A condition clinically recognized as a state of inadequate blood flow to tissues. The etiologic classification of shock syndrome comprises four categories: cardiogenic (inability of the heart to pump adequately); neurogenic (interference with control of size of blood vessels caused by a change in balance in nerve impulses); vasogenic (sepsis; due to serious infection); and hematogenic (reduction in circulating blood volume).
Cardiogenic shock is manifested by low blood pressure when there is adequate blood volume. This form of shock is indicated by cold skin, low body temperature, and fast pulse.
Neurogenic shock is seen with clinical fainting. Similarly, neurogenic shock is often observed with serious paralysis of nervous influences. Although the blood pressure may be extremely low, the pulse rate is usually slower than normal and is accompanied by dry, warm, and even flushed skin.
Although any agent capable of producing infection, including viruses, parasites, and fungi, may result in vasogenic (septic) shock, the most frequent etiologic organisms are those that originate in the body, such as in the bowel or urinary tract. The initial infectious process appears to be only a stimulus for a series of body responses that may be fatal, even in the absence of infection at the time of death. Clinically, these individuals usually have high fever, low blood pressure, and eventually cold skin.
Hematogenic shock is the most common form of shock, and it is usually caused by hemorrhage. Most of the signs of clinical shock from low blood volume are characteristic of low blood flow. The skin is usually cold, clammy, and pale, accompanied by a very rapid pulse. See also Cardiovascular system.
