Cerebral arteriovenous malformation

Venous blockage is a serious disease, but it usually occurs in the summer solstice. If the brain has venous blockage, it is very similar to cerebral infarction. This phenomenon is particularly likely to cause hemiplegia and headaches. Therefore, timely treatment is necessary to prevent blood vessel deformation. So what should be done with cerebral arteriovenous malformations?

Cerebral arteriovenous malformation is the most common malformation caused by abnormal development of cerebral blood vessels. It accounts for more than 90% of cerebrovascular malformations. Abnormal blood vessels are composed of arteries and veins, some of which include aneurysms and venous aneurysms. Brain arteriovenous malformations have supplying arteries and draining veins, and their sizes and shapes vary. It can occur in any part of the brain, and the distribution of lesions on the left and right sides is basically equal. More than 90% are located on the tentorium, while most are distributed in the cerebral cortex, accounting for about 70% of supratentorial lesions. Among them, the parietal, frontal and temporal lobes are more common, and the occipital lobe is slightly less common.

Cerebral arteriovenous malformation

Cerebral arteriovenous malformations[1] are the most common malformations caused by abnormal development of cerebral blood vessels. It accounts for more than 90% of cerebrovascular malformations. Abnormal blood vessels are composed of arteries and veins, some of which include aneurysms and venous aneurysms. Brain arteriovenous malformations have supplying arteries and draining veins, and their sizes and shapes vary. It can occur in any part of the brain, and the distribution of lesions on the left and right sides is basically equal. More than 90% are located on the tentorium, while most are distributed in the cerebral cortex, accounting for about 70% of supratentorial lesions. Among them, the parietal, frontal and temporal lobes are more common, and the occipital lobe is slightly less common.

Brain arteriovenous malformation

Cerebral arteriovenous malformations are primarily developmental disorders of cerebral blood vessels. During the third embryonic week, the primitive cerebral vascular network begins to differentiate into arteries and veins and into capillary networks between arteries and veins. The primitive arteries and veins are arranged in parallel and closely adjacent to each other. If the normal development of cerebral blood vessels is obstructed at this time, direct communication is formed between the arteries and veins without a capillary network separating them, thus forming an arteriovenous malformation. Some people have found that the arteries in arteriovenous malformations have already matured, while the venous endothelial cells remain at the embryonic level in morphology, and believe that arteriovenous malformations are caused by venous developmental disorders.

Arteriovenous malformation is composed of a mass of arteries, veins, and arterialized venous (arteriovenous fistula)-like blood vessels. The arteries communicate directly with the veins without capillaries in between. Due to the blood stealing from the abnormal blood vessels, the blood supply to the surrounding brain tissue is reduced, resulting in blood steal symptoms. Steal blood is caused by arteriovenous fistula and is easily shown on cerebral angiography.

Symptoms and signs

Small AVMs are often asymptomatic, even when they are quite large. Unless it is discovered after bleeding or causing epilepsy, most of the time it is diagnosed after bleeding, and the second is discovered during the search for the cause of epilepsy. Some are discovered due to long-term, intractable headaches. The symptoms depend on the location, size, and whether there is bleeding or ischemia of the arteriovenous malformation. So

(1) Bleeding: This is the most common symptom of intracranial arteriovenous malformation, and more than half of the cases occur between the ages of 16 and 35. Bleeding is not related to the season and usually occurs during normal activities. Increased risk of bleeding during pregnancy.

(2) Epilepsy: It may occur during intracranial hemorrhage or alone. The reasons for epilepsy in patients with arteriovenous malformations are: arteriovenous shunt causing local cerebral ischemia and glial changes in adjacent brain tissue; and the ignition effect of temporal lobe arteriovenous malformation.

(3) Headache: Most of them are the result of intracranial hemorrhage. In addition, about 43% of patients have persistent or recurrent headaches before bleeding, which are often intractable headaches.

(4) Focal symptoms: Depends on the location of vascular malformation, hematoma compression, cerebral blood circulation disorder and brain atrophy area.

(5) Other symptoms: intracranial vascular murmurs, mental symptoms, exophthalmos, vascular murmurs, secondary intracranial hypertension, diplopia, heart failure, etc.