Treatment and outcomes in necrotising autoimmune myopathy: An Australian perspective.
Necrotising Autoimmune Myopathy (NAM) presents as a subacute proximal myopathy with high creatine kinase levels. It is associated with statin exposure, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) antibody, connective tissue diseases, signal recognition particle (SRP) antibody and malignancy. This case series presents our Western Australian NAM patient cohort: comparing the subgroup presentations, biopsy appearance and treatment outcomes. We retrospectively collected data on patients diagnosed with NAM at the Western Australian Neuroscience Research Institute between the years 2000 and 2015. We identified 20 patients with Necrotising Autoimmune Myopathy: 14 with anti-HMGCR antibodies; two with anti-SRP antibodies; three with connective tissue disease; two as yet unspecified. Median creatine kinase level was 6047units/L (range 1000-17000). The statin naïve patients with HMGCR antibodies and patients with SRP antibodies were the most severely affected subgroups, with higher creatine kinase levels, and were more resistant to immunotherapy. Two or more immunotherapy agents were required in 90%; eight patients required IVIG and rituximab. Steroid weaning commonly precipitated relapses. Four patients had complete remission, and the remaining patients still require immunotherapy. Necrotising Autoimmune Myopathy is a potentially treatable myopathy, which can be precipitated by statin therapy and requires early, aggressive immunotherapy, usually requiring multiple steroid sparing agents for successful steroid weaning.
Fiona Stanley Hospital, Murdoch, WA, Australia. Electronic address: catherine.ashton@health.wa.gov.au.
Catherine
C
Ashton
Section of Neuropathology, PathWest, Royal Perth Hospital, Perth, WA, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, WA, Australia.
Reimar
R
Junckerstorff
Department of Immunology, PathWest, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia.
Chris
C
Bundell
Department of Immunology, PathWest, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia.
Peter
P
Hollingsworth
Fiona Stanley Hospital, Murdoch, WA, Australia; West Australian Neuroscience Research Institute, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia; Murdoch University, Murdoch, WA, Australia; Notre Dame University, Fremantle, WA, Australia.
Merrilee
M
Needham
D000328:Adult; D000368:Aged; D001315:Australia; D001323:Autoantibodies / Q000097:blood; D001327:Autoimmune Diseases / Q000097:blood / Q000201:enzymology / Q000473:pathology / Q000628:therapy*; D015415:Biomarkers / Q000097:blood; D003240:Connective Tissue Diseases / Q000097:blood / Q000201:enzymology / Q000473:pathology / Q000628:therapy; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000276:immunology; D007155:Immunologic Factors / Q000627:therapeutic use; D007167:Immunotherapy; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000473:pathology; D009135:Muscular Diseases / Q000097:blood / Q000201:enzymology / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D018271:Signal Recognition Particle / Q000276:immunology; D016896:Treatment Outcome
D001323:Autoantibodies; D015415:Biomarkers; D007155:Immunologic Factors; D018271:Signal Recognition Particle; C553220:HMGCR protein, human; D006903:Hydroxymethylglutaryl CoA Reductases; D003402:Creatine Kinase
HMGCR antibodies; Immune mediated necrotising myopathy; Necrotising autoimmune myopathy; Statin myopathy