Shock is a critical condition caused by a sudden drop in blood flow through the body, which can result from trauma, blood loss, infection, burns or other causes. The signs of shock include pale or clammy skin, rapid breathing and heart rate, dizziness, and low blood pressure. First aid for shock involves calling for emergency help, keeping the person lying down, controlling any bleeding, and maintaining normal body temperature until emergency services arrive. Treatment in the hospital may include intravenous fluids, medications, surgery, or other interventions depending on the underlying cause of shock.