Monday, July 18, 2011
Medical Mondays: AVM, not ATM, not ATV
aneurysms, and I got several comments wondering if an AVM could also cause serious damage in the brain. And also, what the heck was an AVM?
An AVM is an arteriovenous malformation. Before I explain what an AVM is, first we start with the normal way things go in that body of yours.
Usually blood, rich with oxygen from the lungs, is pumped from your heart and delivered to your body parts via strong, thick-walled vessels. They have to be thick to withstand the pressure needed to push the blood everywhere.
They divide into smaller vessels (eventually to tiny capillaries), drop off their oxygen, pick up the carbon dioxide, and regroup into larger, thin-walled vessels of your veins.
Then back to the right side of the heart, a pump to the lungs to pick up more oxygen, back again now to the left side of the heart, and a huge pump to start it all over again.
An AVM is a malformation where the artery goes directly to a vein and bypasses all the smaller vessels. It can be a tangle of vessels, and can be found in the brain or other organs.
Who gets them? Usually they're congenital, meaning you're born with them. They occur in 0.1% of the population, about 1/10 the number of people with brain aneurysms. People between the age of 10-40 are the ones who usually experience a problem with them.
Why are they bad? Well, they tend to bleed easily. Veins aren't used to withstanding the pressure directly from arteries. Even unruptured, they can cause seizures, headaches, and neurological problems.
How are they treated? By surgery, radiation, or embolization (something is put inside the AVM to block it off).
Now you all know about AVMs. And you can use have your characters suffer from them.