Facial Swelling Mimicking Anaphylaxis: A Case of Superior Vena Cava Syndrome in the Emergency Department.

Superior vena cava (SVC) syndrome represents clinical manifestations from obstruction of the SVC. It is an uncommon medical emergency that is commonly missed. SVC obstruction is usually caused by extraluminal compression by an intrathoracic mass or intraluminal obstruction from a thrombus. The latter is more common in patients with indwelling central venous catheters and pacemaker leads. Here, we present the case of a 53-year-old woman who presented to the emergency department (ED) with clinical features which were initially diagnosed as anaphylaxis and subsequently diagnosed as a case of SVC syndrome. In this case, diagnostic challenges in the ED and the potential role of cognitive bias are highlighted. In addition, we discuss the clinical manifestations and management of SVC syndrome.