We describe a 23-year-old female patient with a history of systemic lupus erythematosus and pulmonary hypertension who developed a large pericardial effusion with cardiac tamponade. Invasive interventions such as pericardial window or pericardiectomy were ruled out because of the posterior localization of the effusion and high risk of general anesthesia in a patient with severe pulmonary hypertension. The patient received high-dose steroids intravenously with no response. A 5-day course of intravenous immunoglobulin resulted in gradual decrease of the pericardial effusion and resolution of cardiac tamponade within 2 weeks.