

1. common [polygenic] hypercholesteralemia = commonest form!!

• chol: 6.5-9
• TG: <2.3
• high LDL [>4.0]
• may have xanthelasma/arcus
• nb xanthomata dont develop

2. familial combined hyperlipidemia

• total chol: 6.5-10.0
• >2.3-12
• high LDL. [>4.0] high VLDL
• low HDL [<1.0]
• here, xanthelasma/xanthomata DO NOT occur
• arcus = oft present
• oft: overweight + have htn

other types of hyperlipidemia to know about:

1. familial hyperchylomicronemia [apo protein lipase/apocII deficiency]

• lipidemia retinalis [creamy appearance of retinal vessels]
• hepatosplenomeg
• eruptive xanthomata [yellow/brown papules surrounded by erythematous hole, on but, post thigh, elbow

2. heterozygous familial hypercholesterolemia [LDL R deficits] = autosomal dom

• 70% have tendon xanthomata
• fhx of high cholesterol

3. dysbetalipoproteinemia

• palmar striae
• tuberoeruptive xanthoma
• prem CAD

4. familial hypertryglyceridemia

• chol- 6.5-12
• TG: 3-6
• high VLDL
• often overweight, over 30

5. type V hyperlipoproteinemia

• TG: 10-30
• eruptive xanthomata
• lipidermia retinalis
• hepatosplenomegaly

Question 9

what is mixed hyperlipidemia?

Answer 9

high LDL + high TG

causes:

• T2DM
• metabolic syndrome
• alcohol abuse
• CRF

Question 10

mx of hyperlipidemia

Answer 10

1. identify familial/2ry hyperlipidemia as mx may vary
2. lifestyle advice
   - aim bmi 20-25
   - miterranean diet
   - increase exercise

TOP RX PRIORITY: IF HAVE KNOWN CVD RISK [no need to calculate their risk if already high]

i2nd RX PRIORITY: if have:

• CKD
• T1DM
• >10% CVD risk [irrespective of baseline lipid levels]

1st line:

20mg atorvastatin @ night [primary prevention]

80mg atorvastatin [2ry prevention/1ry prevention if have kidney disease]

alternative:

40mg simvastatin [SE: myalgia, myositis, high LFTs, abdo pain, ng: grapefruit and cytochrome p450i’s increase serum conc’s]

TARGET PLSAMA XOL DECREASE OF > 40% IN THO WITH CVD

2ND LINE:

EXETEMIBE [cholesterol absorption inhibitor]

• used in statin intolerance/in combo with statin to achieve max target reduction

3rd line:

ALIOROCUMAB - mab agonist, acts to decrease hepatocyte LDL receptor expression

• [v effective at deceasing LDL
• v expensice
• given as injection every 2 weeks]

BEZAFIBRATE [useful in mixed hyperlipidemias, class: fibrates]

ANION EXCHANGE RESINS EG. COLESTYRAMINE

NICOTINIC ACID [high hdl, low ldl, se’s: severe flushes]

ASPIRIN 300MG

if have high TG ==> best to use fribrates/nicotinic acid/fish oil

Question 11

when to make referral

Answer 11

1. use s/s
2. lipid profile
3. fhx
4. judge likelihood of familial lipid disorder rather than strict cut off values

exclude other causes:

• excess alcohol
• uncontrolled DM
• hypothyroidism
• liver disease
• nephrotic syndrome

Question 12

when to consider poss familial hypercholesterolemia if have what figures..?

Answer 12

TC >7.5 mmol/L

fhx of prem CAD

Question 13

arrange specialist assessment if:

Answer 13

TC >9.0

non hdl xol 1.7.5 [even if fhx neg]

Question 14

urgent specialist review if:

Answer 14

TG = >20mmol/L

• not due to excess alcohol/poor glycemic control

==> if TG 10-20: repeast test w/i 2 weeks + review for 2ry causes of high cholesterol

Question 15

what does non HDL mean?

Answer 15

non-HDL= TC-HDL

gives a better assessent for risk of heart disease esp if you have high TG

usually base risk depending on LDL levels but sometimes heart attacks occur even when LDL levels are low.

Question 16

s/s of high xol

Answer 16

xanthelasmas- xol deposits on eye [xanathalsma palpebrae]

corneal arcus

xanthomas- xol deposits in skin

lipaemia retinalis= turbid blood in retinal vessels, rare

if hyperlipidemia is 2ry to other conditions esp hypothyroidism/renal fiure= s/s of these conditions will be present

Question 17

ix

Answer 17

1. measure fasting xol + TG levels
   - pt follows normal diet 2 weeks preceding test
   - any drugs affecting lipid metabolism= withdrawn
   - results may be affected by acute illness + shouldnt be done 24hrs-weeks cos lipid levels FALL [following major stress eg. MI]
2. more detailed lipid profile- gices more info

total xol

HDL

TG

TC:HDL xol ratio

3. examination of stored serum
   - raised VLDL- causes milky appearance
   - chylomicronemia- creamy upper layer w/ clear plasa beneath
4. ix for 2ry causes of hyperlipidemia: fbc, esr, tft, lfts