A severe reduction in blood pressure causing poor blood supply to major organs

  • Age as a risk factor depends on the cause
  • Gender, genetics, and lifestyle are not significant factors

Shock is a potentially life-threatening condition that necessitates immediate medical attention. The medical term shock describes the cold, pale, collapsed state that results from low blood pressure due to serious injury or illness. Left untreated, the reduced blood supply deprives the vital organs and body tissues of oxygen and is eventually fatal.

The condition is unrelated to the psychological and emotional distress that may follow a traumatic experience.

What are the causes?

Shock may develop as a result of any situation in which the heart is unable to pump blood effectively or in which there is too little blood for the heart to pump. The heart is unable to function normally if it is damaged following a heart attack (see Myocardial infarction) or if the heart rhythm is abnormal (see Arrhythmias).

Shock due to insufficient blood circulating around the body may be the result of major blood loss, such as bleeding from the digestive tract or from a serious injury. The volume of blood circulating in the body may also be reduced by fluid loss due to severe burns or profuse diarrhoea.

Some conditions, such as severe allergic reactions (see Anaphylaxis) or a blood infection (see Septicaemia), may cause the blood vessels in the body to widen, resulting in a significant drop in blood pressure and shock.

What are the symptoms?

Shock may not develop until hours after the injury or illness, but as soon as blood pressure falls, the symptoms develop suddenly. Symptoms may include:

  • Confusion or agitation.

  • Cold, clammy skin and sweating.

  • Rapid, shallow breathing.

  • Fast heartbeat.

  • Loss of consciousness.

Symptoms of the underlying cause may also be present, such as prolonged chest pain due to a heart attack.

If shock is not treated immediately, the internal organs may be damaged, leading to various disorders including kidney failure and acute respiratory distress syndrome.

What might be done?

A person in shock requires emergency admission to an intensive therapy unit for treatment and careful monitoring. The priority is to restore the blood and oxygen supply to the body’s major organs regardless of the initial cause of shock. Immediate treatment usually includes oxygen therapy and intravenous fluids, blood or blood products, and drugs to increase blood pressure. Once the cause of shock has been established, specific treatment can be given. For example, antibiotics may be prescribed to treat septicaemia. Surgery may be needed to stop bleeding. For treatment to be successful, the blood supply to the organs must be restored before permanent damage occurs.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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