Laboratory Diagnosis of Lipid Disorders

Question 1

What is hyperlipidemia

Answer 1

> hyperlipidemia is elevated lipid or lipoproteins in the blood.
Primary: unknown
secondary: causes by complications of other disease

Question 2

Afterfindinghighlipidconcentrationsintheserum,whattestswouldyou
employtoconfirmorexcludethesecondarycausesofhyperlipidemia?

Answer 2

1) DM -> WHO guidelines
2) Hyperthyroidism - check TSH, T3, T4
3) Obeisity/Anorexia - check BMI/waist circumfrence
4) Alcholism: ASAT/ALAT/ gammaGT, serum alchol
5) Nephrotic Syndrome (depletion of protein leading to compensatory lipid production in liver: albumin, ALAT, ASAT, creatine, urea, electrolytes)
6) other kidney disease (creatine, acidosis, hyperhosphatemia, PTH levels)
7) Cholestasis
8) Hyperuricemia
9) estrogen therapy -> e2 incrre. TAG AND HDL-C
10) Glycogen storage disease
11) drugs (b-blockers, barbituates)

Question 3

The laboratoryparameters of a male person having normal blood pressure, BMI
23 kg/m2 are:
serum TG: 1.5 mmol/l
serum LDL­cholesterol: 4.4 mmol/l
serum CRP: 5 mg/l
What is the risk of CHD for this person? What are the risk factors of
atherosclerosis?

Answer 3

> Serum TG is normal (0.8-2.3)
serum LDL-CH high (3-4)
serum CRP is normal(1-8) but it not ok should be less than 3. –> risk for atherosclerosis as it an APP

w/ serum LDL at 4.4 and CRP at 5 -high risk for CHD (8x more, with just LDL it 3x more)

RISK FACTORS:
non influential: age,sex, famililar, diseases (DM)
influential: smoking, stress, diet, exersizes, high BP

Question 4

A45­year­oldmanhasthefollowing parameters:
waistcircumference:110cm
BP:140/90mmHg
HDL­C:0.9mmol/l
fastingbloodglucose:6.3mmol/l
WhatisyouropinionabouttheriskofCHDforthisperson?

Answer 4

none of these parameters look good.

> obese: (>102cm)
Low Hdl chol (more than 1mmol/L)
high BP (HT)
Fasting blood glucose too high too.

HIGH RISK for CVD as he has metabolic syndrome (3/5 fufilled)

Question 5

Metabolic syndrome

Answer 5

1) adrogenous obeisity (m: 102, f: 88)
2) High Tag (>1.7)
3) Low HDL (less than 1 for male, less than 1.3 for female)
4) High BP (140/90)
5) Insulin resistance

Question 6

A35­year­oldmanwantedtobescreenedforpossibleischemicheartdisease
becausehisfatherdiedearlyfroma heartattack.Thepatientwasnotobese
andwasa non­smoker.Onexaminationhisbloodpressurewasnormalandthe
onlyabnormalitywastendonxanthomataarisingfromtheAchillestendons.An
ECGtakenatrestwasnormalbutischemicchangesdevelopedonexercise.
Fastinglipids:serumcholesterol8.7mmol/l,triglyceride1.1mmol/l.
Whatisthemostlikelydiagnosisandhowcanyou confirmit?

Answer 6

Familial Hypercholestremia phenotype IIa (elevation in chol and normal serum TG)

• serum chol should be 3.6-5.2
• tag (0.8-1.7)
• heterzygous case most common
• mutation in LDL (macrophages take up -> xanthomas/ CHD (as ldl will not inhibit cholestrol synthesis)

Other symptoms:

• xanthelasm (chol in skin blw eyelid)
• arcus senilis (chol in cornea stroma)

Tests:

1) Genetic testings (expensive)
2) Fibroblast tissue culture (Look at number of ldl receptors on cells)
3) Familial History

Treatment:

1) statins (20-40mg/day)
2) checkup once a year
3) severe cases 160 mg/day (may be toxic to myocytes -> HF)

Question 7

Amiddle­agedmansawhisfamilydoctor,becausehegotrashes.On
examinationhewasfoundtohaveextensiveyellowishpapules,withan
erythematousbase,onhisbuttocksandelbowsandorange­yellowdiscoloration
ofthepalmarcreases.
Fasting lipids:
serumcholesterol7.6mmol/l,
triglyceride 8.1mmol/l.
Whatisyourdiagnosis?

Answer 7

> xanthomas indicate -> primary lipidemia
Serum chol and TG above normal

indicate: Familial dsybetalipoproteinemia

where:
Apo-E2 synthesis is defective so less uptake of IDL and chylomicrons thru LDL-R and LRP in liver (so accumulate in serum)

Tests:

• genetic test for E2
• electrophoresis for protein