Wednesday, 5 September 2012

What Is Shock?


The most important distinction to make between the different forms of shock, is between psychological (or mental) shock and physiological (or circulatory) shock:
  • Psychological shock can occur after a physically or emotionally traumatic experience but it effects your state of mind (although this can give you symptoms such as palpitations and feeling faint, it doesn’t usually lead to serious physical collapse).
  • Physiological shock is a dramatic reduction in blood flow that, if left untreated, can lead to collapse, coma and even death.

The most common symptoms of shock include:
  • A fast, weak pulse
  • Low blood pressure.
  • Feeling faint, weak or nauseous.
  • Dizziness.
  • Cold, clammy skin.
  • Rapid, shallow breathing.
  • Blue lips.
Causes and risk factors

There are various types of shock with varying causes.

Psychological shock:
This may be caused by:
  • Hearing bad news, such as the death of a loved one.
  • Being involved in a traumatic event, such as an accident.
  • Being the victim of crime, violent or otherwise.

While psychological shock is less likely to kill you than physiological shock, its effects can persist for years and cause immense disruption.

Mild shocks leave you feeling stunned for a while, absorbed in your thoughts and unable to focus on anything else. After a while, though, the brain gets the event in perspective and normal life resumes.

However, especially if the shock is more profound, some people find it harder to return to normal, and may develop post-traumatic stress disorder (PTSD). This tends to affect people in one of three ways:
  • Intrusion - the event is constantly replayed in the mind.
  • Avoidance – the person feels numb, retreats from normal emotions and activities, and may use alcohol and drugs as a form of 'self-medication'.
  • Increased arousal – the person is left angry, and prone to irritable behaviour.
It's essential that PTSD is recognised and treated properly because the earlier it's treated, the greater the chance it can be cured.
Physiological shock:

This type of shock can be caused by:
  • Severe bleeding.
  • Pulmonary embolus (a blood clot in the lungs).
  • Severe vomiting and diarrhoea.
  • Spinal injury.
  • Poisoning.
There are also specific types of physiological shock, with very particular symptoms.
Cardiogenic shock:
Cardiogenic shock occurs when the heart is severely damaged - by a major heart attack, for example - and is no longer able to pump blood around the body properly, causing very low blood pressure. This develops after about eight per cent of heart attacks.

It can be difficult to treat, but drugs may be given to make the heart beat stronger. This may be enough to bring someone through the worst until the heart can mend itself, but cardiogenic shock is still fatal in as many as eight out of ten cases.

New treatments to 'revascularise' or restore blood flow to the heart muscle are improving survival rates.
Septic shock:

This occurs when an overwhelming bacterial infection causes blood pressure to drop. It's fatal in more than 50 per cent of cases.

Although it’s caused by bacterial infection, treating septic shock with antibiotics is far from simple, because the bacteria release massive amounts of toxin when they are killed off, which initially makes the shock worse.

It must always be treated in hospital where the correct drugs and fluid support can be given.

One type of septic shock is toxic shock syndrome - a rare but severe illness caused by certain strains of the bacteriaStaphylococcus aureus.
Anaphylactic shock:

Anaphylactic shock is a severe allergic reaction. Common triggers include bee and wasp stings, nuts, shellfish, eggs, latex and certain medications, including penicillin.

Symptoms include:
  • Burning and swelling of the lips and tongue.
  • Difficulty breathing (like in an asthma attack).
  • Red, itchy or blistered skin, sneezing.
  • Watery eyes.
  • Nausea.
  • Anxiety.
Anaphylaxis requires urgent treatment in hospital. People at risk should always carry an emergency anaphylaxis treatment kit that includes adrenaline.
Treatment and recovery

If you're with someone who goes into shock, prompt treatment can make all the difference:
  • Lay the person flat and raise their legs by at least 25cm to help restore blood pressure (note that in anaphylactic shock, if the person is conscious but having trouble breathing, it's better to sit them up).
  • Stop any bleeding by applying direct pressure over the wound or a tourniquet on extreme limb injuries (it's harmful to stop the blood flow to a limb for more than 10-15 minutes).
  • Administer anaphylaxis treatment if necessary.
  • Loosen tight clothing.
  • Keep the person warm with layers of blankets (not a hot water bottle).
  • Don't give them anything to eat or drink because of the risk of vomiting.
  • Call an ambulance as soon as possible.
By Dr Trisha Macnair

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