Shock occurs when inadequate blood flow threatens the function of multiple organs. Shock is a potentially life-threatening condition. The sooner it is treated, the better the outcome. If you suspect someone is in shock, call for medical help right away.

Causes    TOP

Some causes of shock include:

  • Heart failure
  • Heart attack
  • Spinal cord injury
  • Infection of the blood— sepsis
  • Other severe infection
  • Allergic reaction
  • Poisoning
  • Loss of blood volume (hypovolemia)—this can be from severe bleeding or severe dehydration
  • Heatstroke
  • Trauma
  • Severe hypoglycemia
  • Stroke

Risk Factors    TOP

Factors that may increase your chance of shock include:

  • Pre-existing heart or blood vessel disease
  • Impaired immunity
  • Severe allergies
  • Severe trauma
  • Diabetes

Symptoms    TOP

The symptoms of shock depend on the cause.

Symptoms may include:

  • Weakness
  • Altered mental status
  • Cool and clammy skin
  • Pale or mottled skin color
  • Low blood pressure
  • Decreased urination
  • Weak and rapid pulse
  • Slow and shallow or rapid and deep breathing
  • Lackluster (dull) eyes
  • Dilated pupils
  • High or low body temperature

Symptom of Shock

Dilated and Constricted pupil
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Diagnosis    TOP

A physical exam will be done.

Tests may include the following:

  • Breathing assessment
  • Blood pressure measurement
  • Heart rate monitoring
  • Other testing depending on the cause of shock
    • Blood tests and cultures
    • Electrocardiogram
    • Imaging studies

Treatment    TOP

Treatment options include the following:

Breathing Resuscitation

If you are having trouble breathing, your doctor will clear your airway. Oxygen and breathing assistance may be provided if you need it.

Optimizing Blood Pressure and Heart Rate

You will receive an IV for fluids and/or blood transfusions. These will stabilize your blood pressure and heart rate.

Insertion of IV for Transfusion or Medications

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Medications    TOP

You may be given vasopressors. These medications constrict your blood vessels to increase blood pressure. Drugs may also be used to increase your heart contractions. Other medications may be used depending on the underlying cause.

Prevention    TOP

To help reduce your chance of shock:

  • Prevent or control heart or vascular disease.
  • Avoid activities that put you at risk of falls or other injuries.
  • Carry an epinephrine pen with you if you have a severe allergy.
  • Manage conditions, such as diabetes, as advised by your doctor.


American College of Emergency Physicians
National Heart, Lung, and Blood Institute


Canadian Association of Emergency Physicians
Canadian Red Cross


Hypovolemic shock. EBSCO DynaMed website. Available at:
...(Click grey area to select URL)
Updated December 3, 2013. Accessed January 7, 2014.
The signs of hypovolemic shock. Health Guidance website. Available at:
...(Click grey area to select URL)
Accessed January 7, 2014.
Explore cardiogenic shock. National Heart, Lung, and Blood Institute website. Available at:
...(Click grey area to select URL)
Accessed January 7, 2013.
Last reviewed December 2014 by Michael Woods, MD
Last Updated: 12/20/2014

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