The condition of tangled abnormal blood vessels which connect the veins and arteries in the brain is called Brain AVM or brain arteriovenous malformation.
Arteries carry oxygenated blood from the heart towards the brain while the veins bring the de-oxygenated blood from the brain to the heart and lungs. The disruption of this life-sustaining process is caused by a Brain AVM or brain arteriovenous malformation.
The tangling of blood vessels or an arteriovenous malformation can occur anywhere in the body, but is prominently found in the brain or spinal cord. The occurrence of a Brain AVM or brain arteriovenous malformation is rare and hardly affects 1% of the entire population.
The reason for occurrence of an Brain AVM or brain arteriovenous malformation is still unclear. It generally occurs during birth itself. But in few cases, it may form in the later stages of life. It has less chances of genetic inheritance.
Few people affected with Brain AVM or brain arteriovenous malformation have headaches and seizures as symptoms. But the presence of tangled blood vessels is usually detected after a scan or after brain hemorrhage i.e. rupturing of blood vessels in the brain.
Brain AVM or brain arteriovenous malformation can often be completely cured after it’s diagnosed to prevent further damage & complications to brain.
Signs and Symptoms of Brain AVM or Brain Arteriovenous Malformation
It is difficult to detect a Brain AVM or brain arteriovenous malformation unless a blood vessel rupture results in bleeding or hemorrhage inside the brain. A hemorrhage is the initial sign of majority of all Brain AVM or brain arteriovenous malformation.
Few people also experience other symptoms apart from blood oozing in the brain as an indication of Brain AVM or brain arteriovenous malformation.
Apart from hemorrhage, other indications of a Brain AVM or brain arteriovenous malformation are:
- Seizure
- Throbbing pain in a concentrated region of the head or headache
- Weakness in the muscular system or numb feeling in any part of the body.
Few people may further experience deliberate neurological signs based on the region of an Brain AVM or brain arteriovenous malformation like:
- Extreme headache
- Numb feeling, paralysis or weakening of muscles
- Loss of vision
- Complications in speaking
- Bewilderedness and failure to get the idea of what others are saying
- Unstable feeling.
The symptoms may arise at early ages, but surface at the age of 10-40 years. Brain AVM or brain arteriovenous malformation may gradually result in damaging a brain tissue over a period of time. The after-effects of AVM slowly develop and show effect in middle ages.
Brain AVM or brain arteriovenous malformation shows severe effects in pregnant women as they have variations in volume of blood and pressure of its flow.
Vein of Galen defect is one of the most severe types of Brain AVM or brain arteriovenous malformation. Its symptoms surface as soon as the infant is born. The major blood vessels present in the infant’s brain become bulged out because of fluid build-up in them and results in swelling of head. The symptoms of Vein of Galen defect are swollen veins which can be seen on the scalp, seizure, congestive heart failure.
Consulting the Doctor for Brain AVM or Brain Arteriovenous Malformation
It is recommended to rush to a shrink if any signs of Brain AVM or brain arteriovenous malformation surface. The signs include seizure, throbbing pain or headache, weakness etc. A brain hemorrhage is alarming and may affect one’s life. This condition requires medical emergency treatment.
Causes of Brain AVM or Brain Arteriovenous Malformation
Reasons or causes of Brain AVM or brain arteriovenous malformation are unknown, but research studies indicate that a Brain AVM or brain arteriovenous malformation is developed mostly during pregnancy.
Typically, heart sends oxygenated blood to the brain through arteries and arteries further branch out into capillaries or smaller blood vessels. The capillaries pass over the oxygen through their pores in the walls to the brain.
The deoxygenated blood returns from smaller blood vessels to larger veins. These veins send back oxygen-depleted blood to the heart and oxygen is supplied to it through lungs.
In a Brain AVM or brain arteriovenous malformation, there is insufficiency or lack of support from capillaries and veins in depositing and collecting blood.
Risk Factors for Brain AVM or Brain Arteriovenous Malformation
The Brain AVM or brain arteriovenous malformation can occur to any person but some factors possess serious threat:
- Brain AVM or brain arteriovenous malformations are more common in male population than the female population.
- Although chances of genetic hereditary or passing on this to the next generation are less, it is still possible.
Complications of Brain AVM or Brain Arteriovenous Malformation
Complications pertaining because of Brain AVM or brain arteriovenous malformation are:
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Brain hemorrhage: Arteriovenous Malformation causes extreme pressure to be exerted on the walls of damaged veins and arteries, resulting in weakening of them. This in turn results in a rupture of the capillaries and oozing blood in the brain.
The risks of brain hemorrhage ranges from 1-2% every year. Also, the risk linked with a brain hemorrhage is high for some type of AVM’s.
Few types of blood spilling or hemorrhage linked with AVM which are not surfaced and they will not be detected. It is because these type of AVM’s are passive and do not cause extensive damage to the brain. But they become a threat to life at times.
Arteriovenous Malformation in the brain accounts to two percent of all the brain hemorrhages occurred. It mainly affects kids and young adults.
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Decrease in oxygen supply to brain: As a result of a Brain AVM or brain arteriovenous malformation, the blood flow deviates from capillaries and flows straight from arteries to veins. The flow of blood rapidly through the bypassed route cannot be decelerated by capillaries.
The rapid flow of blood results in decreased supply of oxygen to the encompassed brain tissue. As a result, the tissues in the brain diminish or deteriorate due to the lack of oxygen supply. It causes breakdown, brain strokes, numb feeling, and loss of vision or dizziness.
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Weak or thin arteries and veins: Brain AVM or brain arteriovenous malformation exerts high pressure on the small and thin capillaries and weaker blood vessels. This results in a fluid build-up and makes the blood vessels more vulnerable to fissures.
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Catastrophe in the brain: When a person grows, the body will deploy more blood vessels to provide blood to the fast flowing Brain AVM or brain arteriovenous malformation. This in turn results in the increased size of some AVM’s or exerts pressure on some parts of the brain. Thus a protective fluid around the brain hemisphere is prevented from flowing freely.
A fluid build-up may result in pushing the brain tissues against the skull. It is scientifically known as hydrocephalus.
Tests to Diagnose Brain AVM or Brain Arteriovenous Malformation
To determine a Brain AVM or brain arteriovenous malformation, the neurologist will conduct physical tests and analyze your signs and symptoms.
Imaging tests may be done to the brain. It is done by radiologists who have hands on experience on brain imaging. The patient may be subjected to more than one test to determine the intensity of Brain AVM or brain arteriovenous malformation.
Few tests to determine a Brain AVM or brain arteriovenous malformation are:
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Cerebral Arteriography for Brain AVM or Brain Arteriovenous Malformation
It is the most precise test to determine Brain AVM or brain arteriovenous malformation. This test will reveal the region where an AVM has occurred and its characteristics surrounding the blood vessels supplying blood to the brain. This helps in deciding the treatments to be given.
A catheter or a lean thin tube is inserted into an artery by the doctor. This catheter gives details about your brain AVM with the aid of X-ray imaging technique. A dye is injected by the shrink to make the affected blood vessels visible in the X-ray imaging.
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CT-Scan for Brain AVM or Brain Arteriovenous Malformation
Computer tomography scan uses a set of X-rays to form an accurate description of detailed cross-sectional image in the brain. A dye is injected into the vein through an intravenous tube by the doctor. This dye helps in viewing the arteries supporting AVM and veins emptying the AVM in high detail in a CT angiogram.
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MRI for Brain AVM or Brain Arteriovenous Malformation
MRI or Magnetic Resonance Imaging makes use of high power magnets to get a precise image of the brain. MRI gives accurate results than a CT scan and can indicate the changes occurred in the brain due to an AVM, in greater detail. MRI also gives more data about any deformations in the brain which helps in identifying the right cure. A dye can be injected by the doctor to get a clear picture about the blood being circulated in the brain.
How to Treat Brain Arteriovenous Malformation?
There are many treatment options available for Brain AVM or brain arteriovenous malformation. The primary motive of treatment to brain AVM is to stop hemorrhage. The treatments to control seizures and other neurological difficulties are also considered. The treatments are recommended by the doctor based on the age of the patient, his medical condition and the physical location of an AVM.
Simple medicines may be recommended to treat Brain AVM or brain arteriovenous malformation symptoms such as seizures or headache.
In complex Brain AVM or brain arteriovenous malformation, surgery is recommended. There are three types of surgeries to cure a Brain AVM or brain arteriovenous malformation.
Surgical Removal to Treat Brain AVM Or Brain Arteriovenous Malformation
In case the Brain AVM or brain arteriovenous malformation is bleeding in a region which is approachable, the surgical elimination of AVM is a considered option. The surgeon eliminates the AVM by operating a part of the skull to get an entry inside the brain and operates on the tangled blood vessels.
Intravascular Embolization for Brain AVM or Brain Arteriovenous Malformation
In this surgery, a slim long tube or a catheter is inserted into the blood vessels via an artery in the leg. It is threaded to the blood vessels in the brain by making a use of X-ray imaging technique.
Stereotactic Radiosurgery (SRS) for Brain AVM or brain Arteriovenous Malformation
Stereotactic radiosurgery (SRS) is a non-surgical radiation therapy used to resolve the small tumors of the brain and the functional abnormalities.
Stereotactic radiosurgery (SRS) can deliver highly targeted radiation in smaller high dose treatments, which can help preserve the healthy tissue.
Stereotactic radiosurgery (SRS) treatment is used to scar the damaged blood vessels, which clot over a period of time. It is apt for small AVM’s which cannot be removed using surgical procedures.
- Al-Shahi Salman R, White PM, Counsell CE, et al. Outcome after conservative management or intervention for unruptured brain arteriovenous malformations. JAMA. 2014;311(16):1661-1669. doi:10.1001/jama.2014.3200
- Lawton MT, Rutledge WC, Kim H, Stapf C, Whitehead KJ, Li DY, Krings T, terBrugge K, Kondziolka D, Morgan MK, Moon K, Spetzler RF. Brain arteriovenous malformations. Nat Rev Dis Primers. 2015 May 7;1:15008. doi: 10.1038/nrdp.2015.8. PMID: 27188832.
- Gross BA, Du R. Natural history of cerebral arteriovenous malformations: a meta-analysis. J Neurosurg. 2013;118(2):437-443. doi:10.3171/2012.9.JNS121280
- Kim H, Abla AA, Nelson J, et al. Silent arteriovenous malformation hemorrhage and the recognition of “unruptured” arteriovenous malformation patients who benefit from surgical intervention. Neurosurgery. 2012;71(5):934-943. doi:10.1227/NEU.0b013e31826d98dd
- van Beijnum J, van der Worp HB, Buis DR, Al-Shahi Salman R, Kappelle LJ, Rinkel GJ, Vandertop WP, Algra A, Klijn CJ. Treatment of brain arteriovenous malformations: a systematic review and meta-analysis. JAMA. 2011;306(18):2011-2019. doi:10.1001/jama.2011.1618
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