The cause of inadequate tissue perfusion (blood delivery to tissues) in<unk>  is a lack of normal responsiveness of blood vessels to vasoconstrictive agents and direct vasodilation. There are four types of<unk> . The most common, septic shock, is caused by an infection, most frequently by bacteria, but viruses, fungi and parasites have been implicated. Infection sites most likely to lead to septic shock are chest, abdomen and genitourinary tract. In septic shock the blood flow in the microvasculature is abnormal with some capillaries underperfused and others with normal to high blood flow. The endothelial cells lining the blood vessels become less responsive to vasocontrictive agents, lose their glycocalyx (normal coating) and negative ionic charge, become leaky and cause extensive over-expression of nitric oxide. The coagulation cascade is also disrupted. Tissue factor that initiates the clotting cascade is produced by activated monocytes and the endothelial cells lining the blood vessels while antithrombin and fibrinolysis are impaired. Disseminated intravascular coagulation (DIC) can result from the thrombin produced in the inflammatory response. The ability of red blood cells to change shape decreases and their tendency to clump together increases, inhibiting their flow through the microvasculature. In anaphylactic shock low blood pressure is related to decreased systemic vascular resistance (SVR) triggered primarily by a massive release of histamine by mast cells activated by antigen-bound immunoglobulin E and also by increased production and release of prostaglandins. Neurogenic shock is caused by the loss of vascular tone normally supported by the sympathetic nervous system due to injury to the central nervous system especially spinal cord injury. Rupture of a hollow organ, with subsequent evacuation of contents in the peritoneal cavity could also determine neurogenic shock, a subtype of<unk> . This happens due to the widespread peritoneal irritation by the ruptured viscus contents, as in peptic ulcer perforation, with consequent strong vagal activation, and generalized, extensive peripheral vasodilation and bradycardia. Thus, in neurogenic shock, there is decreased systemic vascular resistance, CVP is typically decreased, CO decreased or normal, and PAOP decreased.<unk>  associated with adrenal crisis results from inadequate steroid hormones.
Distributive shock
Obstructive shock
Cryptic shock
Hypovolemic shock
Neurogenic shock
Vasodilatory shock
Tumor lysis syndrome
Septic shock