Myositis: An Imaging and Clinical Review

[Pages:1]Myositis: An Imaging and Clinical Review

Krishna Kumar, Karen Alexander, A. Keith Rastogi

University of Missouri-Kansas City School of Medicine; Saint Luke's Hospital of Kansas City

INTRODUCTION

? Muscle pain (myalgia) and muscle weakness are common clinical presentations for a variety of pathologies.

? A thorough clinical workup is required, and imaging, particularly magnetic resonance imaging (MRI), can be quite helpful in narrowing the differential diagnosis.

? This exhibit will review the clinical and imaging workup of patients presenting with symptoms of both acute and chronic myositis.

CLINICAL WORKUP

? Thorough history and physical exam. ? Lab assessment: creatine kinase (CK),

erythrocyte sedimentation rate (ESR), Creactive protein (CRP), autoantibodies, electromyography. ? MRI findings alone are nonspecific. The goals of MRI are: to identify if myositis is present, categorize findings as acute or chronic, evaluate extent and severity of involvement, and help guide optimal biopsy location.

MYOSITIS

? Etiologies: dermatomyositis, polymyositis, inclusion body myositis, lupus, rheumatoid arthritis, scleroderma, Sjogrens, scleroderma, infectious myositis, diabetic myositis/myonecrosis.

? Autoantibodies: anti-Jo1, PL-7, PL-12, SRP, Mi-2, anti-CCP, anti-ss (a and b), anti-Ro and anti-La.

ACUTE MYOSITIS ? MRI findings: intramuscular and

myofascial edema with hyperintense signal on T2-weighted (T2W) and short tau inversion recovery (STIR) sequences.

CHRONIC MYOSITIS ? MRI findings: fatty infiltration (T-1

weighted feathery hyperintense signal within muscle), muscle atrophy and no edema on T2W or STIR sequences

CONCLUSION

? MRI is essential in the evaluation of muscle pathology, helping to determine the presence and acuity of myositis. It assists in determining the next clinical step.

? Close collaboration between both clinicians and radiologists is required for final diagnosis and treatment.

References

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