Localized ST Elevations and PR Depressions in Systemic Lupus Erythematosus Pericarditis: An Unusual Case Presentation.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with frequent cardiac involvement. A 49-year-old male with a 20-year history of SLE presented with a rash and lip swelling concerning for angioedema versus anaphylaxis. During bedside rounds, point-of-care-ultrasound (POCUS) revealed a small posterior pericardial effusion, prompting a formal transthoracic echocardiogram (TTE). He subsequently developed acute substernal chest pain with ECG findings of isolated ST elevations and PR depressions, in the inferior leads (II, III, and aVF). Despite concerns for acute coronary syndrome (ACS), the team was reassured by POCUS, TTE, and negative troponins. He was diagnosed with SLE-associated pericarditis and treated with NSAIDs, steroids, hydroxychloroquine, and methotrexate. This case highlights the importance of utilizing POCUS and physical examination skills to differentiate SLE-associated pericarditis from ACS, particularly when ECG findings present in a localized, non-diffuse pattern.