Thymoma-Associated Myasthenia Gravis With Myocarditis

Area of Science:

• Cardiology
• Neurology
• Immunology

Background:

• Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular junctions.
• Myocarditis, inflammation of the heart muscle, can be a rare complication of MG.

Observation:

• A patient presented with symptoms mimicking ST-segment elevation myocardial infarction (STEMI) but had normal coronary arteries.
• A mediastinal mass suspicious for thymoma was identified.
• Neurological decline led to MG diagnosis confirmed by EMG/NCS and RNS.
• Cardiac MRI revealed diffuse myocardial edema, severe LV dysfunction, and LGE.

Findings:

• The patient was diagnosed with thymoma-associated MG complicated by myocarditis.
• Successful treatment was achieved with immunosuppressive therapy.

Implications:

• This case underscores the critical association between myocarditis and MG.
• Cardiac evaluation is essential for MG patients presenting with cardiac symptoms, ECG changes, or elevated cardiac biomarkers.
• Early recognition and management of this rare autoimmune manifestation can improve patient outcomes.