Relative adrenal insufficiency (distributive shock) in critically ill patients where present hormone levels are insufficient to meet the higher demands. Cause
Shock is a common end point of many medical conditions. Shock triggered by a serious allergic reaction is known as anaphylactic shock, shock triggered by severe dehydration or blood loss is known as hypovolemic shock, shock caused by sepsis is known as septic shock, etc. Shock itself is a life-threatening condition as a result of compromised body circulation. It can be divided into four main types based on the underlying cause: hypovolemic, distributive, cardiogenic, and obstructive. A few additional classifications are occasionally used, such as endocrinologic shock. Pathophysiology
There are four stages of shock. Shock is a complex and continuous condition, and there is no sudden transition from one stage to the next. At a cellular level, shock is the process of oxygen demand becoming greater than oxygen supply.One of the key dangers of shock is that it progresses by a positive feedback loop. Poor blood supply leads to cellular damage, which results in an inflammatory response to increase blood flow to the affected area. Normally, this causes the blood supply level to match with tissue demand for nutrients. However, if there is enough increased demand in some areas, it can deprive other areas of sufficient supply, which then start demanding more. This then leads to an ever escalating cascade.
As such, shock is a runaway condition of homeostatic failure, where the usual corrective mechanisms relating to oxygenation of the body no longer function in a stable way. When it occurs, immediate treatment is critical in order to return an individuals metabolism into a stable, self-correcting trajectory. Otherwise the condition can become increasingly difficult to correct, surprisingly fast, and then progress to a fatal outcome. In the particular case of anaphylactic shock, progression to death might take just a few minutes. Initial
During the Initial stage (Stage 1), the state of hypoperfusion causes hypoxia. Due to the lack of oxygen, the cells perform lactic acid fermentation. Since oxygen, the terminal electron acceptor in the electron transport chain, is not abundant, this slows down entry of pyruvate into the Krebs cycle, resulting in its accumulation. The accumulating pyruvate is converted to lactate (lactic acid) by lactate dehydrogenase. The accumulating lactate causes lactic acidosis. Compensatory
The Compensatory stage (Stage 2) is characterised by the body employing physiological mechanisms, including neural, hormonal, and bio-chemical mechanisms, in an attempt to reverse the condition. As a result of the acidosis, the person will begin to hyperventilate in order to rid the body of carbon dioxide (CO2). CO2 indirectly acts to acidify the blood, so the body attempts to return to acid–base homeostasis by removing that acidifying agent. The baroreceptors in the arteries detect the hypotension resulting from large amounts of blood being redirected to distant tissues, and cause the release of epinephrine and norepinephrine.