Myasthenia gravis

Last reviewed: 2 Sep 2023
Last updated: 05 Sep 2023



History and exam

Key diagnostic factors

  • muscle strength 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


myasthenic crisis


mild to moderate disease (class I to III)

severe (class IV or V) or refractory disease



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 a Data and Safety Monitoring Board Member for the COUR myasthenia gravis clinical trial. RPL is a site principal investigator for clinical trials and a co-author for the clinical trial reports for myasthenia gravis therapies for Alexion, Argenx, and UCB Ra. RPL's institution receives payment for the time spent on these clinical trials. RPL has received book royalties from Oxford University Press and Blackstone, and has carried out consultancy work for Avilar.


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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