Arteriovenous malformation
Channel: all the knowledge of the universe PRINCIPIA
Date: 2021-12-05

Arteriovenous malformation, by Wikipedia https://en.wikipedia.org/wiki?curid=3135 / CC BY SA 3.0

#Congenital_vascular_defects
#Gross_pathology
#RASopathies
Arteriovenous malformation is an abnormal connection between arteries and veins, bypassing the capillary system.
This vascular anomaly is widely known because of its occurrence in the central nervous system （usually cerebral AVM）, but can appear in any location.
Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems.
AVMs are usually congenital and belong to the RASopathies.
The genetic transmission patterns of AVMs are incomplete, but there are known genetic mutations （for instance in the epithelial line, tumor suppressor PTEN gene） which can lead to an increased occurrence throughout the body.
Symptoms of AVM vary according to the location of the malformation.
Roughly 88% of people with an AVM are asymptomatic; often the malformation is discovered as part of an autopsy or during treatment of an unrelated disorder （called in medicine an "incidental finding"）; in rare cases,
its expansion or a micro-bleed from an AVM in the brain can cause epilepsy, neurological deficit, or pain.
The most general symptoms of a cerebral AVM include headaches and epileptic seizures, with more specific symptoms occurring that normally depend on the location of the malformation and the individual.
Such possible symptoms include: Cerebral AVMs may present themselves in a number of different ways: Pulmonary arteriovenous malformations are abnormal communications between the veins and arteries of the pulmonary circulation,
leading to a right-to-left blood shunt.
They have no symptoms in up to 29% of all cases, however they can give rise to serious complications including hemorrhage, and infection.
They are most commonly associated with hereditary hemorrhagic telangiectasia.
Can occur due to autosomal dominant diseases, such as hereditary hemorrhagic telangiectasia.
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