A case of seronegative immune-mediated necrotizing myopathy
CUI Lin
XIE Bingxin
ZHANG Shifa
Abstract：A case of statin-induced immune necrotizing myopathy with negative autoantibodies is reported.A 67-year-old female presented with generalized weakness and limb muscle soreness for 3 months,with worsening symptoms over the past month.She had been taking statins orally for lipid-lowering therapy for 10 years.Skin examination revealed no skin lesions throughout the body.Patient had difficulty to squat and stand up,without muscle atrophy in the limbs.Muscle strength was grade Ⅳ,and there was mild tenderness upon palpation of the upper limbs and thigh muscles.Laboratory tests showed an ESR of 34 mm/h,AMA-M2(WB)strongly positive(+++),CK level of 530 U/L,CK-MB level of 830 U/L,and negative for anti-signal recognition particle antibody,anti-3-hydroxy-3-methylglutaryl-CoA reductase antibody,and dermatomyositis-specific anti-MDA5.LDH was normal.Electromyography showed myogenic damage in the biceps brachii and anterior tibial muscles.Biopsy of the biceps brachii revealed mild muscle degeneration,with no inflammatory cell infiltration.Magnetic resonance imaging of the limbs showed no abnormali-ties.Clinical diagnosis was seronegative immune-mediated necrotizing myopathy.After systematic treatment with glucocorticoids and mycophenolate mofetil,muscle pain and weakness resolved,and the laboratory test indicators improved significantly.After one year of maintenance therapy,there has been no recurrence to date.
Keywords：immune-mediated necrotizing myopathyautoantibodydiagnosistreatment
Publication Date：2025-08-28
Online Publishing Date：2025-09-23(First online date of this platform, not the publication date of the document)
Pages：5( 589-593 )