Arteriovenous Malformations

What are arteriovenous malformations (AVMs)?

From: MedlinePlus, National Library of Medicine

Arteriovenous malformations (AVMs) are defects in your vascular system. Your vascular system is your body's network of blood vessels. It includes your:

• Arteries, which carry oxygen-rich blood from your heart to your tissues and organs.
• Veins, which carry the blood and waste products back to your heart.
• Capillaries, which are tiny blood vessels that connect your small arteries to your small veins.

An AVM is an abnormal tangle of arteries and veins. They are connected to each other, with no capillaries between them. Without the capillaries, the blood flow from the arteries goes directly into the veins at a faster rate than normal. Because of this, the nearby tissue does not get all the oxygen it would normally get. This lack of oxygen can lead to tissue damage and the death of nerve cells and other cells. The fast rate of blood flow can also increase the blood pressure inside the arteries and veins. This can weaken the arteries and veins. A weakened artery or blood vessel could burst or leak blood.

What causes arteriovenous malformations (AVMs)?

From: MedlinePlus, National Library of Medicine

AVMs are rare. The cause of AVMs is unknown. Most of the time, people are born with them. But sometimes they can appear shortly after birth or later in life.

What are the symptoms of arteriovenous malformations (AVMs)?

From: MedlinePlus, National Library of Medicine

The symptoms of AVM will depend on where the AVM is located. They can happen anywhere in the body, but they are more common in the brain or spinal cord. Most people with brain or spinal cord AVMs have few, if any, major symptoms. But if a weakened blood vessel bursts, it can spill blood into the brain (called a hemorrhage). Severe hemorrhages can cause a stroke and brain damage.

If an AVM is causing symptoms, they can include:

• Seizures
• Headache
• Pain in the area where the AVM is located
• Vision problems
• Muscle weakness
• Problems with movement and speech
• Confusion
• Dizziness
• Loss of consciousness

How are arteriovenous malformations (AVMs) diagnosed?

From: MedlinePlus, National Library of Medicine

To find out if you have an AVM, your health care provider:

• Will ask about your symptoms and medical history.
• Will do a physical exam. This may include listening for a bruit. A bruit is whooshing sound caused by the rapid blood flow through the arteries and veins of an AVM.
• May order imaging tests, such as a CT scan, MRI, ultrasound, or cerebral angiography. For a cerebral angiography, you are injected with a special dye that helps the blood vessels in your brain show up on x-rays.

What are the treatments for arteriovenous malformations (AVMs)?

From: MedlinePlus, National Library of Medicine

Treatments for AVMs will depend on factors such as:

The treatment options may include:

• Where the AVM is located
• Its size
• Your symptoms
• Your overall health
• Your risk of bleeding
• Monitoring for any signs that may mean you have an increased risk of hemorrhage.
• Medicines to help with the symptoms from AVMs.
• Surgery, which may be done if you have a higher-than-usual risk of bleeding. There are a few different types of surgery for AVMs. In some cases, you may have more than one type. Surgery can be risky, especially when it's done on the brain or spinal cord. So you and your provider will need to discuss the risks and benefits of doing the surgery before you make a decision.

Which doctor should you see?

The suggested department for discussing Arteriovenous Malformations is Haematology, with a haematologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which blood-cell, marrow, bleeding or clotting finding matters most?
• Does the diagnosis need confirmation or a more precise subtype?
• Which symptoms or laboratory changes should trigger earlier review?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.