A severe case of Pembrolizumab-induced triad of myasthenic crisis, myocarditis, and anti-SSA myositis


  • Rola Mahmoud MD Saint Luke's Hospital of Kansas City https://orcid.org/0000-0003-0413-3532
  • Nathan K. McGraw MD Saint Luke's Hospital of Kansas City, University of Missouri-Kansas City https://orcid.org/0009-0003-8643-7202
  • Amy E. Poindexter APRN NP Saint Luke's Hospital of Kansas City
  • Gowri Warikoo University of Missouri-Kansas City




Myasthenia gravis, immune checkpoint inhibitors, myositis


A man in his late 70s presented with one week of progressive chest and muscle pain, generalized weakness, and fatigue. He received a single infusion of pembrolizumab three weeks prior as adjuvant immunotherapy for stage IIb malignant melanoma after undergoing wide local surgical excision. He was started on steroids for pembrolizumab-induced myositis and myocarditis. Symptoms progressed to include severe dyspnea, dysphagia and eyelid ptosis requiring tracheostomy and PEG tube placement. Serologic studies ultimately confirmed myasthenia gravis and anti-SSA myositis. 

He was emergently treated with plasma exchange, pyridostigmine, Intravenous Immunoglobulin (IVIG) and is making gradual improvement with physical therapy and oral prednisone taper.

We report a severe case of Pembrolizumab-induced triad of myasthenic crisis, myocarditis with myositis specific anti-SSA 52kD Ab IgG autoantibody for the first time. More studies are needed to assess the clinical significance and prognostic value of this autoantibody in patients presenting with Pembrolizumab-induced triad.


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Clinic and Case Reports

How to Cite

Mahmoud, R., McGraw , N. ., Poindexter, A. ., & Warikoo, G. (2023). A severe case of Pembrolizumab-induced triad of myasthenic crisis, myocarditis, and anti-SSA myositis. RRNMF Neuromuscular Journal, 4(4). https://doi.org/10.17161/rrnmf.v4i4.19844