We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Editorial |

The Clinical Spectrum of Necrotizing Autoimmune Myopathy A Mixed Bag With Blurred Lines

Matthew N. Meriggioli, MD1
[+] Author Affiliations
1Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois
JAMA Neurol. 2015;72(9):977-979. doi:10.1001/jamaneurol.2015.1517.
Text Size: A A A
Published online


Necrotizing autoimmune myopathy (NAM) is a recently defined subcategory of the acquired idiopathic myopathies, characterized clinically by the subacute onset of proximal weakness, elevated creatine kinase levels, and electromyography revealing an irritable myopathy.1 It is distinguished from other acquired inflammatory myopathies (eg, polymyositis and dermatomyositis) by the histopathological findings of marked muscle fiber necrosis and regeneration with little or no accompanying inflammation. Immunostaining of muscle biopsies reveals macrophages around necrotic muscle fibers without the presence of lymphocytes.2,3 Necrotizing autoimmune myopathy has existed as a distinct nosological entity classified under the acquired idiopathic myopathies since 2004.4 Prior to this, it is likely that many cases were diagnosed as severe cases of polymyositis without inflammation, based on the results of a biopsy, but nevertheless were treated with immunosuppressive drugs. It is important to point out that the histological features of NAM may be seen in either acquired or genetically determined myopathies and that the subacute onset of symptoms and the response to immunotherapy are among the clinical features that help to distinguish it from an inherited or toxic myopathy.

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

First Page Preview

View Large
First page PDF preview





Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.

See Also...
Articles Related By Topic
Related Collections
PubMed Articles

Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice, 3rd ed
The Biological Agent

Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice, 3rd ed
Is There Potentially Compelling Evidence for a Class Effect?