Arteriovenous malformations

Arteriovenous malformations (AVM) are congenital non-hereditary anomalies in the development of the vascular system of the brain and are balls of various shapes and sizes formed as a result of the disordered interweaving of pathological vessels. In arteriovenous malformations, most often, there is no capillary network, as a result of which direct shunting of blood from the arterial pool to the system of superficial and deep veins occurs. This leads to the formation of 2 blood flow systems - through normal vessels of the brain and the vascular network of the malformation, while the blood supply to normal brain tissue decreases, which leads to an increase in ischemic and degenerative phenomena in the brain. Over time, aneurysms are formed from AVMs. AVM most often manifests itself in the brain, but it can also occur in the spinal cord. AVM begins to develop during the intrauterine stage. With age, it grows unpredictably. 

Symptoms:

  • Intracranial hemorrhage; this is the most common symptom
  • Seizures- occurs in 20%-25% of all cases
  • Headache. Headaches are a common symptom, occurring in approximately 15% of cases
  • Muscle weakness
  • Paralysis (loss of movement) of a body part
  • Dizziness
  • Inability to perform purposeful movements - apraxia
  • Loss of coordination, especially when walking - ataxia
  • Abnormal blood flow sound. This sound, also called a bruit, can be detected with a stethoscope. It is caused by extremely rapid blood flow through the arteries and veins in an arteriovenous malformation
  • Sudden, severe back pain
  • Difficulty speaking or understanding speech
  • Loss of sensation (hearing, taste, touch)
  • Vision problems
  • Memory loss
  • Difficulty thinking or confusion
  • Hallucinations
  • Dementia.

Arteriovenous malformations can cause serious damage to the brain and spinal cord by:

  • Decreasing the amount of oxygen reaching the brain
  • Bleeding (hemorrhage) occurs in tissues that make up the nervous system, including the brain and spinal cord)
  • Compression or displacement of part of the brain or spinal cord

Complications:

Hemorrhage into the brain occurs when the wall of a dilated vessel ruptures or when an AVM aneurysm bursts. Such bleeding is life-threatening. A quarter of all patients affected by any type of hemorrhage die; one in three becomes disabled. The risk of microbleeding each year from an AVM is about 4%. However, some AVMs never bleed. The highest risk of bleeding is in patients aged 40 to 55 years.