SHM Converge Scientific Abstract ePoster Gallery-When a Mechanical Fall Isn't So Mechanical: A Case of Necrotizing Myositis

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A 61-year-old woman developed two months of progressive proximal muscle weakness, difficulty climbing stairs and rising from a car, and a recent fall. She had no rash, synovitis, or nail changes. Labs showed markedly elevated CK (9,825 IU/L) and aldolase, with mild AST/ALT elevation and normal thyroid and renal function. Because the presentation suggested inflammatory myopathy, atorvastatin was stopped and Rheumatology was consulted.<br /><br />Further evaluation included a myositis antibody panel, HMG-CoA reductase (HMGCR) autoantibodies, and thigh MRI. MRI demonstrated active myositis, prompting muscle biopsy. Pathology showed necrotic and regenerating muscle fibers, consistent with immune-mediated necrotizing myopathy (IMNM). Extended serology revealed high-titer HMGCR autoantibodies, confirming anti-HMGCR-positive IMNM.<br /><br />IMNM is a subtype of idiopathic inflammatory myopathy and includes three forms: anti-SRP-positive, anti-HMGCR-positive, and seronegative disease. It typically presents with subacute, progressive proximal weakness and very high CK levels, usually without the skin findings seen in dermatomyositis or other connective tissue disease features. Dysphagia from pharyngeal muscle involvement may occur. Statin exposure is an important association, especially for anti-HMGCR disease.<br /><br />Management centers on immediate discontinuation of the statin and early immunosuppression. In this case, the patient was started on prednisone followed by azathioprine, with a plan to taper steroids over time. Over five months, CK and aldolase improved substantially. The case emphasizes that hospitalists should recognize IMNM early, particularly in statin users, and involve Rheumatology promptly to avoid delayed diagnosis and treatment.

Asset Subtitle

Richard White

Meta Tag

Author List Richard White

Category Clinical Vignettes

Concept Immune-Mediated Necrotizing Myopathy

Concept Proximal Muscle Weakness

Concept Creatine Kinase

Concept Anti-HMGCR Antibody

Concept Muscle Biopsy

Distinguished Non-Finalist

Presenter Organization Emory School of Medicine Division of Hospital Medicine

Presenting Author Richard White

Track Adult

Keywords

immune-mediated necrotizing myopathy

anti-HMGCR

statin-associated myopathy

proximal muscle weakness

elevated CK

myositis

muscle biopsy

prednisone

azathioprine

rheumatology

Immune-Mediated Necrotizing Myopathy

Proximal Muscle Weakness

Creatine Kinase

Anti-HMGCR Antibody

Muscle Biopsy