Coronary Vasculitis in a Patient With IgG4RD and Possible EGPA Presenting With Acute Coronary Syndrome

BACKGROUND: IgG4-related disease (IgG4RD) is a systemic inflammatory disorder that can rarely affect the coronary arteries, leading to acute coronary syndrome (ACS). CASE SUMMARY: A 54-year-old man with IgG4RD and possible cytoplasmic antineutrophil cytoplasmic antibody vasculitis presented with exertional chest pain. An electrocardiogram showed T-wave inversions, and rising troponin levels confirmed ACS. Imaging revealed right coronary artery dissection and left circumflex aneurysmal remodeling, consistent with vasculitis-related coronary pathology. He was treated with antiplatelet therapy, corticosteroids, and rituximab, leading to symptom resolution and a significant reduction in IgG4 levels. DISCUSSION: This case highlights the complexity of ACS secondary to IgG4RD-associated vascular disease. Coronary involvement in IgG4RD remains under-recognized, necessitating a high index of suspicion and multimodal imaging for diagnosis. The successful use of rituximab underscores its potential in managing IgG4-related cardiovascular manifestations. TAKE-HOME MESSAGES: IgG4RD can present with ACS due to coronary vasculitis or dissection. Multidisciplinary collaboration and immunosuppressive therapy are key to optimal management.