Shock – Definition, causes, stages, and treatment
In medical terms, shock is a state caused by inadequate blood flow to organs and tissues of the body.
It is majorly as a result of a decrease or inadequacy in the amount of blood pumped out of the heart (cardiac output), increase in metabolic rate, a deficiency in the heart which could be from heart valves, ventricles, diseases, etc.
Classification of shock based on its causes
It is also called haemorrhagic shock because it is caused by excessive bleeding. When a person loses so much blood due to an injury or accident, the amount of blood available at that moment for that person is reduced. This leads to a decrease in the pressure at which the ventricles fill with blood, and then a fall in cardiac output.
Sometimes, a blood transfusion might be required to compensate for the blood loss. However, if the cause of haemorrhage is found and arrested immediately, the body can make up for the loss.
Histamine or Anaphylactic shock
When there is an allergic reaction in the body, basophils are released into circulation which leads to the release of histamine or a substance that has the effect of histamine into the blood.
Histamine causes dilation of the veins that return blood to the heart, leading to a decrease in cardiac output. It also causes the pressure in arteries to reduce which will lead to insufficient supply of blood to the body.
This type of shock is caused by a bacterial infection that has spread round the body, causing damages along the line. Septic shock can be caused by:
- Rupture of the gastrointestinal tract (GIT).
If the GIT ruptures, all the contents are scattered into the blood. The GIT contains useful ingredients as well as bacteria, and waste products. The blood circulates these waste products round the body leading to damage.
One of the reasons why it is advisable to treat wounds on time is to prevent infection. Wounds that are kept open and untreated have tendencies of being infected, and this infection can spread throughout the body causing various damages.
- Instrumental Abortion
When a fetus is removed with metallic instruments that have not been sterilized, an infection may ensue.
Inflammation of the peritoneal cavity is called peritonitis; it may be caused by sexually transmitted infections that have spread from the uterus and fallopian tubes.
Blood circulation is controlled by the brain and mediated by neurons; therefore damage to any of these organs will eventually lead to shock. The major causes of neurogenic shock are:
- Brain Damage
Anaesthesia weakens the vasomotor centre which controls blood flow.
- Brain Ischaemia
Ischaemia is a decrease in the supply of oxygen to an organ. When the brain lacks oxygen, it cannot perform optimally.
Stages of shock
Based on severity, and ease of treatment, the shock is classified into three major stages
At this stage, the body is able to make up for the cause of shock without treatment or therapy. The body can adjust by producing more blood, or fighting the infection.
Here, the body’s mechanisms alone are not sufficient to compensate. At this stage, if no treatment is administered, the shock can become irreversible.
At this point, no form of treatment or therapy is enough to keep the person alive, even if the person is active at the moment. This usually happens when brain damage has proceeded for a long time. The brain for instance cannot stay without blood for more than 4 minutes. If there is uncontrolled haemorrhage, and blood supply to the brain is eventually reduced, this stage may ensue.
Signs of shock
- High fever: In septic shock especially, the body temperature will rise above normal
- Dizziness and weakness: When a person loses too much blood, he/she may begin to feel dizzy and weak. This is characteristic of hypovolemic shock.
- Paleness: With a decrease in blood volume, a person may become pale.
- Red cell agglutination: In septic shock, red blood cells begin to agglutinate and form clots due to immune responses.
- Vasodilatation throughout the body
Treatment and therapies for shock
- Blood transfusion
This is the major treatment used in hypovolemic shock
Some drugs that may help reduce vasodilatation, or cure infections may be administered.
Some therapies include
- Oxygen therapy
Ensuring that the person gets enough air into the body could be beneficial.
- Putting the head down
This position helps to increase the amount of blood returned via the veins, hence causes an increase in cardiac output.