Statin-Induced Necrotizing Autoimmune Myositis

Area of Science:

• Immunology
• Neurology
• Cardiology

Background:

• Statins are widely prescribed for atherosclerotic cardiovascular disease (ASCVD) prevention.
• An estimated 6-10% of patients experience statin intolerance, often due to muscle aches.
• Guidelines recommend statin use for primary prevention in adults aged 40-75 with elevated cardiovascular risk.

Observation:

• A 71-year-old female presented with proximal muscle aches and weakness after a year of atorvastatin use.
• Elevated creatinine kinase (4,166 U/L) and MRI findings of muscle edema were noted.
• High anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase antibody levels confirmed the diagnosis.

Findings:

• The patient was diagnosed with statin-induced necrotizing autoimmune myositis (SNAM).
• Muscle biopsy showed necrotic muscle fibers.
• Treatment involved intravenous methylprednisolone, mycophenolate mofetil, and tacrolimus.

Implications:

• SNAM is an exceedingly rare but serious complication of statin therapy.
• Early diagnosis and immunosuppressive treatment are crucial for recovery.
• This case highlights the importance of considering autoimmune myositis in patients with unexplained muscle symptoms during statin use.