Antithrombin Deficiency Clinical Presentation

Updated: Jul 29, 2022
  • Author: Drew H Barnes, MD; Chief Editor: Perumal Thiagarajan, MD  more...
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The clinical presentation of antithrombin deficiency (AT deficiency) depends on whether patients develop venous or arterial thrombosis and on the extent of damage to the particular organ. Patients with lower extremity deep venous thrombosis (DVT) present in the usual manner, with unilateral leg edema; pain in the calf, thigh, or groin; and limitation of movement due to the presence of pain.

Pulmonary embolism (PE) may manifest as dyspnea, onset of pleuritic chest pain, and, rarely, hemoptysis. PE is underdiagnosed in many patients with DVT, because DVT, PE, or both may be not be clinically apparent.

The most common thrombotic manifestations include lower extremity venous thromboembolism (VTE), with recurrent VTE being common. Thrombosis involving the abdominal veins and/or other organs results in different manifestations and includes the onset of vague abdominal pain; postprandial exacerbation of abdominal pain, bloating, diarrhea, and/or hematochezia when mesenteric veins are involved [55] ; and, sometimes, ascites with right upper abdominal pain if portal or hepatic vein thrombosis is present.

Thrombosis of the retinal vessels causes visual defects, whereas cerebral venous sinus or arterial thrombosis results in central nervous system (CNS) manifestations that are related to the location of the thrombus. Other sites of thrombosis include the inferior vena cava and renal, axillary, brachial, or pelvic veins. Arterial thrombosis as the first manifestation of AT deficiency is less common.

In patients with thrombosis, it is important to look for other precipitating factors, such as the use of oral contraceptives or hormone replacement therapy, trauma, [56] surgical procedures, pregnancy, and the postpartum state. Obtain a detailed family history, because an autosomal dominant pattern of inheritance may be evident. However, the lack of a positive family history does not exclude the presence of a thrombophilic mutation when a person is being evaluated for idiopathic or secondary thromboembolic disease.

Heparin causes an acquired reduction in AT levels. Several systemic diseases are also associated with reductions in AT.


Physical Examination

Physical findings depend upon the site of thrombosis. As indicated previously, VTE is much more common than arterial thrombotic disease.




Serious long-term morbidity can result from the following:

  • Venous and arterial thromboembolic events
  • Post-phlebitic syndrome due to extensive DVT
  • Recurrent VTE due to the discontinuation of oral anticoagulants
  • Sudden death due to the lack of prophylaxis in high-risk circumstances
  • Atypical site thrombosis such as  Budd-Chiari syndrome
  • Bowel ischemia due to mesenteric vein thrombosis