ABCDE of complex pericarditis cases.

Pericarditis is the most frequent manifestation of pericardial disease and accounts for up to 5% of emergency department visits for chest pain. Although traditionally considered a benign and self-limited condition, it is a heterogeneous syndrome with a broad aetiological spectrum and potentially significant morbidity. While mortality is low, the burden of complications like recurrent disease, cardiac tamponade or constrictive pericarditis, and the frequent need for hospitalisation underscore its clinical relevance. The growing availability of multimodality imaging and the publication of updated international guidelines in 2025 have recently renewed attention to pericardial diseases, refining diagnostic criteria, risk stratification and therapeutic approaches. In high-income settings, idiopathic or presumed viral pericarditis remains the most common presentation. However, a substantial proportion of patients harbour alternative aetiologies that carry distinct prognostic implications and require tailored diagnostic and management strategies. In this review, we use the ABCDE mnemonic as a pragmatic framework to highlight five clinically important and often under-recognised forms of pericardial disease. Pericarditis associated with autoimmune and systemic inflammatory diseases is typically characterised by recurrent or refractory inflammatory courses and frequent extracardiac involvement. Bacterial pericarditis, although rare, represents a life-threatening condition requiring rapid aetiological identification and aggressive therapy. Cancer-related pericardial disease often presents with large pericardial effusions or cardiac tamponade and is associated with a poor prognosis largely determined by the underlying malignancy. Damage-related and drug-related pericarditis encompasses postcardiac injury syndromes and pharmacological toxicity. Finally, endocrine and metabolic disorders, including uraemia, hypothyroidism and infiltrative conditions such as amyloidosis, are associated with pericardial disease that manifests with atypical features and effusion. Early recognition of these entities is critical, as management extends beyond standard anti-inflammatory therapy and often requires correction of the underlying cause and close multidisciplinary collaboration. This ABCDE approach can aid clinicians in identifying these uncommon high-risk forms of pericarditis and optimising patient-centred care.