Deficiency Of Antithrombin III (AT III) - Case Report and Review of the Literature.

Antithrombin III (AT III) is a plasmatic α-glicoprotein formed by a single peptidic chain. AT III inhibits thrombin (first target) and free Xa, IXa ,VIIa plasmatic factors. In plasma AT III is found under two forms: α-antithrombin and β-antithrombin. Deficiency of AT III represents a risk factor for thromboembolic disease. There are known both quantitative and qualitative AT III deficiencies. Incidence of AT III inherited deficiency is relative rare (1:10.000). Acquired deficiency of AT III is more frequent. The transmission of AT III deficiency is autosomal dominant with variable shield factor. Homozygous is incompatible with life (death immediately after birth). Thrombosis appears around the age of twenty years, and in 4-5 decades of life 2/3 of patients are symptomatics. Traumatisms, surgical interventions, estrogenic treatment, precipitated thrombotic complications. Obesity and dyslipidemic syndrome are risk factors. Thrombosis affects the venous system at these patients. Arterial thrombosis are less reported. The most frequent localisations are: the veins of the legs, mesenteric veins, cave veins, superficial periombilical veins. Treatment of AT III deficiency is: administration of AT III concentrates (with a plasmatic level by 80% from normal value) and heparinotherapy. The treatment with AT III concentrates is for patients which faced major surgical interventions, pregnant women with AT III deficiency. The women with AT III deficiency should avoid the utilisation of oral contraceptives.