Cytokine-driven recurrent pericarditis in Down syndrome: Role of pericardial fluid analysis and cardiac magnetic resonance imaging.

Recurrent pericarditis is uncommon in children with Down syndrome (DS) and may present diagnostic challenges. We report the case of a child with DS who developed massive pericardial effusion with minimal systemic inflammatory markers. Pericardial fluid analysis revealed markedly elevated interleukin-6 levels, suggesting localized cytokine-driven inflammation. Cardiac magnetic resonance (CMR) imaging revealed limited subepicardial enhancement with preserved ventricular function, findings consistent with pericarditis and secondary myocardial involvement rather than primary myocarditis. Combination therapy with ibuprofen and colchicine resulted in sustained remission without recurrence. This case highlights that significant pericardial inflammation may occur in patients with DS despite minimal systemic inflammation, and CMR imaging may assist in disease activity assessment and therapeutic decision-making.