An Exceedingly Rare Case of Antithrombin III Deficiency and Catastrophic Antiphospholipid-Like Disease

Abstract

Antithrombin III (AT III) is a critical component of the coagulation cascade that functions primarily to inhibit activated coagulation factors IIa and Xa. AT III deficiency is a disorder that predisposes patients to thromboemboli. Antiphospholipid syndrome (APS) is an autoimmune disorder that predisposes patients to vascular and microvascular thrombosis, which can often be devastating and lead to multiorgan involvement. The mainstay of treatment for both conditions involves the use of lifetime vitamin K antagonists. Recent studies suggest that patients with APS refractory to warfarin therapy may benefit from the addition of aspirin, statin, or hydroxychloroquine; low weight molecular heparin; or a combination regimen. Studies have also suggested that patients with AT III deficiency refractory to warfarin therapy may see improvement with use of a novel oral anticoagulant. This case report describes the recurrent hospitalizations of a 45-year-old patient who presented with multiorgan thrombosis involving the descending aorta, deep lower extremity veins, superior mesenteric artery and artery of the brain. This led to mesenteric ischemia, limb necrosis and a subacute frontal cortex infarct. Initial anticoagulation therapy was refractory to the use of warfarin. Enoxaparin therapy was initiated, resulting in no further thrombotic events. Clinicians should consider poor gastrointestinal absorption of warfarin in patients who fail to reach therapeutic anticoagulation goals. In addition, a thorough workup for hereditary and acquired thrombophilias should be performed in patients who present with recurrent thromboemboli, as these disorders increase the risk of poor patient outcomes if left untreated. J Med Cases. 2021;12(7):262-266 doi: https://doi.org/10.14740/jmc3689