arterio-venous malformations of the brain

A SMALL PRESENTATION TO 5TH YEAR MEDICAL STUDENTS AT THE UNIVERSITY OF JORDAN, AND TO THE 4TH YEAR STUDENTS AT THE HASHIMEYAH UNIVERSITY

WALID S. MAANI FRCSEd

PROFESSOR OF NEUROSURGERY

JORDAN UNIVERSITY MEDICAL SCHOOL AND HOSPITAL

ARTERIO-VENOUS MALFORMATION OF

THE BRAIN (AVM)

WHAT IS AN AVM?

• It is an abnormal connection between arteries and veins.

• It has a feeding artery or arteries

• A nidus

• A draining vein or veins

WHY DO AVMS OCCUR?

No body knows but they are

congenital and one is borne with

them, and they tend to grow by age.

WHEN DO THEY PRESENT?

They usually present early in life, around the

age of 10, but they can occur in older

patients up to 40 years of age. Once they

reach that age they mostly become stable.

HOW DO THEY PRESENT?

• They may be found incidentally when performing brain imaging

for other reasons.

• They may produce symptoms by “shunting” blood from its

normal course through capillaries.

• May cause pressure on the brain

• May induce epilepsy

• May rupture and produce intra cranial hemorrhage.

UNRUPTURED AVMS

• Being on the surface of the brain the may cause epilepsy.

• Shunting blood may lead to ischemia of certain part of the brain

and therefore brain damage.

• The abnormal blood vessels, being weak may develop

aneurysms.

• If large, they may compress the brain by sheer size and produce

neurological symptoms.

RUPTURED AVMS

• Rupture causes subarachnoid hemorrhage (SAH)

• It manifests it self by:

• Sudden headache

• Vomiting

• Deterioration of the level of consciousness

• Epilepsy

• Neurological manifestations

• Neck rigidity

DIAGNOSIS

In addition to clinical suspicion, the following is performed:

CEREBRAL ANGIOGRAPHY

CT ANGIOGRAPHY

MAGNETIC RESONANCE ARTERIOGRAPHY (MRA)

•

WHAT DO WE NEED FROM ANGIOGRAPHY?

• Demonstrating the AVM”s location and size

• Showing the feeding artery

• Showing the draining veins

TREATMENT

Factors influencing choice of treatment:

• The location of the AVM

• The size of the AVM

• Did the AVM bleed or not?

TREATMENT

Medical treatment is only reserved for

associated symptoms like treating seizures or

relieving headache.

TREATMENT

Definitive treatment is one of three:

• Surgical removal (resection)

• Occlusion by endovascular techniques

• Destruction by radiation (Gamma Knife)

SURGICAL REMOVAL

Usually indicated for superficial AVMs and those

which can be removed without harming the brain.

The feeding artery is occluded and the nidus

removed.

ENDOVASCULAR

• Could be used as an adjuvant to surgical resection; to

reduce the size of the AVM before surgery.

• Or, could be the sole treatment for deeply seated

AVMs, in which surgery is deemed harmful or

dangerous.

• Usually done by insetting beads or other material into

the lumen of the abnormality to occlude blood flow.

GAMMA KNIFE

• It is irradiation delivered by stereotactic procedure,

targeted at the AVMN.

• It usually require certain indications or prerequisites

regarding size and location.

• It certainly could be performed in emergency after

bleeding, because the irradiation need perhaps 2 years

to completely fibrose the AVM