II. Epidemiology
- Rare cause of Thrombophilia
- First episode of thrombosis occurs ages 10-30 years
III. Pathophysiology
- 
                          Antithrombin III (AT3) is a Glycoprotein produced by the liver- Antithrombin III Deficiency (AT3 Deficiency) is an inherited Autosomal Dominant trait (or may be acquired)
- Heterozygous AT3 Deficiency patients have 25-50% AT3 functional levels
 
- Antithrombin III (AT3) normally inhibits clotting, Coagulation Factors (enhanced by Heparin)
- Antithrombin III Deficiency results in Thrombophilia
IV. Causes
- Inherited Antithrombin III Deficiency (most common)
- Acquired Causes- Liver Failure
- Malnutrition
- Nephrotic Syndrome (AnticoagulationProtein loss including AT3)
 
V. Labs
- Functional level Antithrombin III
VI. Management
VII. Complications
- Recurrent Miscarriage
- 
                          Venous Thromboembolism (DVT, PE)- Up to 50% lifetime Prevalence (esp. in teen years during hormonal increases)
 
VIII. References
- Jean-Louis and Sethuraman (2023) Crit Dec Emerg Med 37(7): 4-11
