SHM Converge Scientific Abstract ePoster Gallery-Unmasking Antisynthetase Syndrome: A Rare Autoimmune Myopathy Revealed Through Multisystem Injury

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This case describes a 30-year-old previously healthy woman who presented with progressive proximal muscle pain and weakness, intermittent fever, and a hyperpigmented rash. Initial evaluation suggested possible infectious or metabolic causes, especially given her recent immigration history and prior malaria treatment. However, she had markedly elevated muscle and liver enzymes, including a CK of 31,103, AST 1,025, and ALT 868, raising concern for inflammatory myopathy.<br /><br />Further workup showed diffuse muscle edema and enhancement on MRI, positive myositis-associated antibodies including anti–Jo-1 and anti-PL7, and muscle biopsy findings of perifascicular/perivascular inflammation consistent with antisynthetase syndrome (ASyS). Infectious studies were negative, and empiric antimalarial and doxycycline therapy was stopped. Although a Monospot test was positive, EBV serologies were negative, reinforcing the noninfectious diagnosis.<br /><br />ASyS is a rare autoimmune syndrome characterized by inflammatory myopathy, interstitial lung disease, arthritis, fever, Raynaud phenomenon, and mechanic’s hands. Because its features overlap with infection and other autoimmune diseases, it is frequently misdiagnosed. Early recognition is important because interstitial lung disease is common and is the main driver of long-term morbidity and mortality. The syndrome also carries a risk of malignancy depending on antibody subtype.<br /><br />The patient improved rapidly after starting prednisone, with down-trending CK and transaminases within 48 hours. She was discharged on prednisone 60 mg daily and later started on azathioprine as a steroid-sparing agent. This case highlights the importance of considering ASyS in patients with unexplained multisystem illness and of using antibody testing and muscle biopsy to confirm the diagnosis and guide treatment.

Asset Subtitle

Clayton Goddard

Meta Tag

Author List Ahmad T. Allemyar, Clayton Goddard, Vishal Akula

Category Clinical Vignettes

Concept Antisynthetase Syndrome

Concept Inflammatory Myopathy

Concept Interstitial Lung Disease

Concept Myositis-Specific Antibody

Concept Glucocorticoid Therapy

Distinguished Non-Finalist

Presenter Organization Liberty University College of Osteopathic Medicine

Presenting Author Clayton Goddard

Track Adult

Keywords

antisynthetase syndrome

inflammatory myopathy

proximal muscle weakness

elevated creatine kinase

anti-Jo-1 antibody

anti-PL7 antibody

muscle biopsy

interstitial lung disease

prednisone treatment

autoimmune disease

Antisynthetase Syndrome

Inflammatory Myopathy

Interstitial Lung Disease

Myositis-Specific Antibody

Glucocorticoid Therapy