Clinical aspects of lipids

Question 1

What are the 2 key lipids we should know?

Answer 1

Triacylglyceride
Cholesterol

Question 2

What is Tendon Xanthoma?

Answer 2

Lipid deposits found along the Achilles tendon

Question 3

What is Xanthelasma?

Answer 3

Lipid deposits around the eyes

Question 4

What is Corneal arcus?

Answer 4

A white/grey ring around the iris/cornea

Question 5

What is arcus senilis?

Answer 5

The term given to corneal arcus in the elderly

Question 6

What are some common symptoms of familial hypercholesterolaemia?

Answer 6

Tendon Xanthoma
Xanthelasma
Corneal arcus
Milky serum of blood

Question 7

What is measured for in a cholesterol test?

Answer 7

Total cholesterol
HDL - cholesterol
Triglycerides
Total:HDL-C ratio
LDL cholesterol

Question 8

How do statins mainly work?

Answer 8

Statins are HMG CoA reductase inhibitors
This increases expression of LDL receptors on its surface, meaning that it can take up and break down more LDL-C

Question 9

What are the functions of cholesterol?

Answer 9

Lower cholesterol
Reduce smooth muscle migration
Reduce foam cell formation
Reduce T-cell activation
Reduce adhesion and platelet aggregation
Reduce adherence and entry of leukocytes

Question 10

What are some examples of statins?

Answer 10

Simvastatin
Atorvastatin
Rosuvastatin
Fluvastatin
Pravastatin

Question 11

What are some examples of PCSK-9 inhibitors (Proprotein Convertase Subtilisin/Kexin type 9)?

Answer 11

Alirocumab
Evolocumab

Question 12

What is an example of a fibrate?

Answer 12

Bezofibrate

Question 13

What is an advantage of a fibrate?

Answer 13

They decrease triglycerides by a much larger amount than other drugs

Question 14

What are the uses of ezetimibe?

Answer 14

It is prescribed in those who can’t take statins, although they aren’t very useful

Question 15

What are the advantages of simvastatin?

Answer 15

It has a reasonably high efficacy and is backed by a large amount of evidence

Question 16

What are the advantages of atorvastatin?

Answer 16

It has a higher efficacy than simvastatin and is backed by a large amount of evidence

Question 17

What are the advantages of fluvastatin?

Answer 17

It has a very high patient safety level and is used in those who can’t tolerate statins

Question 18

What are the advantages of rosuvastatin?

Answer 18

It has the highest efficacy, some evidence and is metabolised in a different way to most other drugs, so has fewer drug interactions

Question 19

What are the advantages of pravastatin?

Answer 19

There is good evidence and is metabolised in a different way to most other drugs, so has fewer drug interactions

Question 20

What dose of rosuvastatin is equal to 80mg of simvastatin?

Answer 20

10mg

Question 21

What enzyme metabolises atorvastatin, simvastatin and lovastatin?

Answer 21

Cytochrome P450 3A4

Question 22

How can ketoconazole, erythromycin, diltiazem and the furanocoumarins found in grapefruits affect statins?

Answer 22

These are all metabolised by Cytochrome P450 3A4 and cause permanent inactivation of the enzyme. This slows metabolism of statins and so increases blood plasma levels of them

Question 23

What is the risk of increased blood plasma levels of statins?

Answer 23

This increases the risk of rhabdomyolysis

Question 24

How can phenytoin, barbiturates, carbamazepine and rifampicin affect statins?

Answer 24

They are all powerful inducers of the Cytochrome P450 3A4 and so increase metabolism of statins, thus decreasing blood plasma levels of them

Question 25

Is the familial hypercholesterolaemia mutation autosomal recessive or dominant?

Answer 25

Dominant

Question 26

How does hypertriglyceridaemia cause acute pancreatitis?

Answer 26

Chylomicrons are very large and can obstruct capillaries in the pancreas, leading to localised ischaemia and acidaemia
This local damage causes the release of pancreatic lipases which reacts with triglycerides
The degeneration of triglycerides to free fatty acids can lead to cytotoxic injury, resulting in further local injury and inflammation