What sort of problem is an arteriovenous malformation?

Vascular: I will refer this to experts in the blood vessels. Thanks for asking this important question.

Brain blood vessel: Generally people are born with brain arteriovenous malformations (avm). If found by accident, any kind of treatment should be considered carefully and deliberately. Options include radiosurgery, embolization and resection. If there has been bleeding associated with the avm, some combination of endovascular embolization and surgical removal is necessary. Expert evaluation is highly recommended.

Other places: Another common location is in the colon, which can lead to intermittent rectal bleeding and sometimes requires treatment by cauterization.

Short circuit: An avm is a short circuit between arteries and veins without capillaries in-between. Depending on size, location, flow, and other characteristics, it can be silent or it can cause symptoms. Ultimately, it can bleed and be life threatening.