AVM (Arteriovenous Malformation)

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.

Signs and symptoms

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:

  • Difficulties with movement coordination, including muscle weakness and even paralysis;
  • Vertigo (dizziness);
  • Difficulties of speech (dysarthria) and communication, such as aphasia;
  • Difficulties with everyday activities, such as apraxia;
  • Abnormal sensations (numbness, tingling, or spontaneous pain);
  • Memory and thought-related problems, such as confusion, dementia or hallucinations.