Summary about Disease
An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels connecting arteries and veins, disrupting normal blood flow and oxygen circulation. Arteries carry oxygen-rich blood from the heart to the brain and other organs. Veins carry oxygen-depleted blood back to the heart and lungs. When an AVM disrupts this critical process, tissues may not get enough oxygen. AVMs can occur in the brain, spine, or other parts of the body. Brain AVMs are of greatest concern due to potential neurological damage.
Symptoms
AVMs may not cause any signs or symptoms until they rupture (bleed). However, some people may experience:
Seizures: The most common symptom.
Headaches: Can vary in intensity and location.
Muscle weakness or numbness: Often on one side of the body.
Vision problems: Including decreased vision, double vision, or loss of vision.
Difficulty with speech: Slurred speech or trouble finding words.
Unsteadiness: Problems with balance and coordination.
Pulsating sensation in the head: A whooshing or buzzing sound (bruit). If an AVM bleeds (hemorrhage), symptoms are sudden and severe and may include:
Sudden, severe headache
Vomiting
Stiff neck
Loss of consciousness
Seizures
Causes
The exact cause of AVMs is unknown, but they are generally believed to be congenital, meaning people are born with them. They are not inherited. Research suggests AVMs arise from errors during fetal development.
Medicine Used
Medications are primarily used to manage symptoms associated with AVMs, rather than to treat the AVM itself. These may include:
Anti-seizure medications (Anticonvulsants): To prevent or control seizures. Examples include phenytoin, carbamazepine, levetiracetam.
Pain relievers: For headaches.
Medications to lower blood pressure: To reduce the risk of bleeding, if hypertension is present. Medications are not used to directly cure or eliminate the AVM. The primary treatments for AVMs involve surgery, endovascular embolization, or stereotactic radiosurgery.
Is Communicable
No, arteriovenous malformations are not communicable. They are not caused by infection and cannot be transmitted from person to person.
Precautions
There are no specific precautions to prevent the development of an AVM since they are thought to be congenital. However, for individuals *diagnosed* with an AVM, the following precautions are important:
Follow medical advice: Adhere strictly to the treatment plan recommended by your medical team (neurologist, neurosurgeon, interventional radiologist).
Manage blood pressure: Maintain healthy blood pressure, as high blood pressure can increase the risk of bleeding.
Avoid blood thinners: Unless specifically prescribed by your doctor, avoid medications or supplements that thin the blood (e.g., high doses of aspirin, warfarin) as these could increase the risk of hemorrhage.
Limit strenuous activity: Depending on the location and size of the AVM, your doctor may recommend avoiding activities that could increase blood pressure or cause head trauma.
Regular monitoring: Attend all scheduled follow-up appointments for monitoring of the AVM.
Be aware of symptoms: Know the signs and symptoms of AVM bleeding (sudden, severe headache, vomiting, stiff neck, loss of consciousness) and seek immediate medical attention if they occur.
How long does an outbreak last?
AVMs are not an "outbreak" type of illness. They are structural abnormalities. If an AVM bleeds (hemorrhages), the acute event lasts until the bleeding stops and the damage from the hemorrhage stabilizes. This can take days or weeks, requiring intensive medical care. The effects of a bleed, such as neurological deficits, may be permanent, though rehabilitation can help improve function.
How is it diagnosed?
AVMs are typically diagnosed using imaging techniques:
Magnetic Resonance Imaging (MRI): Provides detailed images of the brain and spinal cord to visualize the AVM.
Computed Tomography Angiography (CTA): Uses X-rays and contrast dye to visualize blood vessels.
Cerebral Angiography (Arteriography): The "gold standard" for diagnosing AVMs. A catheter is inserted into an artery (usually in the groin) and guided to the brain. Contrast dye is injected to visualize the AVM and its feeding arteries and draining veins. This provides detailed information about the AVM's size, location, and blood flow dynamics.
CT Scan: May be used initially if bleeding is suspected.
Timeline of Symptoms
The timeline of symptoms can vary greatly:
Asymptomatic AVM: Many people with AVMs have no symptoms until a bleed occurs.
Gradual onset: Some individuals may experience progressive symptoms over time, such as headaches, seizures, or neurological deficits. These symptoms may worsen gradually or occur intermittently.
Sudden onset: AVM rupture (hemorrhage) causes sudden and severe symptoms, such as a severe headache, loss of consciousness, seizures, and neurological deficits. This requires immediate medical attention. There is no set timeline for the appearance or progression of symptoms. The natural history of an AVM is highly variable.
Important Considerations
Risk of Bleeding: The primary risk associated with AVMs is bleeding (hemorrhage). The annual risk of bleeding varies depending on the size, location, and drainage pattern of the AVM, as well as other factors.
Treatment Options: Treatment options for AVMs include surgery, endovascular embolization, and stereotactic radiosurgery. The best treatment approach depends on the individual's specific circumstances.
Multidisciplinary Approach: Management of AVMs requires a multidisciplinary team, including neurologists, neurosurgeons, interventional radiologists, and rehabilitation specialists.
Pregnancy: Pregnancy can increase the risk of AVM rupture due to hormonal and hemodynamic changes. Women with AVMs should discuss the risks and management options with their doctors before and during pregnancy.
Long-Term Monitoring: Even after treatment, long-term monitoring is essential to ensure the AVM is completely eradicated and to monitor for any recurrence.