Pericardial Effusion as the First Presentation of Systemic Lupus Erythematosus in a 22-Month-Old Infant: A Case Report and Literature Review.

Childhood-onset systemic lupus erythematosus (cSLE) is a multi-systemic, inflammatory autoimmune disease that affects many organs including the heart. Pericardial effusion as a primary manifestation of SLE in early infancy is very rare. It has been reported as the first symptom of SLE in adult and adolescent case reports only and the youngest reported case was a three-year-old. We report a case of a 22-month-old infant who had previously been healthy but presented with pericardial effusion and a reduced ejection fraction of 20%. She progressed to cardiogenic shock and acute renal failure and required invasive ventilation, inotropic support and temporary dialysis. She was diagnosed with SLE that was genetically confirmed as autosomal recessive SLE. Her condition improved significantly after starting SLE management with immunosuppression therapy. Pericardial effusion has resolved with medical therapy only and cardiac dysfunction has recovered. According to the available literature, this is the youngest reported case of SLE manifesting as pericardial effusion. This case highlights the importance of including SLE in the differential diagnosis for infants presenting with pericarditis, myocarditis, or pericardial effusion to guide early intervention and reduce risks associated with the disease.