Clinical shock should not be confused with a shock meaning someone’s emotional reaction to bad news or sudden excitement. Clinical shock is the body’s reaction to a significant loss in overall blood volume or the diversion of the blood supply away from the major organs, for example in the event of major burns, extreme bleeding or a heart attack. Loss of fluids from the body through severe diarrhoea or vomiting may also result in shock. As blood pressure falls, supplies of blood to vital organs (such as the brain) may fail. If the blood supply to the brain diminishes, its control of the heartbeat and blood-vessel tone weakens and the body enters a vicious spiral in which the blood circulation becomes increasingly sluggish. The casualty in shock feels cold and looks pale. The pulse is weak but fast, breathing is rapid and shallow, and the person may complain of dizziness, nausea and thirst. Assuming you have already checked for, and dealt with, any other injuries or problems, first aid treatment for shock is as follows: advise the casualty to lie down and raise his or her feet and legs to encourage blood flow to the major organs. Loosen clothing at the neck and waist and keep the casualty warm by covering him or her with one blanket; do not use a hot water bottle, because this may burn the poorly perfused skin. Do not give the casualty anything to drink, but if he or she complains of being thirsty, moisten the lips with some water. Seek medical help as soon as possible.