Arteriovenous malformation
An arteriovenous malformation (AVM) is a congenital malformation of the blood vessels in which arteries are directly connected to veins without intervening capillaries . AVM are one of the vascular anomalies. In older literature, the AVM is often counted as an angioma , but it is not a tumor-like growth.
anatomy
The vascular malformation consists of a network of direct connections between the blood-supplying arteries and the blood-draining veins, whereby an exact demarcation in the area of the AVM is often no longer possible. The increased blood flow within the AVM causes the blood vessels to widen. Due to the optical structure of the malformation, an AVM is also described as a vascular tangle , AVM directly under the surface of the skin can be visible as a coiled vein network. The center of the apparently knotted blood vessels is known in medicine as a nidus (Latin for "nest") or shunt (English for "short-circuit connection").
Histologically , the structure of the blood vessels in the area of the AVM differs from that of "healthy" blood vessels. Within the AVM, some wall layers of the arteries / veins are extremely thin or completely absent. The blood vessels of the AVM are therefore more prone to rupture , which can lead to (internal) bleeding .
The size of an AVM is variable, the expansion of the AVM can both increase and decrease over time.
Aneurysms can also be present in the area of the arteriovenous malformation .
Demarcation
Like arteriovenous fistulas, arteriovenous malformations are direct connections between arteries and veins. Arteriovenous fistulas , however, are usually not congenital and can result from damage to arteries and veins that are close together or can be artificially created for the treatment of diseases.
localization
Arteriovenous malformations can occur throughout the body and have different symptoms and effects.
- Cerebral AVM in or on the brain can cause a stroke and are therefore the riskiest type.
- Cranial AVM on the skull
- Spinal AVM in the spinal canal and spinal cord can cause paralysis .
- Pulmonary AVM within the lungs can cause cyanosis and abscesses , see also Osler's disease .
- AVM within muscle tissue can cause hypotension and joint pain .
- AVM in the area of the eyes and retina , see Bonnet-Dechaume-Blanc syndrome
- AVM on the extremities
literature
- Peter Berlit (Ed.): Clinical Neurology . 2nd Edition. Springer Medicine, Heidelberg 2006, ISBN 3-540-01982-0 .
- S1 guideline for cerebral vascular malformations of the German Society for Neurology, updated version from 2014, valid until September 2017, PDF version (AWMF register number 030/088, not available online at AWMF at the time of linking)
- ISSVA classification (PDF file; 169 kB) Classification of vascular anomalies. Odile Enjolras, Michel Wassef and Rene Chapot: "Color Atlas of Vascular Tumors and Vascular Malformations", Cambridge University Press, 2007 (excerpt)
Individual evidence
- ↑ a b c Henkes, Berg-Dammer, Kühne: Arteriovenous malformations. In: Peter Berlit (Ed.): Clinical Neurology . 2nd Edition. Springer Medizin, Heidelberg 2006, ISBN 3-540-01982-0 , pp. 1040 ff. → limited preview in the Google book search.
- ^ A b Hassler, Schick: Arteriovenous malformations of the CNS. In: Moskopp, Wassmann (Hrsg.): Neurosurgery, manual for further training and interdisciplinary reference work. Schattauer, Stuttgart 2005, ISBN 3-794-51991-4 , pp. 382-392.
- ↑ a b Christian Helmut Peter Kühn: Radiosurgery for the treatment of cerebral arteriovenous malformations using the computer-controlled micro-multileaf collimator. Dissertation, Medical Faculty, University of Cologne, 2009. PDF version . Retrieved December 13, 2011
