A stroke is the result of brain damage arising either from a blood clot in the brain, which blocks the blood vessel concerned, depriving that part of the brain of oxygenated blood so that the cells there die; or from a burst blood vessel in the brain, which again causes brain cells to die in that area because the blood that leaks out compresses the area and clots, preventing oxygenated blood getting through. Someone who has had a stroke may be paralyzed down one side, may have different sized pupils and may be unable to speak properly, although he or she may try. The casualty may be confused and anxious, and might collapse and become unconscious. Follow the general rules for dealing with unconsciousness in any suspected case of stroke, and arrange for the person’s immediate transfer to hospital. The older a casualty is, the higher the chances that he or she has suffered a stroke.