Clinical Reasoning: Rhabdomyolysis after combined treatment with simvastatin and fluconazole

A 65-year-old woman with obesity, hypertension, coronary artery disease, ventricular tachycardia, and hypercholesterolemia presented with 2 weeks of progressive, proximal muscle tenderness and weakness.She was unable to walk.Neurologic examination revealed a severe proximal tetraparesis predominantly of the legs.Sensation was normal.The patellar reflex was slightly reduced on the right side.The remainder of the examination was normal.Her medical history revealed that she had been treated 3 weeks earlier with fluconazole 800 mg daily for 3 weeks, for a Candida albicans infection of her internal defibrillator.Simultaneously she had been taking simvastatin 40 mg daily for 5 years. Questions for consideration:1. What is the differential diagnosis for symmetric proximal weakness?2. What tests would you carry out next?