An Atypical Initial Presentation of Systemic Lupus Erythematous With Bilateral Lower Extremity Edema and Unilateral Pleural Effusion.

Systemic lupus erythematosus (SLE) is an autoimmune condition more commonly observed in women of childbearing age. The most commonly reported initial presentations were fatigue, arthritis, and skin manifestations. However, due to the involvement of a variety of organs, diagnosis remains a challenge for physicians. Our patient is a 48-year-old lady who presented with severe bilateral lower extremity edema with non-resolving right lower lobe pneumonia and ipsilateral exudative pleural effusion. Her leg swelling was not responding to diuretics, and her pneumonia was not improving following a course of antibiotics. This unusual presentation prompted an autoimmune workup, which later revealed a diagnosis of SLE with class 5 lupus nephritis. Pleuritis, exudative pleural effusion, and lupus nephritis have been associated with autoimmune disorders in the literature, but this is an uncommon initial presentation in SLE without other clinical manifestations. Our case report highlights the challenges in the diagnosis of an atypical case of SLE and the need to maintain high clinical suspicion for SLE, especially in female patients with multiorgan involvement.