Ischemic Syndromes Hemorrhagic Syndromes Arteriovenous Malformations Arteriovenous Malformations Congenital malformations of tangled, dilated blood vessels in which arterial afferents flow directly into venous efferents without the usual resistance of an intervening capillary bed. The result is progressively enlarging vasculature that can produce neurologic abnormalities by injuring adjacent neural tissue through compression, irritation, diversion of blood, or hemorrhage. Arteriovenous malformations are particularly likely to occur at the junction of cerebral arterial beds, most often within the cerebral parenchyma of the frontal-parietal region, the frontal lobe, the lateral cerebellum, or the overlying occipital lobe. These malformations produce three relatively distinct neurologic disorders. The only distinctive features of hemorrhages caused by these malformations are a tendency to be less neurologically devastating than those due to hypertensive or congenital aneurysm and a high rate of recurrence over the years.
Some patients have arterial bruits, detectable on the overlying cranial vault.
Resection is usually recommended for superficial malformations. Resection removes the risk of rebleeding and probably reduces the frequency or risk of seizures. Intravascular thrombosis via intra-arterial catheters or coagulation with focused proton beams may be effective in selected inoperable cases. All rights reserved.