Lipid Biochemistry USMLE Step 1 Practice Question
A 62-year-old woman on atorvastatin 80 mg daily for 6 months presents with progressive myalgias and proximal muscle weakness. Vital signs: BP 138/82, HR 88, RR 16, Temp 37°C, SpO2 98%. Serum creatine kinase is markedly elevated at 2,500 U/L; urinalysis shows no myoglobinuria. LDL cholesterol decreased appropriately to 65 mg/dL. She denies recent alcohol use or concurrent medications. Which mechanism best explains statin-induced myotoxicity?
Answer choices
- AEnhanced muscle protein degradation through upregulation of ubiquitin-proteasome pathway
- BAccumulation of oxidized LDL in the muscle membrane
- CDepletion of mevalonate-derived products essential for protein prenylation and mitochondrial functionCorrect answer
- DIncreased circulating triglycerides causing lipotoxicity in muscle
- EDirect inhibition of myosin heavy chain synthesis
- FCompetitive inhibition of carnitine palmitoyltransferase-1 reducing mitochondrial fatty acid oxidation
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