Myasthenia gravis

Last reviewed: 18 Apr 2022
Last updated: 01 Apr 2021



History and exam

Key diagnostic factors

  • muscle fatigability
  • ptosis
  • diplopia
  • dysphagia
  • dysarthria
  • facial paresis
  • proximal limb weakness
  • shortness of breath
More key diagnostic factors

Risk factors

  • family history of autoimmune disorders
  • genetic markers
  • cancer-targeted therapy
More risk factors

Diagnostic investigations

1st investigations to order

  • serum acetylcholine receptor (AChR) antibody analysis
  • muscle-specific tyrosine kinase (MuSK) antibodies
  • serial pulmonary function tests
More 1st investigations to order

Investigations to consider

  • striational receptor antibody assays
  • repetitive nerve stimulation
  • single-fiber EMG
  • CT of chest
More investigations to consider

Treatment algorithm


severe disease (class IV and V, myasthenic crisis)


mild disease (class I and II)

moderate disease (class III)

severe disease (post-myasthenic crisis): no intolerance or contraindication to immunosuppressants

severe disease (post-myasthenic crisis): intolerance or contraindication to immunosuppressants



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




RPL is an Advisory Board member for Argenx (developing a clinical trial for chronic inflammatory demyelinating polyneuropathy [CIDP]). RPL has worked with Alexion (testing a treatment for myasthenia gravis); Novartis (design of research related to primary progressive MS vs. secondary progressive MS); 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, CIDP, and neuromyelitis optica spectrum disorder); and Teva Pharmaceuticals (two non-branded talks to patient groups about MS). RPL has presented several CME talks for companies with multiple sources of support (no direct payments to RBL). RPL has received clinical trial grants (no direct payments) for studies in myasthenia gravis (Alexion, Argenx, Ra Pharmaceuticals) and MS (Novartis, Teva, Genentech/Roche, Chugai). He has received royalties from Blackwell Press as an editors of a textbook International Neurology. RBL is an author of several papers cited in this topic.


Dr Robert Lisak would like to gratefully acknowledge Dr Andrea Corse and Dr Ami Mankodi, previous contributors to this topic. AC and AM declare that they have no competing interests.

Peer reviewers

Vern C. Juel, MD

Associate Professor of Medicine (Neurology)

Duke University




VCJ declares that he has no competing interests.

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