Arteriovenous malformation

Infobox_Disease
Name = Arteriovenous malformation


Caption =
DiseasesDB = 15235
ICD10 = ICD10|Q|27|3|q|20, ICD10|Q|28|0|q|20, ICD10|Q|28|2|q|20
ICD9 = ICD9|747.6, ICD9|747.81
ICDO =
OMIM =
MedlinePlus = 000779
eMedicineSubj = search
eMedicineTopic = Arteriovenous%20Malformation
MeshID = D001165

Arteriovenous malformation or AVM in the majority of cases is a congenital disorder consisting of a connection between veins and arteries, this pathology is universally known because of its occurrence in the central nervous system, but can appear in any location.

The genetic transmission patterns of AVM -if any- are unknown, and AVM is not generally thought to be an inherited disorder, unless in the context of a specific hereditary syndrome.

Signs and symptoms

Symptoms of AVM vary according to the location of the malformation. Roughly (88% -needs citation) 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), rarely its expansion or a micro-bleed from it, could cause epilepsy, deficit or elicit pain.

The most general symptoms include headache and epilepsy, with more specific symptoms occurring that normally depend on the location of the malformation and the individual. Other possible symptoms include:NINDS|avms|Arteriovenous Malformation Information Page]

* Difficulties with movement or coordination, including muscle weakness and even paralysis;
* vertigo (dizziness);
* Difficulties of speech (dysarthria) and communication, such as alogia;
* 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.

Pathophysiology

Arteries and veins are part of the human cardiovascular system. Normally, the arteries in the vascular system carry oxygen-rich blood. Structurally, arteries divide and sub-divide repeatedly, eventually forming a sponge-like capillary bed. Blood moves through the capillaries, giving up oxygen and taking up waste products from the surrounding cells (CO2). Capillaries successively join together, one upon the other, to form veins that carry blood away. The heart acts to pump blood through arteries and uptake the venous blood.

If the capillary bed is thought of as a sponge, then an AVM is the rough equivalent of jamming a tangle of flexible soda straws from artery to vein through that sponge. On arteriogram films AVM formation often resemble a tangle of spaghetti noodles. This tangle of blood vessels forms a relatively direct connection between high pressure arteries and low pressure veins.

The result is a collection of blood vessels with abnormal connections and no capillaries. This collection, often called a "nidus", can be extremely fragile and prone to bleeding.

Diagnosis

AVMs can occur in various parts of the body

* brain, causing a cerebral arteriovenous malformation
* spleencite journal |author=Agrawal A, Whitehouse R, Johnson RW, Augustine T |title=Giant splenic artery aneurysm associated with arteriovenous malformation |journal=J. Vasc. Surg. |volume=44 |issue=6 |pages=1345–9 |year=2006 |month=December |pmid=17145440 |doi=10.1016/j.jvs.2006.06.049 |url=http://linkinghub.elsevier.com/retrieve/pii/S0741-5214(06)01369-3 |accessdate=2008-06-01]
* lungcite journal |author=Chowdhury UK, Kothari SS, Bishnoi AK, Gupta R, Mittal CM, Reddy S |title=Successful Lobectomy for Pulmonary Arteriovenous Malformation Causing Recurrent Massive Haemoptysis |journal=Heart Lung Circ |volume= |issue= |pages= |year=2008 |month=February |pmid=18294908 |doi=10.1016/j.hlc.2007.11.142 |url=http://linkinghub.elsevier.com/retrieve/pii/S1443-9506(07)01113-4 |accessdate=2008-06-01]
* kidneycite journal |author=Barley FL, Kessel D, Nicholson T, Robertson I |title=Selective embolization of large symptomatic iatrogenic renal transplant arteriovenous fistula |journal=Cardiovasc Intervent Radiol |volume=29 |issue=6 |pages=1084–7 |year=2006 |pmid=16794894 |doi=10.1007/s00270-005-0265-z]
* spinal cordcite journal |author=Kishi K, Shirai S, Sonomura T, Sato M |title=Selective conformal radiotherapy for arteriovenous malformation involving the spinal cord |journal=Br J Radiol |volume=78 |issue=927 |pages=252–4 |year=2005 |month=March |pmid=15730991 |doi= |url=http://bjr.birjournals.org/cgi/pmidlookup?view=long&pmid=15730991]
* livercite journal |author=Bauer T, Britton P, Lomas D, Wight DG, Friend PJ, Alexander GJ |title=Liver transplantation for hepatic arteriovenous malformation in hereditary haemorrhagic telangiectasia |journal=J. Hepatol. |volume=22 |issue=5 |pages=586–90 |year=1995 |month=May |pmid=7650340 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/0168-8278(95)80455-2 |accessdate=2008-06-01]
* intercostal spacecite journal |author=Rivera PP, Kole MK, Pelz DM, Gulka IB, McKenzie FN, Lownie SP |title=Congenital intercostal arteriovenous malformation |journal=AJR Am J Roentgenol |volume=187 |issue=5 |pages=W503–6 |year=2006 |month=November |pmid=17056881 |doi=10.2214/AJR.05.0367 |url=http://www.ajronline.org/cgi/pmidlookup?view=long&pmid=17056881]
* iriscite journal |author=Shields JA, Streicher TF, Spirkova JH, Stubna M, Shields CL |title=Arteriovenous malformation of the iris in 14 cases |journal=Arch. Ophthalmol. |volume=124 |issue=3 |pages=370–5 |year=2006 |month=March |pmid=16534057 |doi=10.1001/archopht.124.3.370 |url=http://archopht.ama-assn.org/cgi/pmidlookup?view=long&pmid=16534057]
* spermatic cordcite journal |author=Sountoulides P, Bantis A, Asouhidou I, Aggelonidou H |title=Arteriovenous malformation of the spermatic cord as the cause of acute scrotal pain: a case report |journal=J Med Case Reports |volume=1 |issue= |pages=110 |year=2007 |pmid=17939869 |doi=10.1186/1752-1947-1-110 |url=http://www.jmedicalcasereports.com/content/1//110]

AVMs may occur in isolation or as a part of another disease (e.g. Von Hippel-Lindau disease or hereditary hemorrhagic telangiectasia).

This bleeding can be devastating, particularly in the brain. It can cause severe and often fatal strokes. If detected before a stroke occurs, usually the arteries feeding blood into the nidus can be closed off, ensuring the safety of the patient.

Treatment

Treatment can be symptomatic, or it can involve surgery or radiation therapy.

Epidemiology

An estimated 300,000 Americans have AVMs, of which 12% (approximately 36,000) will exhibit symptoms that differ greatly in severity.

Society and culture

*On December 13, 2006, Senator Tim Johnson was diagnosed with AVM and treated at George Washington University Hospital. [ [http://www.msnbc.msn.com/id/16199440/ "Sen. Johnson recovering after brain surgery"] , AP, December 14, 2006.]

Cases in fiction

*The plot of William Finn's 1998 Off-Broadway musical, "A New Brain", revolves around the main character's battle with AVM.
*The character Nate Fisher on the HBO television show "Six Feet Under" suffers from AVM.
*Patients with AVM appeared in two episodes of the series "House", DNR, fictional British medical show Harley Street.

Research directions

Despite many years of research, the central question of whether to treat AVMs has not been answered. All treatments, whether involving surgery or drugs, have risks and side-effects. Therefore it might be better in some cases to avoid treatment altogether and simply accept a small risk of coming to harm from the AVM itself. This question is currently being addressed in clinical trials [ [http://www.cliniclog.com/arterio-venous_malformations.php Research trials in arterio-venous malformations; Rustam Al-Shahi Salman] ] .

References

External links

* [http://www.dmoz.org/Health/Conditions_and_Diseases/Neurological_Disorders/Stroke/Support_Groups/Chats_and_Forums/ AVM Support Groups] from the DMOZ Open Directory.
* [http://avm.ucsf.edu University of California San Francisco AVM research.]