label: Obstruction of the superior vena cava
label_lc: obstruction of the superior vena cava
description: "Blockage of blood flow through the superior vena cava (SVC). Because the venous drainage from the upper extremities, upper thorax and head is obstructed, SVC obstruction presents with symptoms related to engorgement of these areas. Both the degree of SVC compromise and the extent of collateral veins determine the varied clinical presentation, which can be as mild as slight facial and upper extremity edema or as dire as intracranial swelling, seizures, hemodynamic instability and tracheal obstruction."