Thrombophilia and stroke.

Thrombophilia is defined as an enhanced tendency to form intravascular thrombi, which may be arterial or venous. Of the inherited thrombophilias, factor V Leiden and the prothrombin 20210 mutation have been associated with stroke, but this association is statistically significant only in children and adults under age 40. The risk of stroke in persons with these mutations is substantially increased by concomitant exposure to oral contraceptives. Hyperhomocystinemia is a major risk factor for stroke as well as Alzheimer's disease; persons with deficiencies of vitamin B12 or folic acid are especially vulnerable to these complications. Of the acquired thrombophilias, the antiphospholipid antibody syndrome is strongly associated with transient ischemic attacks, cerebral infarction, Sneddon syndrome, and dementia. The diagnosis of thrombophilia should be considered in stroke patients who are young, have a family history of thrombosis, suffer venous dural sinus thrombosis, or have recurrent strokes.