Arteriovenous malformation is an abnormal connection between arteries and veins, bypassing the capillary system.
It wasn’t until I blogged about Surviving Stroke that I knew how serious today’s topic is, infact there’s this Instagram account of someone I know from distance that is apparently a survivor and full of energy.
With my whole yen yen chitchat about interest in a particular field in medicine, I just didn’t know much about ArterioVenous Malformation and I will try and explain-blog about this so that both non medical, health folks and everyone can know about this.
This is an awareness blog post on arteriovenous malformation, trying to spread word out there that this exists and it’s deep.
According to Mayo clinic (which is one hospital I hope to bag my residency or fellowship training from someday, just incase someone knows how I can get in) arteriovenous malformation (AVM) is an abnormal tangle of blood vessels connecting arteries and veins, which disrupts normal blood flow and oxygen circulation.
In a normal situation arteries carry blood containing oxygen from the heart to the brain and in turn the veins carry blood with less oxygen away from the brain back to the heart but in an arteriovenous malformation (AVM) situation, a tangle of blood vessels in the brain bypasses normal brain tissue and directly diverts blood from the arteries to the veins.
Arteriovenous Malformation can occur anywhere but for Surviving Stroke blog guest, hers was in her brain which I think would be extremely serious and pretty dangerous hence why she went in for surgery and the rest you can read up from the post just incase you missed it.
Now we can ask how common is Brain Arteriovenous Malformation?
To answer that I will quote American Stroke Association that said Brain Arterio Venous Malformation occur in less than 1 percent of the general population, seen more among males than in females.
Brain Arterio venous malformation are congenital which simply means individuals are born with, they are neither hereditary nor passed down to generations.
Signs and Symptoms of Arteriovenous Malformation
Arterio venous malformation signs and symptoms depends on where the malformation occured.
For cerebral AVM, it’s more of headaches, epileptic seizures and
- Bleeding (45% of cases)
- Acute onset of severe headache which can be described as the worst headache of the patient’s life. Depending on the location of bleeding, may be associated with new fixed neurologic deficit. In unruptured brain AVMs, the risk of spontaneous bleeding may be as low as 1% per year however after the first rupture, the annual bleeding risk may increase to more than 5%. Individuals between 11 to 35 years old and who have an AVM are at a slightly higher risk of bleeding. The risk of death related to each bleed is 10 to 15%. The chance of permanent brain damage is 20 to 30%. Each time blood leaks into the brain, normal brain tissue is damaged. This results in loss of normal function, which may be temporary or permanent.
- Seizure or brain seizure (46%) depending on the location of the AVM, it can cause loss of vision in one place.
- Headache (34% of cases)
- Progressive neurologic deficit (21%)
- May be caused by mass effect or venous dilatations. Presence and nature of the deficit depend on location of lesion and the draining veins.
Other symptoms of Arteriovenous Malformation that can be experienced include
- Difficulties with movement coordination, including muscle weakness and even paralysis;
- Vertigo (dizziness).
- Loss of coordination (ataxia) that can cause problems with gait.
- Difficulties of speech (dysarthria) and communication, such as aphasia.
- Difficulties with everyday activities, such as apraxia;
- Abnormal sensations (numbness, tingling, or spontaneous pain);
- Memory and thought-related problems, such as confusion, dementia or hallucinations.
- Weakness in the lower extremities
- Back pain
- Vision problems, including losing part of your field of vision, loss of control of eye movements, or swelling of part of the optic nerve.
- Pediatric patients
- Congestive Heart failure
- Prominent scalp veins
- Learning and trouble behaviour
- A buildup of fluid in the brain (hydrocephalus) that causes enlargement of the head
- Swollen veins on the scalp
- Failure to thrive.
How Is it diagnosed?
Like in my health posts, it’s pretty similar where the doctor reviews presenting symptoms and conducts physical Examination but other tests are:
- Cerebral angiography. Also called arteriography, this test uses a special dye called a contrast agent injected into an artery. The dye highlights the structure of blood vessels to better show them on X-rays.
- Computerized tomography (CT). CT scans use X-rays to create images of the head, brain or spinal cord and can help show bleeding.
- Magnetic resonance imaging (MRI). An MRI uses powerful magnets and radio waves to show detailed images of the tissues. An MRI can pick up on small changes in these tissues.
- Magnetic resonance angiography (MRA). An MRA captures the pattern and the speed and distance of blood flow through the vascular abnormalities.
- Transcranial Doppler ultrasound. This type of ultrasound uses high-frequency sound waves to create an image of the blood flow to help diagnose large and medium AVMs, as well as bleeding.
Arteriovenous Malformation treatment depends on the area where the abnormality is found and if the abnormality is in an area where it can be surgically treated for surgery is the main form of treatment.
AVM-specific treatment may also involve endovascular embolization, neurosurgery or radiosurgery. Embolization, which is cutting off the blood supply to the AVM with coils, particles, acrylates, or polymers introduced by a radiographically guided catheter, may be used in addition to neurosurgery or radiosurgery, but is rarely successful in isolation except in smaller AVMs.
Gamma knife may also be used.
Treatment of lung AVMs is performed with endovascular embolization alone, which is considered the standard of care.
Stereotactic radiosurgery. An AVM which is not too large but in an area that’s difficult to reach by regular surgery may be treated with stereotactic radiosurgery. In this procedure, a cerebral angiogram is done to localize the AVM. Focused-beam high energy sources are then concentrated on the AVM to cause a scar and allow the AVM to “clot off.”
Interventional neuroradiology/endovascular neurosurgery. It may be possible to treat part or all of the AVM by placing a catheter (small tube) inside the blood vessels and blocking off the abnormal vessels with various materials, like glue or coils.
Before surgery, it can be managed symptomatically where the seizures, headaches and back pain are prescribed medications.
After Treatment measures, patients are followed up by neurologist for any seizures, headaches, or focal neurologic deficits.
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