Shock, the condition where the body and its organs are not getting enough oxygen and nutrients to function normally, can quickly lead to cardiac arrest. On the last post I talked about how we diagnose shock and begin treatment.
The four types of pediatric shock (and also adult shock) are hypovolemic shock, distributive shock, cardiogenic shock, and obstructive shock.
1. In hypovolemic shock, there is not enough fluid in the blood vessels to supply the body with all the oxygen and nutrients it needs. There is low blood volume (hypovolemia).
There are three causes of hypovolemic shock: fluid loss (from diarrhea and vomiting commonly), blood loss (from trauma or bleeding disorders like hemophilia), and capillary leakage (as for example with burns).
2. In distributive shock, the blood vessels become abnormally dilated so that it takes more than the normal amount of blood to fill the blood vessels. And because of the abnormally dilated blood vessels some parts of the body don’t get enough blood flow.
There are five causes of distributive shock.
A.The first is neurogenic shock. Normally the nervous system keeps the blood vessels properly constricted. Brain damage or damage to spinal cord can interfere with nerve function and lead to abnormally dilated blood vessels and to shock.
B. The second is anaphylactic shock caused by reaction to a drug, vaccine, food, or other allergen. There is dilation of vein and of the arteries. The is also capillary leakage of fluid in this form of shock. There is wheezing in the lungs and there can be swelling of the tongue, throat, and face. And so there is not enough blood to fill adequately the dilated and leaking blood vessels.
C. The third cause of distributive shock is certain drugs.
D. Adrenal insufficiency (not enough adrenal hormones) can cause distributive shock.
E. And finally septic shock from severe infection can cause distributive shock where some blood vessels are abnormally dilated and some are inappropriately constricted so that blood flow to different parts of the body does not meet the different needs of the body.
3. The third type of shock (meaning again inadequate blood flow to the body) is cardiogenic shock. In this type the heart unable to pump enough blood to meet the body’s needs.
Causes of cardiogenic shock include heart muscle damage, excessively rapid heart rate, inborn errors of metabolism, and congenital heart disease (structural abnormalities of the heart or blood vessels).
4. The fourth type of shock is obstructive shock. Here the problem is a blockage that interferes with heart’s ability to pump blood. A blood clot in the lungs may prevent adequate blood flow to the heart. A collapsed lung or fluid around the heart can both prevent the heart from being able to pump enough blood.
Pediatric Advanced Life Support Manual, 2011 American Heart Association
Pediatric Fundamental Critical Care Support, 2008 Society of Critical Care Medicine