Neonatal Deep Vein Thrombosis Reveals an Inferior Vena Cava Agenesis associated with Antithrombin Deficiency: A Case Report

Inferior vena cava (IVC) agenesis is a rare condition. It can be either congenital or acquired due to thrombotic events. It is a rare cause of deep vein thrombosis. We describe the case of a female newborn who presented with edema and cyanosis of the right lower limb. Lower extremity Doppler US showed thrombosis of the external iliac vein, common and superficial femoral right veins. Abdominal Doppler US suspected the absence of the infrarenal segment of IVC. CT abdominal angiography confirmed the agenesis of the infrarenal segment of IVC. Blood tests found an antithrombin level of 11% confirming the diagnosis of congenital antithrombin deficiency. Pharmacological measures were implemented to treat thrombosis since a surgical approach was not feasible.