Abstract
A 36-year-old Hispanic woman with a history of systemic lupus erythaematosus (SLE) in remission presented with progressive dyspnoea, bilateral leg swelling and increasing fatigue with rapid weight gain over the past few months. Her physical examination showed mildly tender thyromegaly and pericardial rub. Investigations showed new onset marked hypothyroidism as well as an active lupus serology with echocardiogram confirming severe pericardial effusion and a tamponade phenomenon. Urgent pericardiocentesis relieved her acute symptoms, and prompt treatment with thyroxine replacement and immunosuppression for lupus disease was initiated. Pericardial fluid analysis remained negative for any malignancy and/or infection/s. The patient had a gradual and consistent improvement with this treatment. She was discharged and appeared to be clinically stable at subsequent follow-up visits. However, the case remained a diagnostic dilemma over whether the tamponade was being driven by hypothyroidism versus lupus, leaving us with an opportunity to explore further.