Statin-associated Autoimmune Myopathies: A Pathophysiologic Spectrum.
BACKGROUND
Statins have recently been reported to cause a rare autoimmune inflammatory and/or necrotic myopathy that begins or persists after drug cessation.


METHODS
We report on 26 patients seen at a neuromuscular centre between 2005 and 2011 who demonstrated muscle weakness/myalgias and creatine kinase elevations during or after statin treatment with continuation of signs and symptoms despite statin withdrawal.


RESULTS
All patients were treated with immunosuppressive therapy with good response; all improved biochemically and 86% improved clinically. Sixty-five percent of patients who attempted to taper off immunosuppressive therapy relapsed. We report on a novel finding whereby five of the seven patients who underwent multiple biopsies throughout their disease demonstrated a transformation of their histological diagnosis, with four progressing from having myofibre necrosis with minimal or no inflammation to a diagnosis of polymyositis.


CONCLUSIONS
This study offers preliminary evidence that statin-associated necrotizing myopathy and statin-associated polymyositis may not be separate entities but are part of the same pathophysiological spectrum. Both entities respond well to immunosuppression.
1Stanford University School of Medicine,Stanford,California 94305,USA.
Yufan
Y
Wu
2Department of Pathology and Molecular Medicine,McMaster University,Hamilton General Site,Hamilton,Ontario L8L 2X2,Canada.
Boleslaw
B
Lach
2Department of Pathology and Molecular Medicine,McMaster University,Hamilton General Site,Hamilton,Ontario L8L 2X2,Canada.
John P
JP
Provias
3Department of Pediatrics,McMaster Children's Hospital,Hamilton,Ontario L8N 3Z5,Canada.
Mark A
MA
Tarnopolsky
4Department of Medicine,McMaster Children's Hospital,Hamilton,Ontario L8N 3Z5,Canada.
Steven K
SK
Baker
D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009135:Muscular Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology*; D012189:Retrospective Studies
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors