Arteriovenous malformation

Arteriovenous malformations (AVMs) are defects in the circulatory system . The circulatory system includes the arteries, veins, and capillaries and carries blood to and from the heart . An AVM is an abnormal connection of the arteries and veins. It interferes with the circulation of blood in an organ . AVMs can occur anywhere, but those located in the brain or spinal cord can have effects as are the seizures or sore head . However, most people with AVMs in the brainor the spinal cord experiences few major symptoms, if any.


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  • 1 Origin
  • 2 Classification
  • 3 Pathophysiology
  • 4 Symptoms
  • 5 Signs and tests
  • 6 Treatment
  • 7 Forecast
  • 8 Complications
  • 9 Source


The precise causes of its formation are unknown, although its origin may be hereditary (although a history where it has been inherited from generation to generation is rarely known) or due to trauma , although specialists differ in their origins. The only thing that is known with certainty is that this malformation is congenital; so one is born with it.


Arteriovenous malformations vary in size and shape. But we can classify them into:

  1. Paral arteriovenous malformations
  2. Subcortical arteriovenous malformations
  3. Ventricular arteriovenous malformations
  4. Combined arteriovenous malformations


Arteriovenous malformations are clinically expressed in response to an abnormal hemodynamic situation where there are high-flow, low-resistance vessels . In the absence of a normal capillary system, the tissue encompassed by AVM is poorly oxygenated , but thanks to the inherent plasticity of the embryonic nervous system , the normal brain function of that affected tissue often shifts to the adjacent parenchyma, which explains why AVMs are typically asymptomatic at birth.

The nest is the epicenter of the MAV and comprises a vascular conglomerate which description is maintained in the dispute to the vascular channels described as abnormal veins embryonic or normal veins arterialized by high pressure and flow. In relation to the nest, AVM can be divided into those with a single nest in which the vascular channels are all in some way interrelated, those that have more than one nest in adjacent areas but are individual components within the lesion and the diffuse ones that are pathologically disseminated arteries and veins between which a connection cannot be recognized angiographically.

The drainage venous may be superficial or deep and may involve single or multiple veins in dependence angioarchitecture in AVMs high flow vein main drain tends to undergo significant varicose dilations.


In about half of patients with arteriovenous malformations, early symptoms are those of an accident stroke caused by bleeding within the brain . Symptoms of a non-bleeding AVM include:

  1. Confusion
  2. Noises or ringing in the ear(also called pulsatile tinnitus)
  3. Sore head: can be in one area (localized) or whole head and in some cases can resemble a migraine
  4. Trouble walking
  5. Convulsions(seizures) of all types and severity
  6. Symptoms caused by pressure in one area of ​​the brain: blurred vision, decreased vision, double vision, muscle weakness anywhere on the body or face, and numbness anywhere on the body.

Signs and tests

A physical examination and a complete neurological evaluation are required, but they can be totally normal. Tests that can be used to diagnose AVM include:

  1. Cerebral angiography
  2. MRI of the head
  3. Electroencephalography(EEG)
  4. CT scanof the head
  5. Magnetic resonance angiography (MRA)


Finding the best treatment for AVM that is found on an x-ray or other imaging test, but is not causing any symptoms, can be difficult. The doctor will discuss with you:

  • The risk that the MAV will open (break). If this happens, there may be permanent brain damage.
  • The risk of any brain damage if you undergo one of the surgical treatments listed below.

The risk of prolonged bleeding is about 2 to 3% each year. Your doctor may discuss different factors that may increase your risk, including:

  • Current or planned pregnancies
  • Characteristics of AVM on an MRI or CT Scan
  • MAV size
  • Your age
  • Your symptoms

A bleeding arteriovenous malformation is an emergency. The goal of treatment is to prevent future complications by controlling seizures and bleeding and, if possible, eliminating AVM. Three surgical treatments are available and some of them are used together. The surgery cerebral open: removes abnormal connection through an opening in the skull . It must be done by a very experienced surgeon. Embolization (endovascular treatment):

  • A catheter is passed through a small incision in the groin into an artery and then into the small blood vesselsin the brain where the aneurysm is located.
  • gum-like substance is injected into the abnormal vessels to stop blood flow within the AVM and reduce the risk of bleeding . This may be the first option for some types of AVM or if surgery cannot be performed .

Another alternative is stereotactic radiosurgery:

  • This procedure releases highly focused radiation directly into the malformation area to cause scarring and size reduction.
  • It is particularly useful for small deep arteriovenous malformations in the brain that are difficult to remove by surgery.

If seizures do occur, antiseizure medications such as phenytoin are usually prescribed.


Approximately 10% of cases in which excessive bleeding ( hemorrhage ) is the first symptom are fatal. Some patients may have epileptic seizures and permanent brain and nervous system (neurological) problems . Arteriovenous malformations that do not cause symptoms when people are near or shortly after 50 years of age are more likely to remain stable and are rarely symptomatic.


  • Daño cerebral
  • Hemorragiaintracerebral
  • Dificultades en el lenguaje
  • Entumecimiento de cualquier parte de la cara o el cuerpo
  • Dolor de cabezapersistente
  • Crisis epiléptica (convulsiones)
  • Hemorragiasubaracnoidea
  • Cambios en la visión
  • Aguaen el cerebro (hidrocefalia)
  • Debilidad en parte del cuerpo

Las posibles complicaciones de una cirugía cerebral abierta abarcan:

  • Hinchazón del cerebro
  • Hemorragia
  • Crisis epiléptica
  • Accidente cerebrovascular


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