Arteriovenous malformation (AVM) is a congenital vascular condition characterized by an abnormal connection between arteries and veins, bypassing the capillary system. This malformation can disrupt normal blood flow and lead to various complications, depending on its location and size. AVMs can occur in different parts of the body, including the brain, spinal cord, and other organs.

Pathophysiology

In a normal vascular system, blood flows from arteries to capillaries and then to veins. However, in an AVM, the direct connection between arteries and veins causes blood to bypass the capillaries, resulting in high-pressure blood flow through the abnormal vessels. This can lead to weakened blood vessel walls, potential bleeding, and other complications.

Types of AVMs

1. Cerebral AVM: Located in the brain, these AVMs can cause neurological symptoms, such as headaches, seizures, and cognitive impairments. They carry a risk of hemorrhage, which can lead to stroke or other severe complications.
2. Spinal AVM: Found in the spinal cord, these AVMs may result in symptoms such as back pain, weakness, or sensory loss, and can affect motor functions and sensation.
3. Peripheral AVM: Occurring in areas like the limbs or organs, these AVMs can cause swelling, pain, or bleeding in the affected area.

Symptoms

The symptoms of AVMs can vary widely based on their location and size, but common symptoms include:

• Headaches: Particularly in cases of cerebral AVMs, headaches can be severe and persistent.
• Seizures: Resulting from abnormal blood flow and pressure in the brain.
• Neurological Deficits: Such as weakness, numbness, or changes in vision or speech, depending on the AVM’s location.
• Pain or Swelling: In peripheral AVMs, symptoms can include localized pain or noticeable swelling.

Diagnosis

1. Imaging Studies:

   • Magnetic Resonance Imaging (MRI): Provides detailed images of the brain or spinal cord, helping to identify the location and size of the AVM.
   • Computed Tomography (CT) Scan: Useful for detecting bleeding or structural abnormalities associated with AVMs.
   • Digital Subtraction Angiography (DSA): The gold standard for visualizing the blood vessels and the abnormal connections of AVMs, using contrast dye and X-ray imaging.
   • Ultrasound: May be used for peripheral AVMs to assess blood flow and structural details.

2. Clinical Evaluation: A thorough assessment of symptoms and medical history helps in understanding the extent and impact of the AVM.