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Nervous system ORGAN SYSTEMS

Arteriovenous malformation (AVM)

Introduction

Arteriovenous malformation (AVM) is an abnormal connection between arteries and veins, bypassing the capillary system.

  • Sites:
    • Common: Brain (Cerebral AVM), spinal cord, lungs
    • Others: Spleen, kidney, liver, intercostal space, iris, spermatic cord, extremities (arm, shoulder, etc)

Aetiology

Mostly congenital, but not hereditary

Associated with:

  • Osler-Weber-Redu disease
    • Autosomal dominant disease involving blood vessels

Pathophysiology

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In an arteriovenous malformation (AVM), blood passes quickly from the artery to vein, disrupting the normal blood flow and depriving the surrounding tissues of oxygen. | Brain AVM (arteriovenous malformation) – Symptoms and causes. (2018). Mayo Clinic. Retrieved 16 July 2018, from https://www.mayoclinic.org/diseases-conditions/brain-avm/symptoms-causes/syc-20350260
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In a brain AVM, blood passes directly from your arteries to your veins via abnormal vessels. This disrupts the normal process of how blood circulates through your brain. | Brain AVM (arteriovenous malformation) – Symptoms and causes. (2018). Mayo Clinic. Retrieved 16 July 2018, from https://www.mayoclinic.org/diseases-conditions/brain-avm/symptoms-causes/syc-20350260

Histopathology (autopsy)

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Micrograph of an arteriovenous malformation in the brain. HPS stain. | Nephron – CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=12029293

Clinical features

  • Seizures
  • Headache or pain in one area of the head
  • Muscle weakness or numbness in one part of the body

Severe cases:

  • Severe headache
  • Weakness, numbness or paralysis
  • Vision loss
  • Difficulty speaking
  • Confusion or inability to understand others
  • Severe unsteadiness

Case study:


Complications

  • Intracerebral haemorrhage
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A brain AVM may cause bleeding in the brain (hemorrhage), which can damage the surrounding brain tissue, as shown by this CT scan (left) and illustration (right) of an intracerebral hemorrhage. |

Diagnosis

Imaging

 

  • CT/MRI angiography (GOLD STANDARD)
  • MRI/CT
  • Flow-dependent or other contrast-free magnetic resonance imaging techniques
    • Determine the location and other properties of the vasculature

Management

Medical management

Radiosurgical management

Endovascular embolization

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