Classification. Hives and angioedema are described by the length of time that symptoms last. A rash and/or swelling lasting less than six weeks is called acute hives/angioedema. Episodes that last more than six weeks are described as chronic hives/angioedema. The causes and the bodyâs reactions that lead to development of hives are different in acute and chronic hives/angioedema, and so treatment is also different.
Types of Stroke. An ischemic stroke occurs if an artery that supplies oxygen-rich blood to the brain becomes blocked. Blood clots often cause the blockages that lead to ischemic strokes. The two types of ischemic stroke are thrombotic (throm-BOT-ik) and embolic (em-BOL-ik). In a thrombotic stroke, a blood clot (thrombus) forms in an artery that supplies blood to the brain. In an embolic stroke, a blood clot or other substance (such as plaque, a fatty material) travels through the bloodstream to an artery in the brain. With both types of ischemic stroke, the blood clot or plaque blocks the flow of oxygen-rich blood to a portion of the brain.
This type of stroke is the most common. A blood clot â a clump of blood that sticks together â is usually to blame for ischemic strokes. They can also happen when arteries become narrow and clogged with plaque. Plaque is a mix of cholesterol and other fatty stuff that sticks to the walls of blood vessels.