SHM Converge Scientific Abstract ePoster Gallery-An Unusual Case of Progressive Weakness

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This case report describes statin-induced immune-mediated necrotizing myopathy (SINAM), a rare but serious complication of statin therapy marked by progressive proximal muscle weakness, markedly elevated muscle enzymes, and anti-HMG-CoA reductase antibodies. The condition can continue to worsen even after stopping the statin, making early recognition important. Diagnosis is supported by elevated CK and aldolase, EMG or MRI findings of myopathy, and confirmed by muscle biopsy showing necrotic fibers with limited inflammation. Cancer screening is also recommended because anti-HMGCR myopathy may be associated with malignancy.<br /><br />The patient was a 69-year-old man with hyperlipidemia and diabetes who developed worsening muscle pain and weakness over four years, mainly affecting the lower extremities. He had difficulty climbing stairs and rising from a chair. Although he had been on atorvastatin for about one year, his symptoms began before statin use, and he also reported a family history of weakness. Exam showed diffuse proximal weakness and muscle tenderness. Labs revealed very high CK (16,611) and aldolase (133.3). Workup for malignancy was negative after initial imaging raised concern for colon cancer. Anti-HMGCR antibody testing was positive, and muscle biopsy showed chronic active necrotizing myopathy consistent with statin-induced myopathy.<br /><br />He was diagnosed with autoimmune necrotizing myopathy, improved with high-dose prednisone, and atorvastatin was discontinued. He was later started on methotrexate. The authors note that his symptoms, biopsy findings, and family history suggest he may also have had an underlying metabolic myopathy, with SINAM acting as a “second hit.”

Asset Subtitle

Bradley Clemens

Meta Tag

Author List Bradley Clemens, Mohamed Mohamed, Neelay Purohit, Paul Weber

Category Clinical Vignettes

Concept Statin-induced necrotizing autoimmune myopathy

Concept Proximal Muscle Weakness

Concept Creatine Kinase

Concept Anti-HMGCR Antibody

Concept Muscle Biopsy

Distinguished Non-Finalist

Presenter Organization Corewell Health

Presenting Author Bradley Clemens

Track Adult

Keywords

statin-induced immune-mediated necrotizing myopathy

SINAM

anti-HMGCR antibodies

proximal muscle weakness

elevated creatine kinase

muscle biopsy

atorvastatin

autoimmune necrotizing myopathy

high-dose prednisone

metabolic myopathy

Statin-induced necrotizing autoimmune myopathy

Proximal Muscle Weakness

Creatine Kinase

Anti-HMGCR Antibody

Muscle Biopsy