Antithrombin III deficiency is a rare hereditary disorder that generally comes to light when a patient suffers recurrent venous thrombosis and pulmonary embolism. Inheritance is usually autosomal dominant, though a few recessive cases have been noted.^[1]

The disorder was first described by Egeberg in 1965.^[2]

The patients are treated with anticoagulants or, more rarely, with antithrombin concentrate.

In renal failure, especially nephrotic syndrome, antithrombin is lost in the urine, leading to a higher activity of Factor II and Factor X and in increased tendency to thrombosis.

Heparin Resistance

Pts with AT3 deficiency need higher doses of heparin. AT3 is known to slowly break up fibrin and factor X. When heparin binds to AT3, AT3 will break up fibrin and factor X faster. AT3 is not dependent on vitamin K so unlike warfarin, giving vitamin K will not reverse the effects of heparin.

Therefore, the treatment for these AT3 deficient patients is to add AT3 concentrates which will potentiate the heparin effect and reduce total heparin usage.

See also

• Antithrombin

References

External links

• Information on antithrombin from UIUC
• Non-profit advocacy group for patients and families with antithrombin deficiency

pt:Deficiência de antitrombina III