Circulatory shock

Circulatory shock
Circulatory shock means generalized inadequate blood flow through the body, to the extent that the body tissues are damaged because of too little flow.
Types of shock according to their underline cause:
1-Hypovolemic shock: which include
I-Hemorrhagic shock: Hemorrhage is the most common cause of hypovolemic shock. Hemorrhage decreases the filling pressure of the circulation and, as a consequence, decreases venous return. As a result, the cardiac output falls below normal.

II-Hypovolemic caused by plasma loss: Loss of plasma from the circulatory system, even without loss of red blood cells, can sometimes be severe enough to reduce the total blood volume. Severe plasma loss occurs in the following conditions:
A-Intestinal obstruction is often a cause of severely reduced plasma volume.
B-severe burns cause loss of large amount of plasma from the burned areas.
C-Dehydration: Some of the causes of this type of shock are (1) excessive sweating, (2) fluid loss in severe diarrhea or vomiting, (3) excess loss of fluid by nephrotic kidneys, (4) inadequate intake of fluid and electrolytes, or (5) destruction of the adrenal cortices, with loss of aldosterone secretion and consequent failure of the kidneys to reabsorb sodium, chloride, and water.

III-Traumatic shock: caused by extensive contusion of the body can damage the capillaries sufficiently to allow excessive loss of plasma into the tissues. This results in greatly reduced plasma volume, although there might also be a moderate degree of concomitant neurogenic shock caused by the pain.

2-Cardiogenic shock. This circulatory shock caused by inadequate cardiac pumping. after acute heart attacks and often after prolonged periods of slow progressive cardiac deterioration, the heart becomes incapable of pumping even the minimal amount of blood flow required to keep the body alive. all the body tissues begin to suffer and even to deteriorate. Once a person develops cardiogenic shock, the survival rate is often less than 15 per cent.

3-Neurogenic shock. sudden loss of vasomotor tone throughout the body, resulting especially in massive dilation of the veins lead to Diminish venous return cause decrease cardiac output. (Diminished venous return caused by vascular dilation is called venous pooling of blood).causes of neurogenic shock include: a-deep general anesthesia. b. Spinal anesthesia. C. Brain damage that cause vasomotor depression.
4-Anaphylactic shock is an allergic condition results from an antigen-antibody reaction that takes place immediately after an antigen to which the person is sensitive enters the circulation. This antigen-antibody reaction stimulate mast cell and basophiles to release histamine which cause massive vasodilatation and increased capillary permeability, with rapid loss of fluid and protein into the tissue spaces.
5-Septic shock. This refers to widely disseminated bacterial infection to many areas of the body by the blood and causing extensive damage. Examples of causes of septic shock include Peritonitis caused by rupture of the gastrointestinal system and spread of a skin infection such as streptococcal or staphylococcal infection .A special type of septic shock is endotoxin shock this is caused especially by gram negative bacteria mainly colon bacilli that contain a toxin called endotoxin , as in strangulation of gut, this endotoxin on entering the circulation cause an effect similar to anaphylaxis.