Purpose: Introduction: Anti-tumor necrosis factor-alpha agents are commonly used in the treatment of Crohn's disease. But treatment may be complicated by adverse reactions. We report a rare case of cardiac tamponade in a patient with Crohn's disease who was started on infliximab. Case Report: A 79-year-old man was admitted to the intensive care unit with chest pain and dizziness. On arrival, he was hypotensive with a blood pressure of 80/50 mmHg. Dopamine and dobutamine were started for presumed cardiogenic shock. On examination, he was sweaty and clammy. Heart sounds were distant and chest was clear to auscultation. His past history was significant for Crohn's disease affecting the colon and distal ileum and coronary artery disease. He was on aspirin, clopidogrel, atorvastatin, 5-amino salicylic acid (Asacol), and most recently infliximab. He had received two doses at 5 mg/kg. A chest x-ray revealed subtle cardiomegaly. A V/Q scan showed a low probability of pulmonary embolism. His echocardiogram showed moderate pericardial effusion. Cardiac catheterization revealed a diastolic equalization of pressures on catheterization at 17 mm Hg which indicated cardiac tamponade and prompted urgent pericardiocentesis. 450 ml of blood stained fluid was removed. Patient's symptoms and the need for ionotropic support immediately resolved. Pericardial fluid analysis showed inflammatory picture. Fluid gram stain and culture were negative. ANA and anti-dsDNA were negative. The patient was never rechallenged with infliximab in view of the severity of the presumed reaction. Discussion: Pericardial effusions and pericarditis have been reported in patients with rheumatoid arthritis and Crohn's disease treated with anti-TNF-alpha agents. Recurrent pericarditis has been reported in a patient with multiple sclerosis treated with natalizumab. Infective pericarditis may also develop in patients on anti-TNFalpha therapy. In conclusion, we report a rare case of cardiac tamponade in a patient with Crohn's disease treated with infliximab. This serious complication highlights an uncommon reaction to anti-TNF-alpha therapy and emphasizes the need to be vigilant for adverse events.Figure: Pericardial effusion on echocardiogram.