Cerebral thrombosis is a type of stroke that happens when a blood clot blocks an artery in the brain. The signs usually start without warning and get worse over minutes to hours. Knowing what to look for can help you act fast and limit brain damage. The most common first clue is sudden numbness or weakness on one side of the body—face, arm, or leg. Your smile may droop, or you may not be able to lift one hand. Speech can become slurred or jumbled; some people lose the ability to speak at all. Vision may blur or disappear in... Learn more