[Brain stem ischemia in a boy with resistance to C activated protein and elevated lipoprotein A].

Introduction: Activated protein C resistance is the most common hereditary coagulation abnormality. In the majority of cases it results from a point mutation Arg506-->Gln of the factor V gene, and characterized by a poor anticoagulant response to activated protein C.

Clinical Case: We report the clinical case of a 6-year-old obese boy, who presented with acute hemiparesis. A cerebral MRI revealed an area of infarction in the left hemiprotuberance. Further investigation identified activated protein C resistance (heterozygosity for factor V Leiden) and elevation in lipoprotein (a). His mother also had factor V Leiden mutation. Prophylaxis with acetylsalicylic acid was instituted with favorable evolution.

Conclusions: This mutation, isolated, is usually asymptomatic, unless other risk factors coexist. Although venous thromboembolism seems to be the main clinical manifestation, recent reports consider that activated protein C resistance is also a risk factor for arterial thrombosis and stroke in children. We reinforce the need for systematic and thorough evaluation of etiology and risk factors in cases of stroke in children.