Dyslipidaemias

Question 1

How is LDL calculated

Answer 1

Total cholesterol - (hdl + TG/2.2)

Only if triglycerides < 4,5

Question 2

Which lab tests should be ordered to diagnose cause of fasting chylomicronaemia

Answer 2

Assay for lipoprotein lipase and apo Cll (activate LPL)

Question 3

Clinical consequence of severe hypertriglyceridaemia?

Answer 3

Tg > 10 - pancreatitis

Question 4

Name 8 common causes secondary dyslipidaemias

Answer 4

• Excessive alcohol
• diabetes
• hypothyroid
• nephrotic syndrome
• chronic renal failure
• cholestasis
• obesity
• drugs; oestrogens, corticosteroids, progestogens, antipsychotics, immunosuppressants

Question 5

Define familial dysbetalipoproteinemia

Answer 5

• Excess IDL and chylomicron remnants
• clinically: fat deposits in palmar creases, tuberous xanthomata

Question 6

Describe, in short, lipoprotein metabolism (5)

Answer 6

• Chylomicrons transport fat from intestine to liver
. In liver, chylomicrons release triglycerides and some cholesterol to become LDL
• LDL carry fat and cholesterol to body cells
• HDL acquire cholesterol from peripheral cells and other lipoproteins, this is esterified by LCAT
• cholesterol esters transferred back to remnant particles which are taken up by liver and excreted

Question 7

Pathology in familial hypercholesteroloemia ?

Answer 7

• Different mutations LDL
• defective apolipoprotein B100, decreasing avidity of LDL for its receptor
• therefore defect in uptake and catabolism LDL

Question 8

How diagnose cause of fasting chylomicronaemia

Answer 8

Assay for LPL and apolipoprotein CII (activate lpl)