CLS Secondary Causes of Dyslipidemia 3 — Questions and Answers
Question 1: In patients with type 2 diabetes mellitus, which lipid abnormality is MOST characteristic?
- Markedly elevated LDL-C
- Elevated triglycerides, low HDL-C, and small dense LDL particles (Correct answer)
- Isolated HDL reduction with normal TG
- Elevated Lp(a) with normal TG
Correct answer: Elevated triglycerides, low HDL-C, and small dense LDL particles
T2DM classically produces the 'diabetic dyslipidemia' triad: elevated triglycerides, low HDL-C, and a predominance of small dense LDL particles.
Question 2: Acromegaly most commonly causes which type of dyslipidemia?
- Isolated hypercholesterolemia
- Hypertriglyceridemia with or without reduced HDL-C (Correct answer)
- Isolated elevated Lp(a)
- Mixed hyperlipidemia with xanthomas
Correct answer: Hypertriglyceridemia with or without reduced HDL-C
Excess growth hormone in acromegaly promotes lipolysis and hepatic VLDL production, resulting primarily in hypertriglyceridemia.
Question 3: A 35-year-old woman taking oral contraceptives (ethinyl estradiol/progestin) has TG of 680 mg/dL. Which mechanism explains the OCP effect?
- Estrogen inhibits LPL activity and stimulates hepatic VLDL production (Correct answer)
- Progesterone increases intestinal cholesterol absorption
- Estrogen upregulates PCSK9 expression
- Progestin directly inhibits fatty acid oxidation
Correct answer: Estrogen inhibits LPL activity and stimulates hepatic VLDL production
Estrogen in oral contraceptives stimulates hepatic VLDL synthesis and may inhibit lipoprotein lipase, particularly raising triglycerides in genetically susceptible individuals.
Question 4: Which autoimmune condition is associated with secondary dyslipidemia due to production of autoantibodies against lipoprotein lipase?
- Rheumatoid arthritis
- Systemic lupus erythematosus (Correct answer)
- Sjögren's syndrome
- Ankylosing spondylitis
Correct answer: Systemic lupus erythematosus
SLE can produce anti-LPL antibodies, impairing triglyceride-rich lipoprotein clearance and causing severe hypertriglyceridemia.
Question 5: Which atypical antipsychotic is most strongly associated with secondary hypertriglyceridemia and metabolic syndrome?
- Aripiprazole
- Ziprasidone
- Clozapine (Correct answer)
- Lurasidone
Correct answer: Clozapine
Clozapine (and olanzapine) have the highest metabolic liability among atypical antipsychotics, causing weight gain, hypertriglyceridemia, and new-onset diabetes.
Question 6: A patient with untreated hypothyroidism has LDL-C of 195 mg/dL. After levothyroxine therapy achieves euthyroid state, LDL-C falls to 140 mg/dL. What was the primary mechanism of the initial elevated LDL?
- Reduced bile acid synthesis and decreased cholesterol excretion (Correct answer)
- Upregulation of LDL receptors causing paradoxical elevation
- Increased intestinal cholesterol absorption
- Decreased VLDL production with LDL accumulation
Correct answer: Reduced bile acid synthesis and decreased cholesterol excretion
Hypothyroidism reduces LDL receptor expression and bile acid synthesis, impairing LDL clearance and cholesterol catabolism, resulting in elevated LDL-C.
Question 7: Isotretinoin (13-cis retinoic acid) used for acne causes which lipid change most frequently?
- Marked LDL elevation
- Isolated HDL reduction
- Hypertriglyceridemia, sometimes severe (Correct answer)
- Elevated Lp(a)
Correct answer: Hypertriglyceridemia, sometimes severe
Isotretinoin commonly elevates triglycerides (in 25% of patients) and can rarely precipitate pancreatitis-level hypertriglyceridemia.
CLS Secondary Causes of Dyslipidemia 3
In patients with type 2 diabetes mellitus, which lipid abnormality is MOST characteristic?