14 July 2026
: Case report 
Single-Dose Nivolumab as a Trigger of Myocarditis, Myositis, and Myasthenia Gravis Overlap Syndrome With Late Cardiac Death Despite Initial Recovery: A Case Report
Unusual or unexpected effect of treatment, Rare disease, Adverse events of drug therapy
Deepika Beereddy ABCDEF 1*, Durga Naga Malleswara Rao Jonnalagadda ABCE 1, Shobha Mandal CDE 2, Jieyu Zhang B 1DOI: 10.12659/AJCR.953173
Am J Case Rep 2026; 27:e953173
Table 2 Chronological summary of clinical presentation, management, and outcome in a patient with immune checkpoint inhibitor-associated myocarditis, myositis, and myasthenia gravis overlap syndrome.
| Time point | Clinical event |
|---|---|
| ~2 months before admission | Wide local excision of left shoulder for stage IIIC malignant melanoma |
| ~4 weeks before admission | First dose of adjuvant nivolumab administered |
| 7 days before admission | Progressive generalized weakness and gait instability began |
| 4 days before admission | Dark-colored urine noted |
| Day 0 (admission) | Presented with weakness and gait impairment; markedly elevated troponin, CK, and transaminases; ECG showed right bundle branch block; high-dose IV methylprednisolone initiated for suspected ICI-associated myocarditis and myositis |
| Hospital Day 1–2 | Troponin, CK, and liver enzymes began to improve |
| Hospital Day 3 | Development of diplopia and bilateral ptosis; concern for myasthenia gravis; new oxygen requirement |
| Hospital Day 4 | Neurologic evaluation demonstrated bulbar weakness; plasmapheresis initiated |
| Hospital Day 6 | Completed 6 days of high-dose IV methylprednisolone (1 g/day); transitioned to weight-based dosing of IV methylprednisolone (2 mg/kg/day) |
| Hospital Day 9 | Completed 3 sessions of plasmapheresis; Pyridostigmine 60 mg every 8 hours was started |
| Hospital Day 12 | Completed 5 sessions of plasmapheresis with improvement in muscle strength and ocular symptoms |
| Hospital Day 16 | Discharged on oral prednisone (1 mg/kg/day) and pyridostigmine (90 mg every 8 hours) |
| 12 days after discharge | Nivolumab permanently discontinued at outpatient follow-up with oncology |
| ~2.5 weeks after discharge | Out-of-hospital cardiac arrest with prolonged downtime (~34 minutes); death following transition to comfort-focused care |
| ICI, immune checkpoint inhibitor; ECG, electrocardiogram; CK, creatine kinase; IV, intravenous. Hospital Day 0 denotes the day of hospital admission; subsequent hospital days are referenced relative to admission. All medication doses are reported as administered during hospitalization unless otherwise specified. | |