neurologic disorders
Brain Aneurysms
Introduction
Brain aneurysms are focal dilations in the cerebral arteries. In the United States, brain aneurysms occur in 3 to 5% of people. Brain aneurysms can occur at any age but are most common among people aged 30 to 60 years. They are more common among women than men. Common contributing factors for aneurysms may include Hereditary connective tissue disorders (eg, Ehlers-Danlos Syndromes , Family history of aneurysm (first-degree relative: parent, sibling, or child) Hypertension None Cigarette smoking Polysubstance abuse Occasionally, septic emboli cause mycotic aneurysms. Hypertension weakens the wall of the aneurysm by mechanical stress and causes vascular inflammation; both effects contribute to aneurysm rupture. Blood pressure control is important in preventing aneurysm rupture. Brain aneurysms are most often<2.5 cm in diameter and saccular (noncircumferential); sometimes they have one or more small, thin-walled, outpouchings (berry aneurysm). Most brain aneurysms occur along the middle or anterior cerebral arteries or the communicating branches of the circle of Willis, particularly at arterial bifurcations. Mycotic aneurysms usually develop distal to the first bifurcation of the arterial branches of the circle of Willis. 