A very interesting case of an elderly female admitted for confusion, proximal weakness and fatigue with AST 1770/ALT 413 with associated CK that peaked at ~80k concerning rhabdomyolysis. Weakness is thought to be due to myopathy (autoimmune vs non-inflammatory).Her CK elevation is thought to be due to statin. She has shown significant improvement from stopping her statin and fluid resuscitation. However, it is important to note that statin induced  necrotizing autoimmune myositis should be on your differential. Some patients may require muscle biopsy to diagnose this which warrants treatment with anti-inflammatory (steroids). The highest risk statins for this presentation include atorvastatin, simvastatin and lovastatin as they are metabolized by cytochrome 450. 

Myopathy ddx

1. Autoimmune
   • Primary
     • Dermatomyositis
     • Polymyositis
     • Inclusion body myositis
   • Secondary
     • Vasculitis
       
2. Non-inflammatory
   • Meds: statin, steroids
   • Toxins: EtOH
   • Critical illness