A severe and fatal course of statin-induced necrotizing autoimmune myopathy: a case report

INTRODUCTION: Statin-induced necrotizing autoimmune myopathy is a rare but serious complication of statin therapy, marked by progressive muscle weakness and elevated creatine phosphokinase levels that persist despite discontinuation of the drug. We present a case in which statin-associated myopathy was initially misattributed to hepatic dysfunction due to elevated liver enzymes. Despite early recognition and immunosuppressive therapy, the patient experienced relentless decline, ultimately leading to death. This case highlights the progression and potential severity of SINAM, emphasizing the need for early consideration/screening and intervention. CASE REPORT: A 59-year-old White male with a history of hypertension, hyperlipidemia, type II diabetes, and benign prostatic hyperplasia was started on statin therapy (atorvastatin 20 mg daily) for primary prevention of coronary artery disease. He developed progressively worsening generalized fatigue and weakness, most prominently affecting the upper extremities. Lab tests revealed elevated liver enzymes (ALT and AST), prompting discontinuation of statins. Despite this, symptoms and enzyme levels did not improve. Extensive evaluation, including viral, autoimmune, and gastrointestinal workups, yielded negative or normal results, except for elevated inflammatory markers and creatine phosphokinase, which suggested muscle involvement. Imaging and liver biopsy were unremarkable. Neurological assessment did not explain the symptoms. Given the elevated CPK and persistent symptoms, statin-related myopathy was suspected. A positive anti-HMG-CoA reductase antibody and muscle biopsy confirmed the diagnosis of statin-induced necrotizing autoimmune myopathy. Treatment with corticosteroids prednisone, immunosuppressants (methotrexate, azathioprine), and eventually IVIG failed to treat the disease. The patient's condition deteriorated over 3 years, with worsening muscle weakness, recurrent aspiration, respiratory failure requiring multiple hospitalizations, intubation, and ultimately tracheostomy and gastrostomy tube placement. Despite the treatment, he experienced a continuous decline in functional status. In alignment with his wishes, he transitioned to hospice care and passed away. CONCLUSIONS: This case highlights the importance of considering statin-induced necrotizing autoimmune myopathy (SINAM) in patients presenting with unexplained muscle weakness and persistently elevated liver enzymes, even after discontinuation of statin therapy. The diagnostic complexity and overlap with hepatic pathology can delay recognition and treatment. Despite immunosuppressive therapy, this case demonstrates that SINAM can follow a severe, progressive, and ultimately fatal course. Early identification and prompt intervention are crucial, and this case highlights the importance of heightened clinical awareness of this rare but serious adverse effect of statins.