Arteriovenous Malformation (AVM) Of The Brain


Article Author:
Maria Bokhari


Article Editor:
Syed Rizwan Bokhari


Editors In Chief:
Mohamed Hegazy
Najib Murr


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Steve Bhimji
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Nazia Sadiq
Hajira Basit
Phillip Hynes
Tehmina Warsi


Updated:
2/16/2019 10:32:29 AM

Introduction

Arteriovenous malformations (AVMs) are a developmental anomaly of the vascular system, consisting of tangles of poorly formed blood vessels in which the feeding arteries are directly connected to a venous drainage network without any interposed capillary system.[1][2][3][4]

AVMs can occur anywhere in the body, however, brain AVMs are of special concern because of the inherent high risk of bleeding of the abnormal blood vessels that can cause neurological damage.

Etiology

Not much is known about the etiology of brain AVMs. The cause of brain AVMs is yet unknown, however, it is possibly multifactorial; apparently both genetic mutation and angiogenic stimulation (the physiological process of formation of new blood vessels from pre-existing vessels) playing roles in AVM development. Some believe that AVMs develop in utero. While others advocate an angiopathic reaction, following either a cerebral ischemic or hemorrhagic event (subtypes of stroke) as a primary factor in their development.[5][6][7][8]

Epidemiology

The incidence in the United States is 1.34 per 100,000 person-years, although the actual prevalence rate is higher due to clinically silent disease, as only 12% of AVMs are estimated to become symptomatic. The mortality rate is 10-15% of patients who have hemorrhage, and morbidity varies from approximately 30-50%. There is no sex predilection. Despite the considered congenital origin of AVMs, the clinical presentation most commonly occurs in young adults.

Pathophysiology

Arteriovenous malformations are composed of a central vascular nidus which is a conglomerate of arteries and veins. There is no intervening capillary bed, and the feeding arteries drain directly into the draining veins by one or multiple fistulae. These arteries lack the normal muscularis layer and the draining veins often appear dilated due to the shunted high-velocity arterial blood flow entering through the fistulae. 

AVMs cause neurological dysfunction through the following three possible pathophysiological mechanisms. Firstly, the abnormal blood vessels have a propensity to bleed resulting in hemorrhage occurring in the subarachnoid space, the intraventricular space or, more commonly in the brain parenchyma. Secondly, in the absence of hemorrhage, seizures may occur as a consequence of the mass effect of AVM or venous hypertension in draining veins. The third important cause of slowly progressive neurological deficits is attributed to the"steal phenomenon" which is thought to be related to normal brain parenchyma deprivation from nutrients and oxygen, as blood bypasses the normal capillary bed to the malformed arteriovenous channels. 

History and Physical

AVMs tend to be clinically asymptomatic in 15% if cases until the presenting event occurs. 

  • Approximately 41 to 79 percent present with intracranial hemorrhage. AVMs are the second most common cause of intracranial bleed after cerebral aneurysms, responsible for 10 percent of all cases of subarachnoid hemorrhage. Children are more likely to present with hemorrhage than adults. Hemorrhages are usually intraparenchymal, but can primarily occur in the subarachnoid space. Symptoms due to hemorrhage include loss of consciousness, sudden and severe headache, nausea, vomiting as the coagulated blood makes its way down to be dissolved in the individual's spinal fluid. Reported sequelae caused by local brain tissue damage on the bleed site are also possible, including seizure, hemiparesis, a loss of touch sensation on one side of the body and deficits in language processing. Minor bleeding may be asymptomatic. Following arrest of bleeding, most AVM victims recover symptomatically, as the damaged blood vessel repairs itself.
  • Studies report seizure as a presenting disorder in 15-40% of patients. The risk of seizures increases with cortically-located, large, multiple, and superficial-draining AVMs. Seizures are typically focal, either simple or partial complex, but often show secondary generalization.

  • The progressive neurological deficit may occur in 6-12% of patients over a few months to several years. A vascular steal syndrome has been hypothesized to cause this presentation, but in most cases, this is related to mass effect, hemorrhage, or seizure. These include seizure, hemiparesis, visual disturbances, loss of sensation in one-half of body and aphasia. Minor bleeding can occur with no noticeable symptoms. 

  • A headache – There are no specific headache features that associate with AVM, which may be incidental to the headaches.

Evaluation

Brain AVMs are typically first identified on cross-sectional imaging (CT or MRI). A combination of MRI and angiography are often helpful to plan therapy and predicting the likely success and associated risks of surgical, endovascular, or radiological therapy.

Computed tomography — On non-contrast CT the nidus is blood density and therefore usually somewhat hyperdense compared to adjacent brain, enlarged draining veins and calcification may be evident. Although many of them are large, however, no mass effect or edema is present unless they bleed. On postcontrast CT especially with CT angiogram, the diagnosis is easily derived with visible feeding arteries, nidus and draining veins apparent in the so-called "bag of worm" appearance. The exact anatomy of feeding vessels and draining veins can usually be delineated with angiography. The sensitivity of CT to identify brain AVMs in the acute setting of hemorrhage is reduced owing to compression of the nidus by the hematoma so more sensitive techniques such as MRI or angiography are required.

Magnetic resonance imaging — MRI is very sensitive for plotting the location of the brain AVM nidus and often an associated draining vein or any distant bleeding event. Fast flow in a conglomerate of tangled blood vessels generates serpiginous and tubular flow voids seen on bothT1 and T2, however mostly evident on T2 weighted images. Complications like the previous hemorrhage, adjacent brain edema and atrophy may be seen.

After radiosurgery, MRI can evaluate the regression of the nidus volume, post therapy edema as well as the radiation necrosis in the radiation field.

Angiography — It remains the gold standard for the diagnosis and treatment planning. Nidus configuration, its relationship, and drainage to surrounding vessels are precisely evaluated. The presence of associated aneurysm suggests a higher risk for hemorrhage. Contrast transit time, which relates to the flow state of the lesion, can provide the critical information for the endovascular treatment planning.

Treatment / Management

Treatment modalities —Invasive management is recommended for younger patients with presence of one or more of the high-risk features for an AVM rupture, whereas in the case of older individuals with no high-risk features, the usual best treatment is medical management. In these particular patients, anticonvulsants for seizure control and pertinent analgesia for headaches may be the only management required. Several studies report that a history of the previous rupture is one of the most significant risk factors that predict the long-term bleeding risk. Others important factors include patient age, AVM location, the presence of aneurysms, size, and other vascular features. Patients with AVMs and intractable epilepsy are also candidates for AVM treatment. [9][10][11][12][13]

Surgical excision — Open microsurgical excision is the mainstay of treatment and offers the cure for patients considered to be at high risk of hemorrhage.

Spetzler-Martin Grade (SMG) scale is commonly employed for assessment of the risk of surgical morbidity and mortality with brain AVMs. It is a composite score of nidus size (<3 cm, 3-6 cm, >6 cm; 1-3 points), eloquence of adjacent brain (1 point  for lesions located in brainstem, cerebellar peduncles, thalamus, hypothalamus, or language, sensorimotor, or primary visual cortex), and venous drainage (1 point if any or all of venous drainage is via deep veins, such as basal veins, internal cerebral veins, or precentral cerebellar veins). The higher the score, the higher the associated surgical morbidity and mortality risk.

Radiotherapy and endovascular embolization are not only useful alternatives to the surgical treatment in patients at high risk for surgical therapy but can also be useful adjuncts to the main surgical management.

Enhancing Healthcare Team Outcomes

The diagnosis and management of brain AVM is with a multidisciplinary team that consists of a neurologist, an internist, neurosurgeon and invasive radiologist. The follow up of these patients is usually by the nurse practitioner and primary care provider. The management of brain AVMs depends on the size, location, patient age and status of the AVM (high risk of rupture). While surgery is the mainstay treatment, embolization is another option. The outcomes of these patients depend on the AVM size, presence of symptoms, location, patient comorbidity and mental status. Complications following surgery are common and recovery in many patients is prolonged requiring extensive rehab.The most signficiant risk factor for death is rupture of the AVM.[2][9][14] (Level V)

 


  • Image 5369 Not availableImage 5369 Not available
    Contributed by Jinnah Hospital; Lahore, Pakistan
Attributed To: Contributed by Jinnah Hospital; Lahore, Pakistan

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Arteriovenous Malformation (AVM) Of The Brain - Questions

Take a quiz of the questions on this article.

Take Quiz
Which of the following statements about cerebral arteriovenous malformation hemorrhages is incorrect?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is true about arteriovenous malformations (AVMs)?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
You see an enlarged tentorial branch of the meningohypophyseal trunk. You think to look carefully for:



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which classification system is commonly used for grading of brain arteriovenous malformations (AVMs)?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Arteriovenous Malformation (AVM) Of The Brain - References

References

Claro E,Dias A,Girithari G,Massano A,Duarte MA, Non-traumatic Hematomyelia: A Rare Finding in Clinical Practice. European journal of case reports in internal medicine. 2018;     [PubMed]
Wu EM,El Ahmadieh TY,McDougall CM,Aoun SG,Mehta N,Neeley OJ,Plitt A,Ban VS,Sillero R,White JA,Batjer HH,Welch BG, Embolization of brain arteriovenous malformations with intent to cure: a systematic review. Journal of neurosurgery. 2019 Feb 1;     [PubMed]
Xu H,Wang L,Guan S,Li D,Quan T, Embolization of brain arteriovenous malformations with the diluted Onyx technique: initial experience. Neuroradiology. 2019 Feb 2;     [PubMed]
Heit JJ,Thakur NH,Iv M,Fischbein NJ,Wintermark M,Dodd RL,Steinberg GK,Chang SD,Kapadia KB,Zaharchuk G, Arterial-spin labeling MRI identifies residual cerebral arteriovenous malformation following stereotactic radiosurgery treatment. Journal of neuroradiology. Journal de neuroradiologie. 2019 Jan 15;     [PubMed]
Li W,Sun Q,Duan X,Yi F,Zhou Y,Hu Y,Yao L,Xu H,Zhou L, [Etiologies and risk factors for young people with intracerebral hemorrhage]. Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences. 2018 Nov 28;     [PubMed]
Caranfa JT,Baldwin MT,Rutter CE,Bulsara KR, Synchronous cerebral arteriovenous malformation and lung adenocarcinoma carcinoma brain metastases: A case study and literature review. Neuro-Chirurgie. 2019 Jan 9;     [PubMed]
Khandelwal A,Chaturvedi A,Singh GP,Mishra RK, Intractable brain swelling during cerebral arteriovenous malformation surgery due to contralateral acute subdural haematoma. Indian journal of anaesthesia. 2018 Dec;     [PubMed]
Hofman M,Jamróz T,Kołodziej I,Jaskólski J,Ignatowicz A,Jakutowicz I,Przybyłko N,Kocur D,Baron J, Cerebral arteriovenous malformations - usability of Spetzler-Martin and Spetzler-Ponce scales in qualification to endovascular embolisation and neurosurgical procedure. Polish journal of radiology. 2018;     [PubMed]
Kocer N,Kandemirli SG,Dashti R,Kizilkilic O,Hanimoglu H,Sanus GZ,Tunali Y,Tureci E,Islak C,Kaynar MY, Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection. Neuroradiology. 2019 Feb;     [PubMed]
Ironside N,Chen CJ,Ding D,Ilyas A,Kumar JS,Buell TJ,Taylor D,Lee CC,Sheehan JP, Seizure Outcomes After Radiosurgery for Cerebral Arteriovenous Malformations: An Updated Systematic Review and Meta-Analysis. World neurosurgery. 2018 Dec;     [PubMed]
Mosimann PJ,Chapot R, Contemporary endovascular techniques for the curative treatment of cerebral arteriovenous malformations and review of neurointerventional outcomes. Journal of neurosurgical sciences. 2018 Aug;     [PubMed]
Shovlin CL,Condliffe R,Donaldson JW,Kiely DG,Wort SJ, British Thoracic Society Clinical Statement on Pulmonary Arteriovenous Malformations. Thorax. 2017 Dec;     [PubMed]
Cenzato M,Boccardi E,Beghi E,Vajkoczy P,Szikora I,Motti E,Regli L,Raabe A,Eliava S,Gruber A,Meling TR,Niemela M,Pasqualin A,Golanov A,Karlsson B,Kemeny A,Liscak R,Lippitz B,Radatz M,La Camera A,Chapot R,Islak C,Spelle L,Debernardi A,Agostoni E,Revay M,Morgan MK, European consensus conference on unruptured brain AVMs treatment (Supported by EANS, ESMINT, EGKS, and SINCH). Acta neurochirurgica. 2017 Jun;     [PubMed]
van Essen MJ,Han KS,Lo RTH,Woerdeman P,van der Zwan A,van Doormaal TPC, Functional and educational outcomes after treatment for intracranial arteriovenous malformations in children. Acta neurochirurgica. 2018 Nov;     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Neurology-Epilepsy. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Neurology-Epilepsy, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Neurology-Epilepsy, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Neurology-Epilepsy. When it is time for the Neurology-Epilepsy board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Neurology-Epilepsy.