Cardiac tamponade presenting as an apparent life-threatening event.

The initial emergency department (ED) evaluation of infants with an apparent life-threatening event (ALTE) often fails to identify a definitive cause for the event. Many children that present with an ALTE appear normal by the time they arrive to the ED. These factors can desensitize clinicians into prematurely discounting serious underlying causes of the ALTE or being less prompt in their evaluation of these patients. We present the case of a young infant who presented to an ED with an ALTE resulting from cardiac tamponade. Cardiac tamponade has not been reported as an underlying cause of infants presenting to the ED with an ALTE. Previously reported cases of cardiac tamponade in children have occurred as a complication of malignancies, cardiac surgery, trauma, infections, central venous catheter placement, rheumatologic, and autoimmune diseases. This case should serve as a reminder to clinicians to maintain a broad differential diagnosis and promptly evaluate all infants presenting with an ALTE.