Lipids and Purines Lab Questions

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

• Obesity/Metabolic Syndrome: [FFA]↑,BMI, Fasting Glucose
• DM: [FFA+Ketone]↑, Random Glucose then Fasting Glucose then OGTT. DM Type II = VLDL↑.
• Hypothyroidism: TSH, T3, T4
• Kidney Disease/Transplant: Proteinuria from High Protein synthesis (Apo) / Immunosupression GC - FFA↑
• Chloestasis: LPX↑(Abnormal low LDL)
• Hepatic Disease: ALAT/ASAT/Albumin/GGT
• Alcoholism: CETP Inhibited-HDL↑
• Pregnancy: HL↓ and VLDL↑

Question 2

The laboratory parameters of a male person having normal blood pressure, BMI 23 kg/m2 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 atherosclerosis?

Answer 2

High risk of CHD:

• CRP↑ although still in normal range
• LDL↑ >3.4mM

Atherosclerosis Risk Factors:

• Modifiable: Smoking, Excercise, HTN, Diet, Stress
• Non-Modifiable: Age,Sex, Genetic, Diseases

Question 3

A 45 year old man has the following parameters:
Waist Circumference: 110 cm
BP: 140/90 mmHg
HDL: 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

4 signs confirm Metabolic Syndrome! :

1. BP↑ - Bengin Hypertension
2. HDL↓
3. Waist Circ.↑
4. Glucose↑- IFG (Insulin Resistance) (OGTT is for further checking in 6-7 mM/l range)
5. or also high TAG could confirm metabolic sy.

• High risk for Cornary Heart Disease!

Question 4

A 35year 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 nonsmoker. On examination his blood pressure was normal and the only abnormality was tendon xanthomata arising from the Achilles tendons. 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 most likely diagnosis and how can you confirm it?

Answer 4

• High Serum Cholesterol (>5.2 mM) with Normal TG: Type IIa Phenotype Hyperlipidemia - Suggestive of Familial Hypercholesterolemia (also Xanthomas)
• Genetic Testing for LDLR or ApoB mutation (Autosomal Dominant)
• Heterozygous form - CHD as Young adults
• Homozygous form - Childhood CHD↑ + Xanthomas
• Treatment: Statins, Diet, Excercise

Question 5

A middleaged man saw his family doctor, because he got rashes. On examination he was found to have extensive yellowish papules, with an erythematous base, on his buttocks and elbows and orange yellow discoloration
of the palmar creases. Fasting lipids:

serum cholesterol 7.6 mmol/l

triglyceride 8.1 mmol/l.
What is your diagnosis?

Answer 5

Probably Familial Type III Hyperlipoproteinemia:

• Serum Cholesterol↑ (>5.2mM)
• Serum TAG↑↑↑ (>1.7mM)
• Xanthoma Striatum Palmare sign

​-Genetic Testing: Autosomal Recessive ApoE Mutation in two alleles

ApoE usually would remove the IDLs so this is also called remnant hyperlipidemia.

Question 6

Purine Metabolism:

• Source of Purines
• Product of Metabolism
• Abnormalities

Answer 6

• Source: Meat
• Uric Acid and Water are the Products of Xanthine Oxydase in the breakdown of Purines
• Abnormalities in nucleotide enzymatic pathway from Drugs/Tumors/High-Fructose Corn syrup can cause: Gout (Elderly), Lesch-Nyhan syndrome or Kidney Urate-Amonium stones.