Summary
Definition
History and exam
Key diagnostic factors
- muscle strength fatigability
- ptosis
- diplopia
- dysphagia
- dysarthria
- facial paresis
- proximal limb weakness
- shortness of breath
Risk factors
- family history of autoimmune disorders
- genetic markers
- cancer-targeted therapy
Diagnostic investigations
1st investigations to order
- serum acetylcholine receptor (AChR) antibody analysis
- muscle-specific tyrosine kinase (MuSK) antibodies
- serial pulmonary function tests
Investigations to consider
- striational receptor antibody assays
- repetitive nerve stimulation
- single-fiber EMG
- CT of chest
Treatment algorithm
myasthenic crisis
mild to moderate disease (class I to III)
severe (class IV or V) or refractory disease
Contributors
Authors
Robert P. Lisak, MD, FRCP (E), FAAN, FANA
Parker Webber Chair in Neurology
Professor of Neurology
Professor of Immunology and Microbiology
Wayne State University School of Medicine
Detroit
MI
Disclosures
RPL currently serves on an Advisory Board for Argenx for myasthenia gravis (MG), and was an Advisory Board member for Argenx (developing a clinical trial for chronic inflammatory demyelinating polyneuropathy [CIDP]). RPL has been reimbursed by Argenx the manufacturer of efartigimod for serving on a clinical advisory board. RPL has worked with Alexion (testing a treatment for MG); Novartis (design of research related to primary progressive multiple sclerosis [MS] vs. secondary progressive MS); Horizon Pharmaceuticals (advising on MG and neuromyelitis optica spectrum disorder); Takeda (advising on autoimmune diseases); GLG Consulting, Putnam Consulting, Slingshot Consulting, Haven Consulting, Clearview Consulting, Alpha Sites Consulting, and Insights Consulting (providing insights on the current and future treatments of several neuroimmunologic diseases including MS, MG, Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and neuromyelitis optica spectrum disorder). RPL has presented several CME talks for companies with multiple sources of support (no direct payments to RPL). RPL has received clinical trial grants (no direct payments) for studies in MG (Alexion, Argenx, Ra Pharmaceuticals) and MS (Novartis, Teva, Genentech/Roche, Chugai). He has received royalties from Blackwell Press as an editor of the textbook International Neurology, and from Oxford University Press as an editor of a book, Neuroimmunology. RPL is an author of several papers cited in this topic.
Acknowledgements
Dr Robert Lisak would like to gratefully acknowledge Dr Andrea Corse and Dr Ami Mankodi, previous contributors to this topic.
Disclosures
AC and AM declare that they have no competing interests.
Peer reviewers
Vern C. Juel, MD
Associate Professor of Medicine (Neurology)
Duke University
Durham
NC
Disclosures
VCJ declares that he has no competing interests.
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