Lipids

Question 1

After finding high lipid concentrations in the serum, what tests would you employ to confirm or exclude the secondary causes of hyperlipidemia?

Answer 1

1. Check for metabolic syndrome (central obesity, BP, fasting glucose, serum triglyceride and HDL cholesterol).
2. Alcoholism? Alcohol will reduce beta-oxidation.
3. Hypothyroidism (check TS, T3 and T4)
4. Check for kidney disease (GFR, proteinuria, creatinine)
5. Cholestasis (high lipoprotein X)
6. Hepatic disease (ASAT, ALAT, albumin and GGT)
7. Cushing’s disease (measure serum cortisol, dexamethason test)
8. Pregnancy?
9. Glycogen storage disease?

Question 2

The laboratory parameters of a male person having normal blood pressure and a BMI of 23 are:

Serum TG: 1.5 mmol/l
Serum LDL-cholesterol: 4.4 mmol/l
Serum CRP: 5 mg/l

What is the risk of CHD for this person? What are the risk factors of aterosclerosis?

Answer 2

Serum TG: 1.5 mmol/l (normal 0,8-1,7 mmol/l)
Serum LDL-cholesterol: 4.4 mmol/l (high)
Serum CRP: 5 mg/l (slightly elevated, 3 mg/l is the cut-off value)

Because of high CPR (maybe som kind of chronic inflammation) and high LDL, this patients is at high risk for developing atherosclerosis. Atherosclerosis is the basis for CHD.

Lifestyle changes can change this.

Risk factors for atherosclerosis:
Smoking, high LDL, excess alcohol, eating food rich in LDL, stress, age, gender, DM, hypertension, inflammation, genetics.

Question 3

A 45 year-old man has the following parameters:

Waist circumference: 110 cm
BP: 140/90 mmHg
HDL-C: 0.9 mmol/l
Fasting blood glucose: 6.3 mmol/l

What is your opinion about the risk of CHD for this person?

Answer 3

Waist circumference: 110 cm (above 102 cm)
BP: 140/90 mmHg (too high)
HDL-C: 0.9 mmol/l (should be above 1.0 mmol/l in men)
Fasting blood glucose: 6.3 mmol/l (should be below 5.5 mmol/l)

This person has four criteria for metabolic syndrome, which mean he has metabolic syndrome (3 criteria needed).
Lifestyle changes is necessary as these factors put him at increased risk for developing CHD.

Question 4

A 35-year old man wanted to be screened for possible ischemic heart disease because his father died early from a heart attack. The patient was not obese, and was a non-smoker. On examination, his BP was normal. The only abnormality was a xanthoma arising at his Achilles’ tendon. An ECG taken at rest was normal, but ischemic changes developed on exercise.

Fasting lipids:
Serum cholesterol: 8.7 mmol/l
Triglyceride: 1.1 mmol/l

What is the likely diagnosis and how can you confirm it?

Answer 4

Fasting lipids:
Serum cholesterol: 8.7 mmol/l (normal 3.6-5.2 mmol/l)
Triglyceride: 1.1 mmol/l (normal 0.8-1.7 mmol/l)

Serum cholesterol is very high, but triglyceride is within normal. He does not qualify for metabolic syndrome. I suspect familial hypercholesterolemia (mutation in LDL receptor) because of the high cholesterol levels and xanthomas. Genetic testing is necessary to confirm diagnosis. People with familial hypercholesterolemia are at increased risk for developing atherosclerosis and CHD.

Question 5

A middle-aged man saw his family doctor because he got rashes. On examination he was found to have extensive yellowish papules with an erythematosus base on his buttocks and elbows, and he had orange-yellow discolouration on the palmar creases.

Fasting lipids:
Serum cholesterol: 7.6 mmol/l
Triglycerides: 8.1 mmol/l

What is your diagnosis?

Answer 5

Fasting lipids:
Serum cholesterol: 7.6 mmol/l (3.6-5.2 mmol/l - it is very high)
Triglycerides: 8.1 mmol/l (0.8-1.7 mmol/l)

Both serum cholesterol and serum triglyceride was high.
Discoloured palmar creases: xanthoma striatum palmare.
This is type III familial hyperlipoproteinemia. It is due to an autosomal recessive ApoE mutation (defective ApoE2). ApoE2 removes VLDL remnants. Genetic testing to confirm, and it is recessive autosomal, so both alleles need to be mutated.

The papules comes from cholesterol accumulation within scavenging macrophages.