Shock is a dangerous physical condition in which the flow of blood throughout the body is drastically reduced, causing weakness, confusion, or loss of consciousness. It can result from many kinds of serious injuries and illnesses. If shock is not treated quickly, a person can suffer permanent organ damage and die.

What Is Shock?

“I studied for days, but I failed the test. I'm in shock,” says one teenager to another.

In everyday speech, the use of the word shock is common and sometimes even enjoyable. People line up to see horror movies because they want to be shocked. They want to feel an emotional jolt from seeing something sudden, surprising, and scary. Their hearts may beat a little faster for a moment, but when the movie ends, they are as healthy as before. We also use the term shock when referring to a psychological shock, such as hearing disturbing news about a loved one or having a traumatic experience. For example, a person who is in a car accident, though not injured, may experience a severe emotional shock.

These kinds of shock have nothing to do with the medical condition called shock. Shock in the medical sense can also be sudden, surprising, and scary, but it is a specific physical condition that is extremely serious.

What Causes Shock?

Shock has three underlying causes. Often, a case of shock involves two or all three of these types of underlying problems. They are as follows:

What Is Septic Shock?

Septic shock occurs when a person becomes infected with bacteria that get into the bloodstream and produce a dangerous level of toxins (poisons). Even when treated, it is sometimes fatal.

It is most common among hospitalized people who have recently had surgery, or who have had drainage tubes, breathing tubes, or other devices inserted into their body. Such devices increase the chances that bacteria will get into the bloodstream.

Other people at risk of septic shock are those with weakened immune systems, including those who have diabetes, cirrhosis * , leukemia * , or AIDS * . Newborns and pregnant women are also at risk.

Toxic shock syndrome is a form of septic shock that experts originally linked to use of certain tampons.

Electrical Shock

An electric current that passes through the body is called a shock. Although such a shock is often dangerous (electrical accidents kill about 1,000 people per year in the United States), electrical shock is different from medical shock.

Medical shock is a reduction in blood flow. Electrical shock, by contrast, primarily causes internal burns and disruption of heart rhythms. In some cases, an electrical shock can cause medical shock. This situation occurs if the burns lead to rapid loss of fluid and the heart problems prevent adequate pumping of blood.

What Is Anaphylactic Shock?

Anaphylactic (an-a-fi-LAK-tik) shock is a severe allergic reaction. Depending on the individual, the trigger may be a certain medication, a blood transfusion * , a bee sting, or particular foods, such as peanuts. During anaphylactic shock, fluid leaks out from the blood vessels and the blood vessels dilate. This type of shock is sometimes fatal.

What Are the Symptoms of Shock?

Whatever its cause, people in shock have rapid and shallow breathing, cold and clammy skin, a weak but rapid pulse, low blood pressure, and weakness all over the body. They are dizzy and confused and may lose consciousness.

How Is Shock Treated?

People in shock require immediate transport by ambulance to a hospital. Until the ambulance arrives, a friend, family member, or other onlooker should take on the role of caregiver and have the person lie down on the back with the feet raised about a foot higher than the head. This position helps get the blood flowing to the brain and heart. The caregiver should also cover the person with a coat or blankets to keep the individual warm. Medical workers will try to raise the blood pressure by giving fluids intravenously (through a needle into a vein). If the shock was caused by blood loss, they may also start a blood transfusion. If the blood pressure still remains dangerously low, they may use drugs known as pressors to raise the blood pressure. For anaphylactic shock, medical professionals give the drug epinephrine (ep-i-NEF-rin), also called adrenaline * , to constrict (narrow) the blood vessels. For septic shock, doctors may give the drug drotrecogin alpha, and in some cases they may prescribe corticosteroids * but only at low dosage. Several studies of high-dosage corticosteroid therapy have shown it is not beneficial and may even be damaging. Another common treatment for shock is oxygen. Medical professionals routinely administer oxygen, and in some cases they may put the patient on a ventilator (a breathing machine) to increase the amount of oxygen getting to the cells. If septic shock is suspected, they may also give intravenous antibiotics.

Once the person is out of immediate danger, doctors can try to treat the underlying cause of the shock.

How Can Shock Be Prevented?

Individuals can reduce their chances of experiencing shock by following safety rules to prevent fires and serious accidents, including car crashes. To avert bacterial infections that can cause septic shock, hospitals have rules about sterilizing equipment and washing hands. To prevent anaphylactic shock, people with allergies must take care to avoid the foods or other substances that trigger them, and carry an epinephrine autoinjector (EpiPen) to use in case of accidental exposure.

See also Allergies • Aneurysm • Bites and Stings • Burns • Heart Disease: Overview • Post-Traumatic Stress Disorder (PTSD) • Sepsis • Toxic Shock Syndrome • Trauma


Books and Articles

Le Baudour, Christopher, and J. David Bergeron. Emergency Medical Responder: First on the Scene, 10th ed. Boston, MA: Pearson, 2016.


Better Health Channel. “Shock.” (accessed July 9, 2016).

Chicago Electrical Trauma Rehabilitation Institute (CETRI). “Electrical Injury.” (accessed July 9, 2016).

MedlinePlus “Shock.” U.S. National Library of Medicine. (accessed July 9, 2016).

NHS Choices. “Septic Shock.” (accessed July 9, 2016).

University of Maryland Medical Center. “Shock.” (accessed July 9, 2016).


American Academy of Allergy, Asthma, and Immunology. 555 East Wells St., Suite 1100, Milwaukee, WI 53202-3823. Telephone: 414-272-6071. Website: (accessed July 9, 2016).

* aortic aneurysm (ay-OR-tik ANyoo-rizm) is a weak spot in the aorta, the body's largest blood vessel. The weak spot can rupture or break, causing massive internal bleeding.

* blood clot is a thickening of the blood into a jellylike substance that helps stop bleeding. Clotting of the blood within a blood vessel can lead to blockage of blood flow.

* cirrhosis (sir-O-sis) is a condition that affects the liver, involving long-term inflammation and scarring, which can lead to problems with liver function.

* leukemia (loo-KEE-me-uh) is a form of cancer characterized by the body's uncontrolled production of abnormal white blood cells.

* AIDS, or acquired immunodeficiency (ih-myoo-no-dih-FIH-shensee) syndrome) an infection that severely weakens the immune system; it is caused by the human immunodeficiency virus (HIV).

* blood transfusion is the process of giving blood (or certain cells or chemicals found in the blood) to a person who needs it due to illness or blood loss.

* adrenaline (a-DREN-a-lin), also called epinephrine (ep-e-NEF-rin), is a hormone, or chemical messenger, that is released in response to fear, anger, panic, and other emotions. It readies the body to respond to threat by increasing heart rate, breathing rate, and blood flow to the arms and legs.

* corticosteroids (kor-tih-ko-STIRoyds) are chemical substances made by the adrenal glands that have several functions in the body, including maintaining blood pressure during stress and controlling inflammation. They can also be given to people as medication to treat certain illnesses.

  This information is not a tool for self-diagnosis or a substitute for professional care.