When someone is “In Shock” what does that mean and why does this happen?

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When someone is “In Shock” what does that mean and why does this happen?

In: Biology

“Shock,” in a medical context, refers to insufficient blood volume.

Shock can be subdivided into four types, depending on what caused it:

* *Hypovolemic* (low volume) shock is due to blood loss.
* *Cardiogenic* (heart-created) shock, due to a heart attack or similar.
* *Obstructive* shock happens when something poses a mechanical barrier, such as air buildup in the space around the lungs or fluid in the space around the heart.
* *Distributive* shock means the blood can’t get to where it needs to be, usually due to anaphylaxis (hence, anaphylactic **shock**), or certain drug overdoses.

Shock is inadequate perfusion of oxygen to the body’s cells, and is a life threatening condition. It is characterized by:

elevated heart rate

elevated breathing rate

low blood pressure

pale, cool skin

diaphoresis (sweating)

dilated pupils

There are many types and causes of shock, including hypovolemic shock (loss of blood), cardiogenic shock (heart problems), neurogenic shock (brain and spinal cord problems), obstructive shock (cardiopulmonary blood flow problem), aniphylactic shock (allergic reactions), psychogenic shock (psychological cause), septic shock (infections), etc.

All of these causes involve different mechanisms, but all have the same thing in common, which is to impair proper delivery of oxygen throughout the body. Treatment involves maintaining a clear airway, making sure that the patient is breathing or adequately ventilated with supplemental oxygen, maintaining circulation (with CPR or fluid therapy as appropriate), preventing hypothermia / keeping the patient warm, and then treating the underlying condition.

Shock occurs when the organs of your body aren’t able to be perfused adequately (e.g. aren’t getting enough oxygen to them). This causes the organs to not operate properly and as shock progresses the organs become damaged and release harmful substances into the circulation that further worsen the shock state.

Shock can occur due to a problem with the pipes (blood vessels), pump (heart) or fluid (blood volume).

As others have mentioned below, hypovolaemic shock is often due to traumatic blood loss but it can also occur in patients who are severely dehydrated due to vomiting, diarrhoea or severe burns etc. Either way, blood volume isn’t sufficient to circulate oxygen to essential organs.

Cardiogenic shock occurs when the heart has been damaged in some way and isn’t pumping the way it should (e.g. damage to heart muscle or coronary arteries from a heart attack). Blood volume is essentially normal, but the heart isn’t adequately pumping it to where it needs to go.

Obstructive shock occurs when their is a mechanical barrier in the heart or great blood vessels (e.g. pulmonary embolism or cardiac tamponade). Again, blood volume may be essentially normally, but it isn’t being pumped to where it needs to go.

Distributive shock occurs when the blood vessels become ‘large and leaky’. This is common in anaphylaxis (severe allergic reaction) or septic shock (severe infection). You may still essentially have the same blood volume in the body but your ‘pipes’ have increased in size and have become more permeable so again it becomes harder for the body to get the blood circulated to where it needs to go.

Another way you can think of shock – no matter what the cause – is as compensating, decompensating and irreversible.

With compensating shock, the sympathetic nervous system (the ‘fight’ of fight or flight) kicks in by increasing heart rate, breathing rate, constricting blood vessels to keep blood pressure normal, shunting blood to essential organs in an attempt to keep the body going (among other things).

If whatever caused the shock isn’t treated in time, eventually the body can’t compensate anymore so you will start to see a move into decompensating shock – a key symptom of this is when blood pressure starts to drop, the patient may start to become drowsy or confused…

In irreversible shock, the damage has now become too severe to treat – heart rate drops, blood pressure drops, patient loses consciousness and will eventually die.