II. Epidemiology

  1. Rare cause of Thrombophilia
  2. First episode of thrombosis occurs ages 10-30 years

III. Pathophysiology

  1. Antithrombin III (AT3) is a Glycoprotein produced by the liver
    1. Antithrombin III Deficiency (AT3 Deficiency) is an inherited Autosomal Dominant trait (or may be acquired)
    2. Heterozygous AT3 Deficiency patients have 25-50% AT3 functional levels
  2. Antithrombin III (AT3) normally inhibits clotting, Coagulation Factors (enhanced by Heparin)
    1. Factor IXa
    2. Factor Xa
    3. Factor XIa
    4. Factor XIIa
    5. Thrombin
  3. Antithrombin III Deficiency results in Thrombophilia
    1. Deep Vein Thrombosis
    2. Pulmonary Embolism

IV. Causes

  1. Inherited Antithrombin III Deficiency (most common)
  2. Acquired Causes
    1. Liver Failure
    2. Malnutrition
    3. Nephrotic Syndrome (AnticoagulationProtein loss including AT3)

V. Labs

  1. Functional level Antithrombin III

VII. Complications

  1. Recurrent Miscarriage
  2. Venous Thromboembolism (DVT, PE)
    1. Up to 50% lifetime Prevalence (esp. in teen years during hormonal increases)

VIII. References

  1. Jean-Louis and Sethuraman (2023) Crit Dec Emerg Med 37(7): 4-11

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Ontology: Antithrombin III Deficiency (C0272375)

Definition (NCI) A rare disorder characterized by the presence of low levels of antithrombin III which prohibits the formation of blood clots. It may be inherited, usually in an autosomal dominant pattern, or acquired. It may lead to venous thrombosis and pulmonary embolism.
Definition (MSH) An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.
Concepts Disease or Syndrome (T047)
MSH D020152
ICD10 D68.59
SnomedCT 36351005
English AT def - Antithrombin defi, Antithrombin III Deficiency, ANTITHROMBIN III DEFIC, DEFIC ANTITHROMBIN III, ANTITHROMBIN 3 DEFIC, Antithrombin 3 Deficiencies, Antithrombin 3 Deficiency, Deficiencies, Antithrombin 3, Deficiency, Antithrombin 3, Antithrombin III Deficiencies, Deficiencies, Antithrombin III, Deficiency, Antithrombin III, AT-III deficiency, antithrombin III deficiency, antithrombin III deficiency (diagnosis), Antithombin III deficiency, ANTITHROMBIN III DEFICIENCY, Antithrombin III Deficiency [Disease/Finding], antithrombin 3 deficiency, antithrombin deficiency, antithrombin deficiencies, antithrombin iii deficiency, AT3D, THROMBOPHILIA DUE TO ANTITHROMBIN III DEFICIENCY, THPH7, Antithrombin III deficiency, AT deficiency - Antithrombin deficiency, Antithrombin deficiency, Antithrombin III deficiency (disorder)
Japanese アンチトロンビンIII欠乏症, アンチトロンビン3ケツボウショウ, Antithrombin III欠損症, アンチトロンビンIII欠損症, AT3欠損症, アンチトロンビン3欠乏症, アンチトロンビン3欠損症, アンチトロンビンIII欠乏症
Swedish Antitrombin III-brist
Czech antithrombin III - nedostatek, Deficit antitrombinu III
Finnish Antitrombiini III:n puutos
Russian ANTITROMBINA III NEDOSTATOCHNOST', АНТИТРОМБИНА III НЕДОСТАТОЧНОСТЬ
Polish Niedobór antytrombiny III
Hungarian Antithrombin-III-hiány
Norwegian Antitrombin-III-mangel, Antitrombin III-mangel, Antitrombin-3-mangel, Antitrombin 3-mangel
Spanish deficiencia de antitrombina III (trastorno), deficiencia de antitrombina III, Déficit de antitrombina III, Deficiencia de Antitrombina III
Portuguese Carência de antitrombina III, Deficiência de Antitrombina III
Dutch antitrombine III-deficiëntie, Antitrombine-III-deficiëntie, Deficiëntie, antitrombine-III-
French Déficit en antithrombine III, Déficit en AT III, Déficit en AT3, Déficit en antithrombine 3
German Antithrombin-III-Mangel
Italian Deficit di antitrombina III