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Most people think of ‘shock’ as emotional distress or sudden fright in response to a traumatic event. However, in medical terms, shock is when you don’t have enough blood circulating around your body. It is a life-threatening medical emergency.
A drop in blood pressure reduces the flow of oxygen and nutrients to vital organs such as the brain, heart and lungs. If the blood flow is not promptly restored, the person will die from complications including hypoxia (lack of oxygen) or heart attack. Some of the many causes of shock include uncontrolled bleeding, severe burns and spinal injury.
Shock is an adrenalin response
In medical terms, shock is the body’s response to a sudden and dramatic drop in blood pressure. The body responds to this life-threatening situation with an increased release of adrenaline, which aims to maintain blood flow to the vital organs.
Extra adrenaline may also be released into the bloodstream as a result of emotional distress or sudden fright. This is where the confusion in the term ‘shock’ sometimes occurs:
- Medical shock – a severely ill person or someone bleeding profusely. This is a life-threatening emergency that requires prompt medical attention.
- Non-medical shock – we say that a person ‘has had a nasty shock’ if they have experienced a traumatic event such as the unexpected loss of a loved one or a minor car accident.
Symptoms of shock
Depending on the cause, some of the symptoms and signs of shock may include:
- Pale, clammy, sweaty skin
- Shallow, fast breathing
- Breathlessness
- Chest pains
- Heart beat irregularities or palpitations
- Rapid pulse rate
- Dry mouth
- Extreme thirst
- Inability to urinate
- Nausea
- Vomiting
- Incontinence of bowel and bladder
- Light-headedness
- Dilation of pupils
- Confusion and anxiety
- Unconsciousness.
Different types of shock
Some of the different types of medical shock include:
- Hypovolaemic – this means not enough blood volume. Causes include bleeding, which could be internal (such as a ruptured artery or organ) or external (such as a deep wound). Chronic vomiting, diarrhoea, dehydration or severe burns can also reduce blood volume and cause a dangerous drop in blood pressure.
- Cardiogenic – caused when the heart cannot effectively pump blood around the body. Various conditions including heart attack, heart disease (such as cardiomyopathy) or valve disorders may prevent the heart from functioning properly.
- Neurogenic – a spinal injury may damage the nerves that control the diameter of blood vessels, such as arteries. The blood vessels below the spinal injury relax (dilate) and cause a drop in blood pressure.
- Septic – an infection causes the blood vessels to dilate (expand), which drops blood pressure. For example, an E. coli infection or toxic shock syndrome (TSS) may trigger septic shock.
- Anaphylactic – a severe allergic reaction that causes blood vessels to dilate, which results in low blood pressure.
- Obstructive – means that blood flow is stopped. Various causes of obstructive shock include cardiac tamponade (an abnormal build-up of fluid that compresses the heart and stops it from beating properly) or pulmonary embolism (a blood clot in the pulmonary artery, which blocks the flow of blood to the lungs).
- Endocrine – in a critically ill person, a severe hormonal disorder such as hypothyroidism may stop the heart from functioning properly and lead to a life-threatening drop in blood pressure.
‘Non-medical shock’ is an anxiety or fear response. Although the symptoms can mimic those of medical shock, this ‘fright–flight’ response is short lived and symptoms will disappear once the person is comforted or the reason for the fright or fear is removed.
First aid
Medical shock is a life-threatening emergency. Effective first aid and prompt medical care can save a person’s life. First aid suggestions include:
- Do not put yourself in danger of environmental hazards, such as fire.
- Get help, if possible.
- Call triple zero (000) for an ambulance. Do not wait for the person’s condition to improve or worsen.
- Lay the person flat and keep them warm and comfortable. Loosen clothing.
- If the person is unconscious, check breathing and pulse. Begin cardiopulmonary resuscitation (CPR) if needed.
- If the person is breathing but unconscious, gently roll them onto their side with their face angled to the floor. This is so they don’t inhale vomit, saliva or blood. However, if you suspect the person may have a spinal injury, do not move them unless you absolutely must.
- If the person is conscious, try to raise their legs above the level of their torso and head (to improve blood flow to the brain, heart and lungs). However, do not elevate the legs if you suspect a spinal injury or if moving their legs causes pain.
- Treat any obvious signs of external bleeding. For example, firmly press a clean cloth or bandage against a wound to stop blood loss. If blood seeps through and soaks the cloth, do not remove it. Add another cloth over the top of the first one. Keep adding cloths if necessary. Continue maintaining firm pressure against the wound. Raise the bleeding area if possible – for example, an arm or a leg.
- Do not give the person anything to drink, even if they are very thirsty.
- Reassure the person and encourage them to rest or stay still. Stay with them until the ambulance arrives.
- Please note that the above suggestions are not a substitute for first aid training. Refer to the Where to get help section of this fact sheet for organisations that offer first aid courses. Your training may save a life.
Diagnosis
In all cases of medical shock, treatment aims to restore the blood circulation and manage or prevent complications. When the person reaches the emergency department of the nearest hospital, efforts to secure their airway and boost blood circulation are often made before the final diagnosis.
In some cases (such as stab wounds, severe burns or traumatic amputation), the cause of shock is obvious. In other cases, once the patient is out of immediate life-threatening danger, diagnostic tests may be needed to help hospital staff to figure out the cause of the person’s low blood pressure.
Tests may involve:
- Blood tests
- X-ray examinations
- Ultrasound, CT scan or MRI scan (to check for internal bleeding)
- Other tests, depending on the type of shock suspected; for example, diagnosis of cardiogenic shock may involve various tests such as an electrocardiogram (ECG).
Treatment
Specific treatment depends on the type of shock, but could include:
- Hypovolaemic – stop the bleeding and boost blood volume with intravenous fluids. A blood transfusion may be needed in severe cases. Internal or external wounds may require surgical repair.
- Cardiogenic – boost blood volume with intravenous fluids. Drugs may be used to constrict the blood vessels and improve the heart’s ability to pump. Heart surgery may be needed in some cases.
- Neurogenic – intravenous fluids, and drugs including corticosteroids.
- Septic – antibiotics to kill the infection and supportive hospital care as needed: for example, mechanical ventilation to help the person to breathe.
- Anaphylactic – drugs used include adrenaline and corticosteroids.
- Obstructive – treatment to remove the obstruction: for example, surgery or clot-dissolving medication to remove the clot in the pulmonary artery.
- Endocrine – drugs to correct the hormonal imbalance: for example, thyroid medication to treat hypothyroidism.
Supportive treatment for ‘non-medical shock’ generally includes comforting the person or encouraging them to use anxiety management techniques to help manage their symptoms until the reason for their fright or fear is removed.
Outlook
The person’s odds of surviving medical shock depend on various factors including:
- The person’s age and general health
- The type of shock
- The severity of the shock
- How soon medical treatment is given.
Generally speaking, hypovolaemic, neurogenic and anaphylactic shock respond well to treatment. The patient dies in about half of all cardiogenic and septic shock cases.
Where to get help
- Always call triple zero for an ambulance in a medical emergency Tel. 000
- Emergency department of the nearest hospital
- Your doctor
For first aid training, contact:
- St John Ambulance Australia Victoria Tel. 1300 360 455
- Australian Red Cross Tel. 1300 367 428
Things to remember
- Shock is when there is not enough blood circulating in the body. It is a life-threatening medical emergency.
- Some of the many causes of shock include uncontrolled bleeding, severe burns and spinal injury.
- In all cases of shock, medical treatment aims to restore the blood circulation and manage or prevent complications.
- Emotional distress or sudden fright in response to a traumatic event can have similar symptoms to medical shock; however, the symptoms will disappear once the person is comforted or the reason for the fright or fear is removed.
You might also be interested in:
Anxiety disorders.
Bleeding.
Blood pressure.
Breathing to reduce stress.
Cardiopulmonary resuscitation (CPR).
Circulatory system.
First aid kits.
Want to know more?
Go to More information for support groups, related links and references.
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